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• Critical moment (or Interval)
  41 bytes (5 words) - 20:18, 30 January 2014
• Two- or three-dimensional interpretation
  #REDIRECT [[Seismic data: two- or three-dimensional interpretation]]
  68 bytes (7 words) - 16:05, 21 November 2014
• Seismic data: two- or three-dimensional interpretation
  ...lts, channels, and other features of interest. There will always be faults or channels oriented at angles between 0° and 45° relative to the orientatio
  8 KB (1,280 words) - 17:33, 25 January 2022

Page text matches

• Dry hole
  ...[economics]] and technologies change, yesterday's dry hole may be revived (or a twin to it may be drilled) to yield today's successful well.
  322 bytes (52 words) - 13:44, 18 March 2019
• Interval transit time
  ...ic log, usually in units of μs/ft or μs/m. It is also seen as ''delta t'' or ''Δt''.
  205 bytes (40 words) - 20:03, 14 April 2014
• Biodegradation
  ...r methanogenic) biodegradation during migration or while in the reservoir, or at surface seeps, typically at temeraptures approximately less than 80°
  791 bytes (108 words) - 19:58, 25 June 2015
• AAPG Wiki:Privacy policy
  When making an edit or creating a new page on '''{{SITENAME}}''', contributors agree to these uses ...loads, for the purposes of tracking usage volume, diagnosing access issues or problems with the wiki server, and to administer the website.
  2 KB (333 words) - 15:37, 9 October 2013
• Bioturbation
  ...y and permeability. For instance, burrows filled with sand grains in a mud or clay unit could be conduits for fluid flow if connected. Bioturbation can o
  907 bytes (132 words) - 21:42, 18 September 2014
• Accumulation
  ...ot contain oil or gas. Accumulations, or pools, are traps that contain oil or gas.<ref name=Vincelette>Vincelette, R. R., E. A. Beaumont, N. H. Foster, 2 ...s smaller than the carrier bed. The seal pore throat breakthrough pressure or the distance to the spill point of the trap, whichever is less, determines
  1 KB (206 words) - 17:37, 27 January 2015
• Strike
  ...lly written as N25E, to distinguish it from dip, which is written 4S, 4SE, or 4 65SE.
  585 bytes (88 words) - 16:06, 11 September 2014
• AAPG Wiki:Governance documents
  ;Privacy policy: What one may or may not do with a user's data or behaviour. ;Copyrights: or '''Licensing''' — how people can use the content.
  3 KB (373 words) - 16:41, 31 July 2013
• Contour
  ...hores), differences between two seismic events or reflections (isochrons), or any variables that can be mapped.
  540 bytes (69 words) - 20:24, 27 March 2015
• Two- or three-dimensional interpretation
  #REDIRECT [[Seismic data: two- or three-dimensional interpretation]]
  68 bytes (7 words) - 16:05, 21 November 2014
• Asphaltenes
  ...remaining oil consists of saturates, aromatics, and nitrogen, sulfur, and/or oxygen (NSO) compounds.<ref name=Petersetal_2012>Peters, Kenneth E., David
  886 bytes (126 words) - 16:34, 25 June 2015
• AAPG Wiki:Wiki manager
  ...h static web content, but is more akin to the AAPG's nascent blog channel, or its membership engagement functions. ...ted, content-oriented, and technical. They don't have to be a geoscientist or even a petroleum professional, but it would help.
  2 KB (294 words) - 16:44, 22 July 2013
• Logging while drilling
  ...tion (look-ahead seismic profiles). Data can be transmitted to the surface or stored for later retrieval.
  2 KB (206 words) - 21:17, 3 December 2015
• Free water level
  ...m. It produces water only. Zero [[buoyancy pressure]] exists at this level or below.
  525 bytes (76 words) - 14:40, 8 September 2014
• Liptinite
  ...ured (e.g., [[resinite]], [[sporinite]], or [[cutinite]]) and unstructured or amorphous liptinites, sometimes called [[amorphinite]], can occur.<ref name
  788 bytes (102 words) - 19:51, 25 June 2015
• Trap systems: structural, stratigraphic, and fluidic
  The proposed classification scheme divides [[trap]]s into three main groups or systems, based on the controlling geologic element that created the trap: ...ure|syndepositional]] [[deformation]] or displacement of [[reservoir]] and/or [[seal]]ing units
  3 KB (405 words) - 17:44, 12 April 2022
• AAPG Wiki:General disclaimer
  ...of the Content and shall not have any liability whatsoever for any direct or consequential damages resulting from the use of any information obtained th ...this Web site or cited, used or discussed in AAPG copyrighted publications or in presentations at events associated with AAPG.
  4 KB (654 words) - 18:31, 2 August 2013
• Sidetrack
  ...entionally or may occur accidentally. A [[multilateral well|multilateral]] or [[multilevel well]] will have multiple intentional sidetracks drilled to pr
  1 KB (191 words) - 19:41, 3 March 2016
• Hydrocarbon column
  This term refers to a vertical measure of the reservoir or trap containing hydrocarbons.
  165 bytes (22 words) - 19:51, 14 April 2014
• Fault trap regime
  ...ows definitions and examples for the classes and subclasses of these traps or trapping elements. ...ne or more sides by normal faults. Rotation traps hydrocarbons along edges or in corners.
  5 KB (740 words) - 16:04, 13 April 2022
• Sand peel
  ...pture of details in sedimentary features for analysis away from the field, or for use in teaching.
  2 KB (239 words) - 19:40, 9 September 2014
• Deasphalting
  ...deasphalting is achieved by adding light hydrocarbons, such as [[pentane]] or [[hexane]], to the oil. A similar process can occur in nature when [[methan
  864 bytes (120 words) - 19:55, 25 June 2015
• AAPG Wiki:Users
  ==User types or roles== | '''Root''' || 3 || Login || No || All || The person or people who can log into the server and edit LocalSettings.php
  2 KB (294 words) - 16:01, 6 August 2013
• Pore systems
  ...ned [[sandston]]e might be classified as having intergranular mesoporosity or a [[limestone]] as having vuggy macroporosity. |Mega/macro || Clean, coarse sandstone or [[carbonate]] [[grainstone]] ||
  3 KB (442 words) - 13:52, 4 April 2022
• Types of diagenetic traps
  [[Diagenesis|Diagenetic]] traps occur in two basic categories: early or near-surface traps and late-burial traps. Early or near-surface diagenetic traps are created by the following:
  2 KB (294 words) - 21:01, 4 February 2022
• Hiatus
  A break or discontinuity in a process. An [[unconformity]] is the physical representa
  217 bytes (28 words) - 20:48, 25 August 2014
• Fluid-composition trap regime
  Fluid-composition traps are controlled by the physical or chemical properties of the trapped fluids themselves. The [[Wikipedia:Solub ...[[asphalt]], [[tar]]) or solid hydrocarbons ([[albertite]], [[gilsonite]], or [[grahamite]]). || ''Tar Seals'' || ''Bacterial degradation;'' Updip tar se
  3 KB (402 words) - 16:31, 13 April 2022
• Syncline
  ...ts such as tilting or faulting, among others, a fold should have its crown or crest as the [[anticline]] and the trough of its structures as the syncline ...olded. This is the best term used to describe it rather than “downward arc or trough of a fold” this is because due to events when strata has been over
  3 KB (505 words) - 15:58, 21 March 2019
• Fold
  ...[[uplift]]. Folds are expressed in [[seismic reflection profile]]s as one or more regions of dipping reflections ([[dip]] domains) that correspond to in ...hether or not the thickness of stratigraphic layers changes in dip domains or across axial surfaces.
  3 KB (495 words) - 15:09, 18 January 2016
• Petroleum system identification
  ...leum system. An oil or gas seep, a show of oil or gas in a well, or an oil or gas [[accumulation]] demonstrates the presence of a petroleum system.
