Changes

  | part    = Predicting the occurrence of oil and gas traps

  | part    = Predicting the occurrence of oil and gas traps

  | chapter = Exploring for structural traps

  | chapter = Exploring for structural traps

  | frompg  = 20-1

  | frompg  = 20-46

  | topg    = 20-70

  | topg    = 20-47

  | author  = R.A. Nelson, T.L. Patton, S. Serra

  | author  = R.A. Nelson, T.L. Patton, S. Serra

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch20/ch20.htm

  | link    = http://archives.datapages.com/data/specpubs/beaumont/ch20/ch20.htm

==Prospect identification==

==Prospect identification==

A structural lead becomes a prospect once we determine that the major components of the hydrocarbon system have sufficient probabilities of success in contributing to an economic accumulation of hydrocarbons in the structure. In the table below are examples of some structural technical issues to consider when assessing the [[petroleum system]] relative to a structural lead. Many companies use a mixture of these issues to assess exploration risk, employing various numerical approaches.

A structural lead becomes a prospect once we determine that the major components of the hydrocarbon system have sufficient probabilities of success in contributing to an economic [[accumulation]] of hydrocarbons in the structure. In the table below are examples of some structural technical issues to consider when assessing the [[petroleum system]] relative to a structural lead. Many companies use a mixture of these issues to assess exploration risk, employing various numerical approaches.

{| class = "wikitable"

{| class = "wikitable"

|-

|-

! Element

! Element || Factors Defining the Structural Prospect

! Factors Defining the Structural Prospect

|-

|-

| Trap

| Trap ||

| * Trap integrity (certainty of dip closure; integrity of the closure throughout the evolution of the structure) <br />* Area/volume under closure (present closure; structural closure during migration)

* Trap integrity (certainty of [[dip]] closure; integrity of the closure throughout the evolution of the structure)  

* Area/volume under closure (present closure; structural closure during migration)

|-

|-

| Seal

| Seal ||

| * Integrity of seals (continuity and integrity of top seal; integrity and capacity of fault seals)

* Integrity of seals (continuity and integrity of top seal; integrity and capacity of fault seals)

|-

|-

| Reservoir

| Reservoir ||

| * Storage capacity (structural degradation or enhancement effects)  <br />* Deliverability (structurally induced enhancement or degradation of [[permeability]])  <br />* [http://wiki.seg.org/wiki/Dictionary:Anisotropy Anisotropy] (flow anisotropy due to faults, folds, or fracture facies variability)  <br />* Heterogeneity (local enhancement or degradation; fault isolation or compartmentalization)  <br />* Pressures (structurally induced overpressures)

* Storage capacity (structural degradation or enhancement effects)   

* Deliverability (structurally induced enhancement or degradation of [[permeability]])   

* [http://wiki.seg.org/wiki/Dictionary:Anisotropy Anisotropy] (flow anisotropy due to faults, folds, or [[fracture]] facies variability)   

* Heterogeneity (local enhancement or degradation; fault isolation or compartmentalization)   

* Pressures (structurally induced overpressures)

|-

|-

| Source facies

| Source facies ||

| * Maturation (structural overburden considerations; tectonic subsidence and uplift effects considered)

* [[Maturation]] (structural overburden considerations; tectonic subsidence and uplift effects considered)

|-

|-

| Expulsion/ migration

| Expulsion/ migration ||

| * Structural pathways (charge areas have been in effective communication with prospects)  <br />* Structural gathering areas (sufficient volumes of migrating hydrocarbons captured and diverted into appropriate pathways)  <br />* Timing (structural pathways effective throughout generation/migration event)

* Structural pathways ([[Calculating charge volume|charge]] areas have been in effective communication with prospects)   

 

* Structural gathering areas (sufficient volumes of migrating hydrocarbons captured and diverted into appropriate pathways)   

* Timing (structural pathways effective throughout [[Petroleum generation|generation]]/migration event)

|}

|}

The following data sources and techniques can help us assess some of these technical issues:

The following data sources and techniques can help us assess some of these technical issues:

* Outcrop studies (interpretive analogs)

* [http://www.merriam-webster.com/dictionary/outcrop Outcrop] studies (interpretive analogs)

* Structure section balancing (structural geometry)

* Structure section balancing (structural geometry)

* Palinspastic restoration (migration pathways; paleostructure)

* Palinspastic restoration (migration pathways; paleostructure)

* Dipmeter and FMS analysis (structural geometry)

* [[Dipmeter]] and FMS analysis (structural geometry)

* Detailed seismic, 2-D and 3-D (structural geometry)

* Detailed seismic, 2-D and 3-D (structural geometry)

* [[Modeling]] studies (seismic; theoretical; physical; interpretive analogs)

* [[Modeling]] studies (seismic; theoretical; physical; interpretive analogs)

* Hydrocarbon migration pathway analysis

* [[Hydrocarbon migration]] pathway analysis

* Fault-seal studies (trap integrity)

* Fault-seal studies (trap integrity)

* Core analysis (fracture potential)

* Core analysis ([[fracture]] potential)

* Mechanical testing of rock (fracture potential)

* Mechanical testing of rock (fracture potential)

* Petrofabric analysis

* Petrofabric analysis

* Fracture analysis

* [[Fracture analysis]]

* Curvature analysis (fracture potential)

* Curvature analysis (fracture potential)

* Mechanical testing (fracture potential)

* Mechanical testing (fracture potential)

* Special seismic processing and velocity analysis (e.g., prestack migration; amplitude vs. offset)

* Special seismic processing and velocity analysis (e.g., prestack migration; amplitude vs. [[offset]])

==When a lead becomes a prospect==

==When a lead becomes a prospect==

Once we determine that the risk in drilling for hydrocarbons on the structural anomaly is acceptable, the lead qualifies as a prospect. The next problem confronting the explo-rationist is picking an appropriate location on the prospect.

Once we determine that the risk in drilling for hydrocarbons on the structural anomaly is acceptable, the lead qualifies as a prospect. The next problem confronting the explorationist is picking an appropriate location on the prospect.

==See also==

==See also==

* [[Workflow to find a prospect]]

* [[Structural exploration workflow]]

* [[Tectonic setting]]

* [[Tectonic setting]]

* [[Structural domains]]

* [[Structural domains]]

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Predicting the occurrence of oil and gas traps]]  

[[Category:Exploring for structural traps]]

[[Category:Exploring for structural traps]]