  2 KB (298 words) - 18:35, 25 January 2022
• How different structural philosophies govern techniques
  ...al geology, and various university departments and E&P companies favor one or another in their courses and approaches to problem-solving. The major appro * Detailed geometric and/or kinematic studies
  3 KB (422 words) - 20:17, 3 February 2022
• Paleogeography and prospect identification
  ...l analysis of clastic depositional systems#Shoreline deposits|shorelines]] or [[reef]]s. Mapping thickness of reservoir-quality rocks is also useful for ...ial for containing reservoir rocks, i.e., [[Third-order sequences|lowstand or highstand]], using biostratigraphic markers and regional correlation surfac
  4 KB (491 words) - 14:27, 21 March 2022
• Paleontologic data
  ...tratigraphic correlation and age determination|biostratigraphic analysis]] or in a geographic array for [[Paleoenvironmental analysis|evaluating paleoenv * Records of species present or absent
  2 KB (268 words) - 15:18, 31 January 2022
• Paleocurrent
  [[file:1024px-WaveRipple.JPG|thumb|300px|Wave ripple or symmetric ripple, from Permian rocks in Nomgon, Mongolia. Photo by [https:/
  372 bytes (51 words) - 22:00, 17 March 2015
• Isochron
  Time interval (or isotime or isochron) maps are commonly used for interpreting changes in thickness betw
  1 KB (135 words) - 14:13, 24 November 2015
• Bend
  ...]], in which the well path is designed to change orientation from vertical or high-angle to horizontal.
  1 KB (173 words) - 15:33, 16 March 2016
• Build rate
  ...ough the bend (curve) from vertical or high-angle to the desired low-angle or horizontal attitude.
  1 KB (174 words) - 19:33, 3 March 2016
• Molecular parameter data for oil–oil and oil–source rock correlations
  ...e or on the relative or absolute abundance of specific molecules in an oil or a [[source rock]] extract. ...can be obtained. In addition to correlating an oil directly to another oil or to a source rock extract, certain molecular parameters can be used to estim
  2 KB (294 words) - 21:02, 15 February 2022
• Basement
  Basement is rock below a sedimentary cover, often [[igneous]] or metamorphic. It is generally not of interest in exploration for oil and ga
  264 bytes (40 words) - 15:52, 10 March 2016
• Limitations of quantitative fault seal analysis
  ...ale]] sequences. It is not applicable to massive [[carbonate]], [[chert]], or sandstone reservoirs. It has yet to be tested in interbedded shale–carbon ...th which a seal can be risked is thus much greater in a production setting or mature basin than it is in a frontier setting.
  3 KB (398 words) - 17:35, 29 March 2022
• Extended-reach wells
  ...refers to wells restricted to a platform or pad (because of environmental or economic contraints) that are attempting to access reserves at a significan
  1 KB (186 words) - 19:42, 3 March 2016
• AAPG Wiki:Ease of use
  ...erences, journals or ability to cut and paste an equation macro into excel or other applications *'''Printing''' - make it easy to print entire articles or selected subsets
  2 KB (266 words) - 15:49, 6 August 2013
• Trap classification levels
  ...eologic element || Dominant control of the trap—structural, stratigraphic, or fluidic. ...sses? If the trap is fluidic, was closure formed by pressure, temperature, or chemical processes?
  5 KB (665 words) - 18:47, 12 April 2022
• Petroleum system naming
  A unique designation or name is important to identify a person, place, item, or idea. As geologists, we name rock units, fossils, uplifts, and basins. The | A positive [[Oil-oil and oil-source rock correlation|oil-source rock]] or gas-source rock correlation
  3 KB (367 words) - 18:35, 25 January 2022
• Fracture traps
  ...he structural system because fractures are a result of [[deformation]] and/or displacement and therefore are structural in nature. ...ractured rock or by change from open, permeable fractures to cement-filled or narrow-aperture, low-permeability fractures.
  3 KB (461 words) - 16:04, 13 April 2022
• Quantitative paleoenvironmental analysis
  ...into clusters. The results of the cluster analysis show faunal groupings, or ''biofacies'', which are often characteristic of specific environments. [[: ...r geologic data to determine or evaluate specific paleoenvironmental zones or settings.
  4 KB (493 words) - 20:00, 31 January 2022
• Buoyancy pressure
  Buoyancy is the tendency for a body (or a drop of immiscible fluid) to float or rise when submerged in a fluid of greater [[density]]. Where two immiscible ...re#Capillary pressure concepts|capillary effect]]s—such as a bottle, lake, or cave—the different fluids exhibit a sharp, flat interface.
  4 KB (596 words) - 18:37, 17 February 2022
• Selecting a surficial geochemistry survey method
  ...er area, to high-grade previously defined exploration leads and prospects, or to determine the type of petroleum (i.e., oil vs. gas) likely to be encount ...cal methods have previously been used successfully in the area of interest or in a geologic analog area?
  6 KB (809 words) - 17:05, 25 January 2022
• Fossil assemblage
  Fossil assemblages, or faunal assemblages, are simply groups of fossils found together in strata.
  484 bytes (58 words) - 20:11, 12 March 2015
• Surficial geochemical exploration principles
  ...xploration for petroleum is the search for chemically identifiable surface or near-surface occurrences of hydrocarbons and their alteration products, whi * Hydrocarbon seepage can be active or passive and is visible (macroseepage) or only detectable analytically (microseepage).
  5 KB (687 words) - 19:23, 24 January 2022
• Surficial geochemistry: limitations and uncertainties
  ...very real and can significantly affect the [[economics]] of an exploration or development program, the user must be aware of limitations associated with * False seep anomalies can be caused by reworked [[hydrocarbon]]s and/or reworked [[source rock]]s.
  3 KB (418 words) - 21:19, 24 January 2022
• Tertiary migration
  ...rocarbon migration|Migration]] to the surface, either from a [[reservoir]] or [[source rock]]. Also called dismigration.
  440 bytes (58 words) - 21:47, 25 June 2015
• Trap
  * '''Trap seal'''—an impediment or barrier that interferes with hydrocarbon [[migration]] from the reservoir. ...en reservoir and seal, or (2) boundaries between fluids, such as oil–water or gas–water contacts. Temperature can also control a trap boundary as displ
  4 KB (614 words) - 17:02, 12 April 2022
• Type IV kerogen
  ...ee common source rock evaluation errors made by geologists during prospect or play appraisals]: AAPG Bulletin, vol. 93, issue 3, pp. 341-356.</ref>]] ...in thermally immature rocks; dominated by organic matter that was recycled or extensively oxidized during deposition. Sometimes the type IV pathway is no
  1 KB (185 words) - 21:11, 6 July 2015
• Fold trap regime
  ...p. 219-235.</ref> || rowspan = 2 | ''Local anticline'' || ''Fault bounded or cross faulted'' || ''Relief, symmetry, internal faulting, internal geometry ...rom the horizontal in one direction only and are not a part of a anticline or syncline.<ref name=ch02r11>Rittenhouse, G., 1972, [http://archives.datapage
  6 KB (742 words) - 14:42, 13 April 2022
• Structural maps and cross sections
  ...ect, regardless of local structural style, level of structural complexity, or exploration maturity: ...tratigraphic thickness variation or has behaved in a [[Ductility|ductile]] or compactive manner during [[deformation]].
  4 KB (504 words) - 14:17, 2 February 2022
• How to use the trap classification scheme
  ...hic, structural, or fluidic traps. But many traps are a combination of two or three geologic elements. In these traps, basic trapping elements occur in c
  1 KB (191 words) - 18:46, 12 April 2022
• Pore system fundamentals
  ...-D pore system geometries found in intergranular, intercrystalline, vuggy, or fractured rocks. ...-D pore system geometries found in intergranular, intercrystalline, vuggy, or fractured rocks. Copyright: Coalson et al.;<ref>Coalson, E. B., S. M. Gools
  3 KB (388 words) - 13:52, 4 April 2022
• Basin-fill and trap analysis
  ...h. Basin-fill analysis is looking for [[Stratigraphic trap|stratigraphic]] or [[combination trap]]s by combining [[paleogeography]] with the results of t
  1 KB (189 words) - 18:53, 4 February 2022
• Fracture trap regime
  ...otally mineralized by postfracture cements, typically calcite, [[gypsum]], or silica. | ''Nonmineralized fracture''; Contains no postfracture cements or minerals.
  7 KB (895 words) - 16:04, 13 April 2022
• Migration pathway map construction
  ...or [[Cross-leaking faults|cross-leak]] and [[Dip-sealing faults|dip-seal]] or [[Dip-leaking faults|dip-leak]]. ...s real JLLPs, areas of cross-seal or cross-leak, and areas of [[dip]] seal or dip leak
  3 KB (405 words) - 18:19, 29 March 2022
• Archie equation
  * Non-Archie pore geometries (i.e., not intergranular or intercrystalline) (See [[Pore systems]].) ...stments. The table below lists the five variables and methods for deriving or estimating them.
  5 KB (703 words) - 13:52, 5 April 2022
• Fracking
  ...fluid is lifted to the surface of the back is often called produced water or flowback water. In practice, the withdrawal of fracking fluid to the surfac ...t least 2 times until water is considered feasible to naturally evaporated or removed kesaluran common disposal.
  3 KB (484 words) - 21:18, 27 March 2019
• Structural styles: data and techniques for evaluation
  ...vidual structures generally have good [[strike]] continuity and poor depth or [[dip]] continuity. Hence, in any newly discovered thrust belt, these same If and when one or more structural styles are ascribed to an area, certain of the structural t
  3 KB (420 words) - 20:13, 3 February 2022
• Erosional trap regime
  ...boundaries occur along contacts between erosional surfaces and underlying or overlying [[reservoir]s. ...and bottom seals beneath the unconformity. || Regional subcrop; Uniformly or gently dipping reservoir bed beneath an unconformity. Top seal is provided
  5 KB (588 words) - 16:13, 13 April 2022
• Kerogen type and quality: visual assessment
  ...g transmitted light through a microscope to determine its form (structured or amorphous) and origin. Structured kerogens include woody, herbaceous, [[The ...kerogen in a sample derived from cuttings composites or core (conventional or sidewall). For example, a visual estimate of kerogen type might be stated a
  2 KB (300 words) - 18:17, 9 February 2022
• Interpreting hydrocarbon shows
  ...indications of hydrocarbons—seen in [[drilling fluid]]s, cuttings, cores, or formation tests—may be of several types:<ref name=ch09r55>Schowalter, T. | Continuous phase || Trapped oil or gas || A slug or filament of oil or gas with a continuous connection through the pore network of a rock
  8 KB (1,130 words) - 17:09, 5 April 2022
• Pressure trap regime
  ...[[pressure gradient]]s to [[Overpressure causes|overpressure]]s can create or destroy [[Pressure compartment seals|pressure seals]] and create isolated [ | Tilted oil–water contacts; Boundary defined by tilted oil–water or gas–water contact. || colspan = 2 | Hydrodynamic traps; Tilted hydrocarbo
  3 KB (331 words) - 16:30, 13 April 2022
• Natural-gas liquids
  ...at natural-gas processing plants are called [[natural-gas plant liquids]] or [[liquefied petroleum gasses]] and consist primarily of ethane, propate, bu ...o obtain. The total amounts of NGL, or of the lease condensate production, or both, are commonly reported as part of the [[crude oil]] production, and wh
  4 KB (549 words) - 16:31, 25 June 2015
• Reservoir system
  ...uilibrium with a [[free water level]] (zero buoyancy pressure). It has one or more containers and is located below a seal. ...ble rock 100% saturated with water. It has one or more containers that may or may not be shared with a reservoir.
  4 KB (579 words) - 14:34, 1 April 2022
• Diagenetic impact on traps
  ...acies or paleostructure. However, if [[diagenesis]] does not follow facies or paleostructure, then the exploration and exploitation risk increases becaus
  2 KB (297 words) - 21:06, 3 February 2022
• Preparing to go to the field
  ...ning about the formations in the study area—even driving the seismic lines or flying over the area. ...in the necessary permissions from owners and/or authorities to access land or airspace. It's a good idea to get permissions in writing and carry them wit
  5 KB (730 words) - 22:36, 1 February 2022
• Seal failure prediction
  ...lace through micropermeable lithologies ([[Micropermeable seal leakage]]), or gas is diffused ([[Diffusive seal leakage]]). The most likely mechanism is ...ure|fracturing]] during [[deformation]] or by cumulative micropermeability or [[Diffusive seal leakage|diffusive seal loss]].
  4 KB (571 words) - 18:06, 1 February 2022
• Agglutinated microfossils
  ...e of stratigraphically significant agglutinated microfossil: agglutinated, or arenaceous, foraminifera. ...orms may include silt or sand grains, [[glauconite]], [[sponge spicule]]s, or even other foraminiferal tests. Some species are highly selective in the ma
  4 KB (468 words) - 15:16, 31 January 2022
• Diagenetic trap regime
  ...to postdepositional diagenetic processes, which can create new reservoirs or new seals. ...d_flow_characterization#Dissolution_and_associated_processes|dissolution]] or [[Carbonate_reservoir_models:_facies,_diagenesis,_and_flow_characterization
  5 KB (645 words) - 16:14, 13 April 2022
• Functions of a petroleum landman
  ...the case of an independent landman, the functions vary depending upon his or her area of specialization. Generally, these functions can be divided into ...ades, well trades, joint venture agreements, creation of partnerships, and/or acquisition of entities.
  5 KB (759 words) - 19:25, 19 January 2022
• EMD Tight Oil & Gas Committee Annual Reports
  ...l session focused on the committee’s area of interest at an annual, region or section meeting of the AAPG; * (c) technical paper presented at an oral or poster session of an AAPG meeting, with slide deck published on Search and
  3 KB (417 words) - 20:29, 20 September 2022
• Gravity data processing
  ...ues over deep ocean basins because of variations in the crustal thickness, or ''[http://www.hko.gov.hk/education/edu06nature/ele_isostasy_e.htm isostasy] * Upward or downward continuation—a process that attenuates or deattenuates data to simulate what might be observed at different vertical
  4 KB (519 words) - 14:16, 31 January 2022
• Predicting hydrocarbon recovery
  ...l ([http://www.enggcyclopedia.com/2012/03/gas-oil-ratio-gor/ gas-oil ratio or GOR]). For example, if a well has a GOR of 1,000, then B_oi = 1. ==Estimating recoverable volume of oil or gas==
  5 KB (691 words) - 17:10, 5 April 2022
• Postprimary migration and compositional changes
  ...tion path; (2) mixing [[migration]] streams from two or more source rocks; or (3) precipitation of [[asphaltenes]] and other high-molecular-weight compou ...mum probability of interactions. However, if the petroleum moved as a slug or filament, contact with elements that could alter its composition would be m
  5 KB (694 words) - 15:17, 14 February 2022
• Phases of a seismic project
  ...ruined by sloppy acquisition methods. Common culprits are poor positioning or cabling information (i.e., which receivers are live for which shots). For m ...n acquisition footprint. One should avoid footprints because they can mask or confuse geologic patterns in the data.
  3 KB (455 words) - 22:00, 25 January 2022
• Special field techniques
  ...ds or lithologic horizons on well logs, separated by distance, as the same or correlative interfaces in the earth), particularly when significant distanc ...ing, thick vegetation, and/or thin [[alluvial]] cover. A seismic shot hole or water well drilling rig can be strategically positioned for collecting such
  3 KB (412 words) - 22:40, 1 February 2022
• Maturation
  ...ecting its [[Thermal history|thermal]] and [[burial history]]. This change or maturation is measured and can be combined with quality and richness data t ...ed from most maturation indices is dependent on the type of organic matter or material being analyzed.
  3 KB (421 words) - 18:26, 9 February 2022
• Reservoir drive mechanisms
  * Rock or compaction drive ...reservoir and has a much larger volume than the reservoir (about 10 times) or is in communication with surface recharge. A strong water drive is more eff
  7 KB (1,052 words) - 18:45, 1 April 2022
• Selling a structural play
  ...to be accepted, we must construct a coherent explanation of the mechanics or tectonics responsible for creating the play. Such explanations can be any o * Appropriate physical and/or mechanical models that clarify the structure's development
  5 KB (738 words) - 15:58, 2 February 2022
• Drilling problems
  ...Typically, a dogleg is caused by a change in the [[dip]] of the formation or by a change in the weight applied to the bit. Severe doglegs can result in ...ally form as a result of dog legs. A ''key seat'' is formed when a channel or groove is cut in the side of the hole, parallel to the axis of the hole. Th
  5 KB (732 words) - 21:18, 19 January 2022
• Economics: fundamental equations for oil and gas property evaluation
  ==Profit or loss equation== ...of any business venture can be expressed as the difference (either profit or loss) between revenue and costs. In other words,
  6 KB (842 words) - 19:26, 19 January 2022
• Paleogeography
  ...]. Once an [http://en.wiktionary.org/wiki/isochronous isochronous] surface or coeval interval is identified, paleogeography can be reconstructed by integ
  2 KB (242 words) - 15:48, 1 March 2022
• Scientific method
  The logic sequence, or ''scientific method'', has been the basis of scientific work since the time # Test predictions by observing occurrences or nonoccurrences of the predicted phenomena.
  3 KB (380 words) - 14:31, 18 February 2022
• Laurentia
  ...million years or so. Continents can grow when two plates collide, welding, or accreting, the two pieces together. Continents also grow when [[oceanic cru
  2 KB (248 words) - 22:12, 3 December 2015
• Predicting preservation and destruction of accumulations
  ...Other accumulations, however, may be destroyed. Several processes deplete or destroy hydrocarbon accumulations. In many prospects it is not enough just ...lossary.oilfield.slb.com/en/Terms/n/natural_gas.aspx gas] has been diluted or altered so that [[accumulation]]s are no longer economic.
  5 KB (782 words) - 22:36, 31 January 2022
• Designing a surficial geochemical survey
  * Anticipated target size and shape of the anomaly (or geologic target) * Ability to sample along (and/or between) key [[seismic line]]s
  6 KB (826 words) - 17:33, 25 January 2022
• Pore system shapes
  * [[Bored or burrowed]] | Pores are irregularly distributed and can be either poorly or very well connected
  4 KB (528 words) - 13:53, 4 April 2022
• EMD Tight Oil & Gas Committee
  ...d and developing plays in U.S. and international basins. Tight oil and gas or “shale” resources have been the focus of extensive development over the ...nual and commodity reports as needed; stand-in for the chair at leadership or other call-ins/meetings when the chair is unavailable; assist with other co
  4 KB (570 words) - 20:56, 6 April 2021
• Structural lead and prospect delineation
  * Storage capacity (structural degradation or enhancement effects) * Deliverability (structurally induced enhancement or degradation of [[permeability]])
  4 KB (511 words) - 18:50, 3 February 2022
• Scientific method: application to exploration
  | 6 || Accept, modify, or reject the hypothesis || Drilling another wildcat well Promoting a well to ...oblem (objective) of an exploration effort is to find large amounts of oil or gas cheaply.
  6 KB (808 words) - 15:30, 18 February 2022
• Source rock
  A '''source rock''' is a rock that is capable of generating or that has generated movable quantities of [[hydrocarbon]]s. ...rock is present. If so, then we ask, “How good is it? Will it generate oil or gas? Has it generated hydrocarbons already?” To answer these questions, w
  4 KB (569 words) - 21:38, 4 February 2022
• Hydrocarbon migration
  ...[Tertiary migration]] occurs when petroleum moves from one trap to another or to a seep.<ref name=Petersetal_2012>Peters, Kenneth E., David J. Curry, and ...he hydrocarbons laterally up [[dip]] through underlying beds to a [[trap]] or spill point. Lateral migration is also facilitated by meteoric groundwater
  6 KB (865 words) - 14:33, 6 April 2016
• Combination trap
  ...the trap belongs to one system or another is quite blurred. Traps with two or more trapping elements are called combination traps. ...e classified informally as (1) a hydrodynamically modified anticlinal trap or as (2) a hydrodynamic/anticlinal trap.
  4 KB (538 words) - 18:47, 12 April 2022
• Diagenesis
  ...of a sediment after deposition.It can have important effects in decreasing or enhancing [[porosity]] and [[permeability]].
  691 bytes (74 words) - 16:13, 22 October 2014
• Hydrofractured seal leakage
  ...enough, the sum of the [[capillary pressure]] and fluid pressure can equal or exceed the pressure needed to [[fracture]] the rock. The result is natural ...of a [[hydrocarbon column|petroleum column]] whether the seal fails during or after charging. Leakage in deeply buried accumulations occurs only where ge
  5 KB (679 words) - 17:11, 1 February 2022
• Trip
  ...le - to change a bit for example, either because the old one is worn down, or because the well is about to enter a zone whose conditions require a differ
  450 bytes (82 words) - 13:57, 12 March 2019
• AAPG Wiki:Main Page
  ...age, you will need a large image with not too many colours, low saturation or low brightness. It's easy to tweak text colour, link colour, etc if needed. ...strike the best balance between filesize (speed) and quality. For line art or other 'flat' images, use PNG for best results.
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• Static oil pressure gradient estimation
  ...]], and [[Wikipedia:Pressure|pressure]]. [[Oil and condensate analysis|Oil or condensate density]] can be estimated to useful accuracy if stock tank [[AP ...tion_fig5-7.png|Figure 1]] to determine oil density. If the GOR is unknown or if there is no dissolved gas in the oil, use the 0 line.
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• Suggested pages
  ** [[Historic plays or fields]] ...t have enough material to properly discuss a topic and need to be added to or completed.
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• AAPG Wiki:Copyrights
  For any reuse or distribution, you must make clear to others the license terms of this work. If you want to import text that you have found elsewhere or that you have co-authored with others, you can only do so if it is availabl
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• 3-D seismic data views
  ...n several ways. Vertical cuts through the data cube are called '''lines''' or '''sections'''. For marine surveys, [[in-line]] is the direction of boat mo Horizontal or subhorizontal cuts through a seismic data cube are called horizontal slices
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• Fractured membrane seal leakage
  ...:Deformation_(mechanics)#Strain|strained]], such as in stratigraphic traps or broad, gentle folds. Even relatively intact, thick seals may be fractured a ...deformation can be evaluated empirically by examining nearby accumulations or outcrops in similar tectonic settings.
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• Phi scale
  ...then calculated. Mean grain size can be expressed in either the millimeter or phi scale, but sorting must be expressed in the phi scale to maintain a sor
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• Structural exploration: location selection
  ...ons. This approach becomes critical as the structural complexity increases or the structural play concept becomes more sophisticated. ...which it is more appropriate to select a location based on technical needs or data quality rather than optimizing the economic success of the first well.
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• Abnormal hydrostatic pressure
  * [[Reservoir_quality#Compaction|Rock compaction]] or [[Rock dilation|dilation]] Abnormal pressures develop when fluid is unable to move into or out of the local [[Pore system fundamentals|pore system]] fast enough to ac
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• Migration rate calculation
  The rate of [[Hydrocarbon migration|migration]] for [[oil]] or [[natural gas|gas]] can be estimated using [[Fluid flow fundamentals|Darcy' ...cedure for calculating the [[Hydrocarbon migration|migration]] rate of oil or gas is outlined in the table below.
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• Underpressure causes
  Underpressure can be caused by [[burial]] or [[heat]] decrease. ...y [[impermeable]] rocks, it becomes underpressured by burial when faulting or downwarping occurs.
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• Displacement pressure estimation
  ...cury injection measurements || [[Overview of routine core analysis|Cores]] or [[Mudlogging: drill cuttings analysis|cuttings]] | Pore-size distribution || [[Thin section analysis|Thin sections]], cores, or cuttings
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• Inertinite
  ...maceral]] group composed of inert hydrogen-poor organic matter with little or no petroleum-generative potential. Type IV [[kerogen]] is dominated by iner
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• Seismic data: building a stratigraphic model
  The problem addressed in seismic modeling, or simulation, is calculating the seismic response ([http://wiki.seg.org/wiki/ Depth-dependent velocity and density models are needed to identify events or to create a synthetic seismogram. Velocity information can come from a vari
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• Structural exploration workflow
  ...-4.png|Figure 2]]) are most important to perform early in a frontier basin or play. More detailed analyses requiring more detailed data (right half, [[:f
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• Province, basin, system, play, and prospect
  ...in or Paris Basin. The Zagros [[fold]] belt could be a structural province or a petroleum province, not a basin. ...edimentary rocks. However, the moment petroleum is generated, biologically or thermally, a petroleum system is formed.
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• Oil-oil and oil-source rock correlation
  Correlations are comparisons of (1) oils with other oils or (2) oils with [[source rock]] extracts to determine whether a genetic relat ...osing [[migration|migration pathways]] from kitchen areas to new prospects or plays
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• Seepage activity and surficial geochemistry
  ...iles. Active seepage occurs in basins now actively generating hydrocarbons or that contain excellent migration pathways. These seeps are easily detected ...evels of hydrocarbon seepage may only be detectable near major leak points or below the zone of maximum disturbance.
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• Normal hydrostatic pressure
  ...rticle, where the fluid state (liquid or gaseous) is important, the state (or phase) is specified.
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• Energy Minerals Division
  ...helping to organize or support local society meetings, regional, national or international meetings, symposia, workshops, short courses, and field trips
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• The gravity method
  ...nding on the instrument. Other factors, such as errors in positioning data or the movement of the meter, usually cause larger uncertainties in the observ ...mmediate interest) is usually important to acquire, although other surveys or government data may be available for this purpose.
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• Relative permeability
  ...lity. Relative permeability can be expressed as a number between 0 and 1.0 or as a percent. Pore type and formation [[wettability]] affect relative perme ==Why k_ro or k_rg is less than k_ab==
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• Meteoric diagenesis
  Meteoric [[diagenesis]] is the modification of deposits at or near the surface in the [[phreatic]] and [[vadose]] zones.<ref name=Scholle
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• Top and fault seal evaluation
  * Presence or absence of [[hydrocarbon]]s ...ulations. Assessment of percent fill without the ability to risk seal (top or fault) is reduced to a statistical guessing game. They control the vertical
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• Hydrodynamics
  Hydraulic head (H_w) is the height or elevation above a given subsurface point at which a column connected to a b * H_w = height above P (ft or m)
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• Carbonate
  ...and XF methods|X-Ray Diffractometry]]. Carbonates more rich in calcite and/or aragonite are called [[limestone]]. Carbonate rocks composed mainly of the
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• Basin framework
  The particular study area, whether only a part of a basin or an entire basin itself, should be identified on a large-scale geographic ma ...ploration for hydrocarbons within each of these subbasins. We can prepare (or locate) a map showing total sediment thickness and the distribution of hydr
  4 KB (518 words) - 16:42, 18 February 2022
• Structural domains
  ...region with similar structural properties (e.g., similar [[fold]] vergence or style, shortening, uplift, faulting style, etc.). * Satellite imagery and/or aerial photography (See [[Remote sensing]].)
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• Magnetics: total intensity and residual magnetic maps
  ...al intensity maps show larger scale geologic features, such as basin shape or anomalous rock types deep within the basement. ...of techniques, including running averages, polynomials, low-pass filters, or [http://wiki.seg.org/wiki/Dictionary:Upward_continuation upward continuatio
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• Offshore exploration and exploitation
  ...ect searching for the resources using geophysical methods: Magnetic survey or register, gravimetric survey, and seismic survey. === Magnetic survey or register ===
  5 KB (708 words) - 22:00, 10 April 2019
• Hydrocarbon column: calculation of maximum height
  or, in mixed units, * ''h'' = thickness of the hydrocarbon column, ft or m
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• Hydrodynamic traps: mapping
  ...lp outline areas where hydrodynamic gradients may have created, destroyed, or modified traps. # Look for [[permeability]] barriers or hydrocarbon-free water levels using pressure-depth plots.
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• Quantitative biostratigraphy
  ...rray of data points, a preferred overall correlation can be defined by one or more line segments. Points falling on the line(s) of correlation are interp ...are based on the sequence of events and not on the stratigraphic intervals or distances between them.
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• Midale seal capacity and trap type
  ...lumn of oil shared by Weyburn and Steelman. Weyburn is a hydrodynamic trap or a combination hydrodynamic–[[stratigraphic trap]]. ...fferent pore types and pore geometries. For an explanation of each diagram or chart see Chapter 9 in ''Exploring for Oil and Gas Traps''.
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• Cracking
  ...molecules break apart into smaller molecules during burial [[maturation]] or in a refinery. [[Kerogen]] in source rocks and oil in reservoirs are cracke
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• Subregional and local pressure compartments
  ...der) [[pressure compartments]] can be found within normal pressure regimes or [[regional pressure compartments]]. ...outside the bioherm. The bioherm, then, is a pressure compartment that may or may not be abnormally pressured. Other geological features that may form lo
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• Microbial gas
  Also called marsh gas or biogenic gas; typically greater than 99% [[methane]] produced by methanogen
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• Remote sensing
  * Side-looking airborne radar (SLAR) and/or sonar ...ltitude data or by using a contractor as an intermediary for obtaining and/or processing the imagery
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• Procedure for geometrical analysis
  ...itional sequences]], [[Systems_tracts_and_trap_types|systems tracts]], and/or [[Hierarchy of sequences|parasequence]]s. Recognizing these correlation fea ...ized by onlap of strata deposited in fluvial, deltaic, or nearshore marine or peritidal environments.<ref name=ch21r48>Weber, L. J., J. F. Sarg, and F. M
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• Evaporite
  ...re minerals produced by the evaporation of water. This may occur in marine or nonmarine settings. The common evaporite minerals associated with petroleum
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• Regional pressure compartments
  ...tem overlying one or more hydraulic compartments whose pressures are above or below the normal static water pressure.<ref name=ch05r14>Powley, D., E., 19 ...surface (normally pressured hydraulic system). The '''top seal''' is more or less horizontal and usually cuts across stratigraphic units. It forms where
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• Siliceous microfossils
  ...recrystallized, preserved in nodules or concretions, or replaced by pyrite or calcite. ...e and nonmarine environments. Marine diatoms range from [[Upper Jurassic]] or [[Lower Cretaceous]] to [[Holocene]] and are particularly useful for age an
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• Tectonic inversion
  ...normal [[fault]]s are reactivated by [[compression]] (positive inversion), or where reverse faults are reactivated by [[extension]] (negative inversion).
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• Depositional trap regime
  ...thology. Where described, trap styles can be listed based on the lithology or composition of the sealing rocks. The outline below shows the classes and s ...servoir distribution. || colspan = 2 | ''Sandstone reservoirs''; Partially or completely isolated by seal.
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• Basement fault blocks and fault block patterns
  ...These zones of weakness are periodically reactivated by tectonic stresses or gravitational loading. Consequently, they have influenced depositional patt ...d terrains and demonstrate that the lineations fall into multiple parallel or subparallel sets of varying [[strike]] directions. These overlapping [[frac
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• Fishing
  * Bridging off by swelling formations or a collapsed hole. ...material, to sidetrack around the original material, to abandon the well, or to attempt to complete in a shallower zone. Because all but the first of th
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• Sandstone permeability estimation from cuttings
  | I || Rocks with pores capable of producing gas without natural or artificial fracturing. ...h pores capable of producing gas with natural or artificial fracturing and/or interbedded with type I rocks.
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• Waterflooding
  ...of oil and free gas by water. In waterflooding, water is injected into one or more injection wells while the oil is produced from surrounding producing w ...invasion or vertical sweep efficiency (''E''_V) and the pattern or areal sweep efficiency (''E''_P).
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• True resistivity determination
  ...contain formation water only ([[water saturation]] [S_w] = 100%) or [[formation water]] and hydrocarbons (S_w < 100%). Using a valid ...filtrate|resistivity (R_mf)]] is either greater than, less than, or equal to R_t and can distort deep resistivities. Distortions to r
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• Governance
  * Avoid complexity or obscurity
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• Postaccumulation cementation
  ...a petroleum phase may retard [[diagenesis]] in an [[accumulation]], sooner or later [[reservoir quality]] decreases with increasing age and burial.<ref n ...y]]). In low-permeability [[tight gas reservoirs: evaluation|tight sands]] or carbonates, the capillary [[displacement pressure]] in the reservoir rock m
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• Surficial geochemical interpretation guidelines
  ...one or more survey lines may indicate the location of discrete structural or stratigraphic targets within the survey area. If the basin or play is characterized by predominantly vertical migration, then the correla
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• Petroleum source rock formation
  ...hesis and nutrient supply. Under appropriate conditions, phytoplankton and/or algal/bacterial mats form in lacustrine, estuarine, and marine paleoenviron ...cted sediments at depths below wave base, in stagnant waters where density or temperature-stratified water columns form, and in other areas where oxygen
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• Limitations of oil correlations
  ...similar thermal maturities. Except in cases of extreme overmaturity of one or more of the samples, these problems can usually be overcome by an experienc ...or differences in technique between laboratories. The amount of acceptable or “normal” difference varies greatly, depending on the range of maturitie
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• Activation energy
  ...for chemical transformations, commonly expressed in kilocalories per mole or kilojoules per mole. Activation energy distributions are used in [[maturati
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• Early carbonate diagenesis
  Early [[diagenesis]] occurs at the surface or in the shallow subsurface. It is usually responsible for much of the cement ...ater flow combined with other factors result in precipitation of aragonite or magnesium (Mg) calcite.
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• Petroleum
  ...s composed mainly of hydrogen and carbon and found in the gaseous, liquid, or solid state in the Earth; includes hydrocarbon gases, bitumen, migrated oil
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• AAPG Wiki:Terms of use
  ...any changes to articles, and has full scientific authority over acceptance or rejection of alterations and deletions.
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• Using analogs to identify critical elements
  ...luck finding rabbits if he did not understand their habits—where they live or what and when they eat. In the same way, we learn about oil and gas fields ...trap to work. When we study local analog fields within a region or basin, or perhaps in a similar productive setting in another part of the world, we ca
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• Seismic data and mapping structure
  ...d|3-D data]]. The recipes described on the pages that follow apply to hand or computer work.
  2 KB (320 words) - 19:10, 27 January 2022
• Parasequences (fourth- and fifth-order sequences)
  ...000–200,000 years in duration) to be the building blocks of most reservoir or field studies. ...l]] extent and forms in response to (for example) [[tidal flat]] migration or [[Deltaic environments|delta]] lobe shifts. Episodic parasequences are of v
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• Natural gas occurrence
  ...ional gas accumulations as "continuous accumulations . . . that exist more or less independently of the water column," and discusses several methods for ...st have produced gas profitably in the United States for at least a decade or two and will undoubtedly become major sources of energy in the decades to c
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• Trap classification
  ...ap generally shares enough similarities with other traps in the same basin or in other basins that traps may be classified. The classification chosen dep ...onsequently, a classification scheme such as that used to organize a stamp or coin collection might be more useful, especially one in which a variety of
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• Measurement while drilling
  ...igure 1]]). Electrical energy for the system is provided by a battery pack or generated by a small turbine. ...rs are transmitted through the mud as positive or negative pressure pulses or as a continuous, fixed-frequency pressure wave.
  8 KB (1,083 words) - 21:18, 19 January 2022
• Seismic attributes in geological interpretation
  ...can take the form of dividing the attribute by either the actual isochron or by the number of time samples in the interval. Although this normalization ...the software vendor to provide well-written documentation, either on paper or online, that explains the mathematical calculation involved in generating t
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• Rig personnel
  ...e rig 24 hr a day, the crew(s) usually commute and work 8- or 12-hr shifts or tours. ...ed. A representive from the client company called the ''drilling foreman'' or ''company man'' is typically present on the rig. The company representive i
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• Sidewall coring
  ...ned in zones of interest using gamma logs or SP logs as guides. Percussion or rotary drilled samples provide small bits of formation material, suitable f ...data. Also, percussion sidewall core recovery tends to be low in very hard or fractured rock.
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• Petroleum system: geographic, stratigraphic, and temporal extent
  ...then the evidence that a petroleum system existed is absent. An incomplete or just completed petroleum system lacks a preservation time. ...stem. The stratigraphic extent is from below the pod of active source rock or the petroleum of the discovered accumulations in the system, whichever is d
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• Calcareous microfossils
  ...ure and high hydrostatic pressure, however, calcareous remains are largely or completely dissolved. The depth below which this occurs, which varies in di ...ular organisms (protists) that secrete a rigid calcite or aragonite shell (or test). Fossils of these forms are found in sediments of brackish to marine
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• Hydrocarbon expulsion, migration, and accumulation
  ...ding the pore pressure of the adjacent carrier bed. Oil or gas is expelled or “squeezed” into the carrier bed due to the differential pressures betwe ...density differential of the hydrocarbons and the formation water. The oil or gas migrates in filaments through the pore system of the aquifer as long as
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• Magnetotellurics
  ...tantly, can be used in places where seismic data collection is impractical or gives poor results. This is the same physical parameter that is measured in ...high-resistivity layers. It is difficult for MT to resolve more than three or four subsurface layers.
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• Migration pathway
  ...tervals. It leaves either no trace or a trace that is continually modified or destroyed by later events. Effective [[hydrocarbon migration]] occurs along ...this pathway, petroleum will accumulate until the trap is full and spills, or leaks, any additional migrating petroleum.
  6 KB (889 words) - 16:50, 29 March 2022
• Crude oil
  ...ndant compounds in crude oils, but they also contain nitrogen, sulfur, and/or oxygen (NSO) compounds and variable concentrations of trace elements, such
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• Unconformity
  ...record of geological time, during which deposition had ceased and folding or faulting occurred, the lower strata tilted, and then deposition resumed.]]
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• Carbonate porosity formation and preservation
  ...gins with good [[porosity]] and [[permeability]], either from depositional or early diagenetic processes, has a better chance of retaining those qualitie ...ric selective (fluid flow through interparticle or intercrystalline pores) or nonfabric selective (compaction).
  5 KB (708 words) - 17:27, 5 December 2023
• Mudlogging: drill cuttings analysis
  ...of lithology to wireline logs, and other special geological, geophysical, or engineering analyses (see [[Show evaluation]]). Some of the activities that ...an be obtained and used to evaluate prospective reservoir zones and casing or kick-off points.
  10 KB (1,482 words) - 15:25, 24 January 2022
• Rate of penetration
  ...n be expressed as either distance drilled per unit of time (feet per hour) or time per distance drilled (minutes per foot). ..., that is wrapped around a drum. The drum rotates one revolution in 8, 12, or 24 hr. To record depth, a small cable is run from the geolograph to the top
  7 KB (1,049 words) - 19:02, 20 January 2022
• Formation fluid pressure from drill stem tests
  A drill-stem test, or DST, is the most common method to measure reservoir pressure. DSTs are the * During '''run-in or run-out periods''', [[drilling fluid]] flows through ports in the tool wall
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• Sequences during low-amplitude, high-frequency cycles
  ...les of sea level (see [[Hierarchy of sequences]]) change because of little or no polar ice, and they tend to have high frequency and low amplitude. Read< * Cycles of 20 k.y. or less sometimes superimposed on 100- and 400-k.y. cycles
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• Fieldwork risk assessment
  As used here, ''risk'' is exposure to an undesirable outcome or chance at loss. In the case of exploration, it is exposure to the occurrenc The final step is to determine the information needed to reduce or further assess key risks. This step promotes free thinking and lets us visu
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• Macroseepage vs. microseepage in surficial geochemistry
  ...tion of faults, fractures, and outcropping [[Unconformity|unconformities]] or carrier beds. These visible seeps have led to the discovery of many of the ...ally detectable volatile or semivolatile hydrocarbons in soils, sediments, or waters. These invisible seeps are recognized only by the presence of anomal
  6 KB (754 words) - 22:07, 24 January 2022
• Predicting carbonate reservoir location and quality
  ...lity]] is defined as the “ability of a reservoir to store and transmit oil or gas.” We also can include the thickness and lateral extent as aspects of ...er#Sediment_supply_rate_and_facies_patterns|progradational, aggradational, or retrogradational patterns]] within sets. Make isopachs of systems tracts us
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• Correlation and regression analysis
  ...decrease as the other, y, increases or decreases, in a straight-line trend or relationship.<ref name=Draper_etal_1966>Draper, N. R., and H. Smith, 1966, ...tive for simple linear correlation when the number of samples is small and/or the joint distribution of the two variables is not simple. Multiple correla
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• Core handling
  ...is pulled. Every effort should be made to prevent the core from weathering or changing if s fluid contents. Speed is important when handling hard rock to ...d marking surface. Do not wash the core. Washing changes the fluid content or [[wettability]] and impacts the subsequent analysis.
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• Capillary pressure (Pc): buoyancy, height, and pore throat radius
  ...ta generated by these techniques cannot be compared directly to each other or to reservoir conditions. Below, we demonstrate how to convert pressures mea ...convert P_c to [[buoyancy pressure]], pore throat size (''r''), or [[hydrocarbon column]] height (''h''′). Assume water-wet conditions in th
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• Water saturation distribution in a reservoir
  BVW and Buckles plots can be confusing in interbedded lithologies or in areas where [[Lithofacies|facies]] changes occur because of changing por ...ng zone. Variations reflect different [[Reservoir quality|pore types]] and/or height above [[Free water level|free water]]. An S_w–depth plot
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• Seismic data display
  ...the type of anomaly you are trying to discern, such as porosity, gas zone, or facies changes. This allows the correct selection of a data processing flow ...reverse the display convention. Then the display is said to be ''reverse'' or ''negative polarity''.
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• Sequences during moderate-amplitude, high-frequency cycles
  Fourth- or fifth-order moderate sea level cycles (20–50 m) occurred when global clim * Abundant siliciclastics in bases and/or tops of sequences of land-attached platforms
  5 KB (674 words) - 21:22, 6 April 2022
• AAPG Wiki:Moderation
  *Too rigid or bureaucratic moderation can increase volunteer cost. ...specific subject matter expertise that would review articles independently or collaboratively and reach agreement to approve/flag articles
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• Carbonate facies
  ==Platform or ramp development==
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• Taphonomy and provenance
  ...difficult to recognize in [[Mudlogging: drill cuttings analysis|cuttings]] or even in cores and outcrops. ...anisms. A taphonomic study can help identify variations in ''provenance'', or source area, of fossil-bearing sediments.<ref name=ch17r55>Lawrence, D. R.,
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• Quartz
  ...many varieties—true quartz in the form of megaquartz, chert, microquartz, or chalcedony and various other forms of silica, mainly opal (opal-A and opal- ...dy and colored varieties occur where crystals are especially rich in water or mineral inclusions. In thin section, these colors are rarely seen, although
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• Fault seal behavior
  ...al behavior are (1) cross sealing or cross leaking and (2) [[dip]] sealing or dip leaking. '''Cross seal and leak''' refers to the ''[[lateral]]'' commun A fault does not simply seal or leak; many variations exist:
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• Pressure prediction: analysis of mud weights
  ...rt a pressure close to the expected pore pressure. When drilling mud kicks or [[Pressure_detection#Drilling_problems_with_overpressured_reservoirs|blows When the drilling mud kicks or blows out, pore pressure can be calculated by using the following formula:
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• Structural fairway prospectivity
  Certain [[structural domains]] or specific portions of those domains provide the greatest opportunities for e * Tectonic [[overburden]] or denudation
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• Oil and gas contracts
  ...angements. The most common types of contracts used are farm-outs-farm-ins, or well trade agreements, and joint operating agreements. ...ore than drill a well, including performing geological and seismic studies or paying a cash consideration for past costs incurred by the farmor.
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• How faults control trap fill and migration pathways
  ...g sealing faults. A [[fault]] can act as a barrier to (1) all hydrocarbons or (2) some of the hydrocarbons, allowing a limited volume to migrate. It can ...ly complex. Traps in this setting can have widely different migration/fill or [[Calculating charge volume|charge]] risks, depending upon [[fault seal beh
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• Microfossils in exploration
  ...ratigraphic]] or [[Paleoenvironmental analysis|paleoenvironmental]] range, or too poorly understood to be broadly useful in industrial application are no ...principal microfossil groups based on the composition of the shell (test) or hard parts. The table below shows the principal microfossil groups.
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• Toe
  The end point in a wellbore of the lateral section or sections is called the toe.
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• Seismic facies analysis
  ...ated with 90&deg; Ricker wavelets of 20-, 35-, and 80-Hz peak frequencies (or 26-, 45.5-, and 104-Hz predominant frequencies, respectively). No noise is ...cedure to analyze seismic facies from a grid of sections (vertical) of 2-D or 3-D [[seismic data]] (modified from <ref name=ch21r31 />).
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• Reducing exploration risk
  A play is one or more prospects that may define a profitable accumulation of undiscovered pe ...eum system case study is completed. As the case study develops, an idea(s) or play(s) that involves this petroleum system will occur to the investigator.
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• Main Page/News
  * [mailto:[email protected] Email matt], or call him on +1-902-980-0130
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• Diagenesis: information from petrology
  | Oil-filled fluid inclusions in reservoir or carrier beds || Indicates migration pathways and absolute timing of migrati ...ng of [[leakage]] || [[Hydrocarbon column|Column]] height may be small and/or [[Dip|updip]] (spilled) accumulations may exist
  4 KB (544 words) - 21:38, 4 February 2022
• Oil correlation case histories
  ...ut and not from secondary processes such as [[maturation]], [[migration]], or [[biodegradation]].
  964 bytes (130 words) - 16:32, 24 June 2015
• Carbonate diagenetic stages
  ...structures of skeletal grains or within nonskeletal grains such as pellets or ooids. ...al deposition. All the porosity that forms during this stage is diagenetic or secondary in origin. Diagenetic processes are related to changes in water c
  6 KB (727 words) - 19:06, 6 April 2022
• Geothermal gradient
  ...erature with depth in the Earth, commonly in degrees Celsius per kilometer or degrees Fahrenheit per 100 feet. Gradients are sensitive to basal heat flow
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• Hydrocarbon pressure gradient: plotting
  # Determine a pressure above or below the measured depth point. The table below lists the steps for determi ## Pick a depth above or below the measured point.
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• Oil correlation
  Correlations are comparisons of two or more samples based on the physical and chemical properties of those samples ...termine whether a genetic relationship exists among a group of oil samples or between an oil and a proposed [[source rock]]. Positive correlations are al
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• Seismic data preparation for mapping
  # Compute a synthetic seismogram for each online well with a sonic or [[density log]]. ...l_seismic_profiles|vertical seismic profile (VSP)]], synthetic seismogram, or time-stretched logs.
  7 KB (1,064 words) - 19:11, 27 January 2022
• Predicting reservoir drive mechanism
  * High recovery factor (50% or more) * Water-free production (or relatively minor)
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• Workovers
  A ''workover'' is any operation done on, within, or through the wellbore after the initial completion. Although proper drilling ...uction casing, even smaller equipment is run for completion and production or injection purposes. [[:file:workovers_fig2.png|Figure 2]] illustrates the t
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• Molecular fossils
  ...ocks, sediments, fossils, or oils that can be reliably associated with one or a few biotic antecedents. The term “molecular fossil” is limited here t ...or in oil provides information about the paleoenvironment of the sediment or source.
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• Sandstone provenance and characterization
  ...them and to make them deposited. That’s why we can found the sand deposit or sandstone almost in everywhere. ...s are minerals that are not formed on the environment during sedimentation or sedimentation occurs. These minerals come from rocks that have undergone tr
  10 KB (1,524 words) - 15:29, 14 March 2016
• Influence of depositional environment on sandstone diagenesis
  ...ble. The energy level of depositional environments affects sorting by size or hydraulic equivalence and consequently produces different detrital mineral ...ays that are products of disaggregation. Reworked sands, such as shoreline or tidal sands, are more quartzose.
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• Sea level cycles and carbonate diagenesis
  ...er diagenesis does not occur or is greatly reduced because there is little or no pore-water movement. High-frequency sea level cycles (fourth or fifth order) cause the cyclical migration of the vadose, freshwater phreati
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• Production histories
  ...nduct a project, well testing and simulation can be used to supplement and/or upgrade the quality of forecasts generated by production histories (see [[P ...it does not anticipate changes in performance due to operating conditions or changes in reservoir behavior (for more on decline curves, see [[Reserves e
  11 KB (1,656 words) - 18:41, 20 January 2022
• Picking horizons in 3-D data
  ...however, assumes that a horizon is locally very smooth and perhaps linear (or planar in two dimensions) between control points. If this assumption is vio ...utopicking is quite simple. The interpreter places seed picks on lines and/or cross-lines in the 3-D survey. These seed points are then used as initial c
  8 KB (1,155 words) - 19:12, 27 January 2022
• Well planning
  * Straight, slanted, or [[Well types#Horizontal well|horizontal well]] ** Hot wire or flame ionization detection (FID) chromatograph
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• Petrophysical analysis of lithofacies
  ...strongly influenced by its environment of deposition. Diagenesis can alter or completely change the original pore space of a rock, especially for carbona ...ty]] data. Categorize each flow unit by port type as mega-, macro-, meso-, or microporous.
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• Geological fieldwork benefits
  ...vance specific business recommendations on how to proceed with exploration or manage technical risk. ...e an explorationist has in his or her work. In presentations to management or investors, that “been-there” confidence shows through.
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• Measuring displacement pressure using mercury injection
  ...orcing mercury into the pore space of a sample ([[Core description|cores]] or [[Mudlogging: drill cuttings analysis|cuttings]]) and measuring the percent ...nced plateau along which saturation rapidly increases. The pressure at 10% or 40% saturation gives a similar P_d.
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• Top seal displacement pressure
  * θ = contact angle or [[wettability]], degrees ...PG Bulletin, vol. 59, no. 6, p. 939–956.</ref> If the wetting phase is oil or gas rather than water, the contact angle can range from 0 to 180°. Not all
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• Hydrology and sandstone diagenesis
  ...g water moves chemical components through pores and causes either leaching or cementation of grains. Diffusion also moves chemicals in and out of rocks, ...waters. Deeper infiltration occurs from (a) eustatic sea level changes and/or (b) tectonic elevation of basin margins.
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• Cross-sealing fault
  ...oss sealing if it juxtaposes sands with different hydrocarbon contacts and/or different free water levels. ...oss sealing if it juxtaposes sands with different hydrocarbon contacts and/or different free water levels, as illustrated in [[:file:evaluating-top-and-f
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• Oil shale
  ...ry petroleum solvents, from which substantial amounts of synthetic oil and/or gas can be extracted by heating it to a sufficiently high temperature, a pr ...the development of new mining and processing technology for the oil shale or a substantial increase of the price of oil may make oil shales with lower o
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• Sequence stratigraphy analysis
  ...ted and can be preserved. Organic-rich rocks are colored dark gray, black, or chocolate brown, reflecting their relatively high volumetric ratio of organ ...hic sequences. Most woody coals generate gas, although some bear the algal or bacterial components that can generate oil. Gas-prone terrestrial organic m
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• Seismic interpretation
  ...a, proper interpretation still requires that the interpreter draw upon his or her geological understanding to pick the most likely interpretation from th ...interpreter to study. The first is the time of arrival of any reflection (or refraction) from a geological surface. The actual depth to this surface is
  10 KB (1,520 words) - 18:48, 21 January 2022
• Elemental parameter data for oil–oil and oil–source rock correlations
  ...e below. Therefore, unless the maturity levels of all samples are similar, or unless some correction for maturity is made, sulfur content can be misleadi ...cs), lighter nonhydrocarbons (NSOs [nitrogen, sulfur, oxygen], [[polar]]s, or [[resin]]s), and heavier nonhydrocarbons ([[asphaltenes]]). Oils with terre
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• Magnetics: petroleum exploration applications
  ...can occur along [[basement]] block boundaries and (2) subtle fault offsets or other structural and stratigraphic features. The locations of the basement ...m well data. However, on overseas projects or in frontier areas, the best (or only) data available may be 2-D seismic surveying. In either case, the proc
  9 KB (1,274 words) - 17:59, 24 January 2022
• Density-neutron log porosity
  ...mates of porosity are possible with the combination than using either tool or sonic separately because inferences about lithology and fluid content can b ...t bulk density to porosity using charts in a log interpretation chartbook, or calculate porosity from bulk density using this equation:
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• Mudlogging: gas extraction and monitoring
  ...tection of a gas influx will give rig crews time to respond to toxic gases or a potential blowout condition. Accurate gas data recorded during drilling i ...This aids in identifying the types of hydrocarbons in place (that is, oil or gas).
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• Wellsite safety
  ...ry or death. The wellsite is a hostile environment, often either very cold or very hot, wet, and slippery. Hazards include heavy equipment being moved ar ...his practice may include having personnel donning life jackets, air packs, or survival suits and assembling at the escape boat. Some drills include board
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• Factors that cause migration
  ...me time during the migration process. Each factor produces energy from one or more sources. The table below lists these factors and their corresponding e | Presence of oil or gas
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• Depositional sequence identification
  A depositional sequence is bounded by [[Unconformity|unconformities]] or the correlative conformity. It is subdivided by internal surfaces of [[tran ...[[Biostratigraphic correlation and age determination#Changes in abundance or composition|abundance patterns]] that may suggest depositional sequences.
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• Strain analysis of top seals
  ...nt seep]] in the Santa Barbara Channel, California, is leaking 50–70 bbl/d or more than 25 billion bbl/m.y.<ref name=ch10r95>Wilkinson, E., R., 1971, Cal
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• Reflection configuration patterns
  ...ain. Divergent reflectors suggest lateral variations in depositional rates or progressive tilting of a depositional surface. [[:file:exploring-for-strati ...coarse-grained [http://www.merriam-webster.com/dictionary/fluvial fluvial] or [[turbidite]] channel fills. Contorted features may be shale-prone [[debris
  5 KB (592 words) - 17:46, 4 February 2022
• Kickoff point
  The kickoff point (KOP) is the location in a vertical wellbore or inclined section of a slant well where directional drilling operations comm
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• Petroleum system
  ...from one pod of active [[source rock]] and occurs in [[show]]s, [[seep]]s, or [[accumulation]]s;<ref name=Magoonanddow_1994>Magoon, L. B., and W. G. Dow, ...nd processes are known to occur or are thought to have a reasonable chance or probability to occur.
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• Seismic data acquisition on land
  ...ly provide adequate accuracy, given sufficient control. However, in remote or previously unsurveyed areas, satellite stations may be necessary to provide ...acord) ([[:file:seismic-data-acquisition-on-land_fig1.png|Figure 1]]), gas or air guns, weight drop mechanisms, vibrator systems ([[:file:seismic-data-ac
  10 KB (1,389 words) - 16:20, 20 January 2022
• Interpreting gravity measurements
  ...ns as geologically unreasonable, it is best to start with good constraints or to test reasonable geologic questions. Gravity is not as good at depth-to-basement or depth-to-density anomaly estimations as other [[geophysical methods]]. Thou
  5 KB (725 words) - 18:00, 24 January 2022
• Migration rate
  ==Hydrodynamics or compaction transport rate== ...rate. In practice, however, the additional force supplied by hydrodynamics or compaction is largely counterbalanced by capillary forces and relative [[pe
  6 KB (877 words) - 19:33, 14 February 2022
• Surface geochemical exploration: assumptions
  ...m/data/bulletns/1982-83/data/pg/0067/0006/0900/0932.htm Predictions of oil or gas potential by near-surface geochemistry]: AAPG Bulletin, vol. 67, p. 932 ...ncreasingly difficult as the geology becomes more complex. The geochemical or microbial anomaly at the surface represents the end of a petroleum [[migrat
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• Sampling for paleontology
  ...nt of drill pipe added to the drill string (i.e., every [[length::30 ft]], or 9 m) and represents an amalgamated sample of the rocks penetrated in that i Although the use of cuttings is less precise than conventional or sidewall cores, this method of sampling can yield surprisingly robust paleo
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• Dip
  ...dicular to strike; this requires that a strike be given), 4 SE (likewise), or 4 65SE (dipping 4 degrees in a 65SE direction; this by inference gives the
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• Paleoclimatology
  ...hy]] provides the only practical means to demonstrate the contemporaneity, or lack of it, of contrasting climates. ...distinctive climates or environments may have distinctive characteristics, or '''morphologies'''. Recognizing these features in fossils can provide infor
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• Sea level cycles and climate
  ...ly in different regions during icehouse or greenhouse periods. The aridity or humidity of a region strongly affects carbonate deposition and [[diagenesis ...ater carbonate settings where the photic zone extends to [[length::100 m]] or deeper. Tropical carbonate faunal assemblages strongly depend on light, whi
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• Lateral
  Lateral is a term applied to either a single branch or individual multiple ([[multilateral well|multilateral]]) branches off the v
  1 KB (185 words) - 13:56, 17 March 2016
• Sea level cycles and carbonate sequences
  ==Parasequence sets or systems tracts== ...#Sediment_supply_rate_and_facies_patterns|retrogradational, aggradational, or progradational patterns]]. A parasequence set approximately corresponds to
  7 KB (989 words) - 20:45, 6 April 2022

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