Changes

Clinoforms occur at a wide range of spatial scales, from large, basinward-dipping surfaces at the shelf-slope margin, to smaller surfaces associated with progradation of deltaic and shoreface systems across the shelf (e.g., Helland-Hansen and Hampson<ref name=HHH>Helland-Hansen, W., and G. J. Hampson, 2009, Trajectory analysis: Concepts and applications: Basin Research, v. 21, no. 5, p. 454–483, doi: 10.1111/j.1365-2117.2009.00425.x.</ref>). This study focuses on developing a surface-based approach to represent clinoforms at any lengthscale in reservoir models, with emphasis on clinoforms produced by the progradation of deltaic, barrier-island, and strandplain shorelines, which are typically up to a few tens of meters in height. The 3-D geometry and spatial arrangement of shoreline-scale clinoforms reflect in large part the process regime under which they were deposited (e.g., Galloway<ref name=Glwy>Galloway, W. E., 1975, Process framework for describing the morphological and stratigraphic evolution of deltaic depositional systems, in M. L. Broussard, ed., Deltas, models for exploration: Houston, Texas, Houston Geological Society, p. 87–98.</ref>). Fluvial-dominated deltas exhibit a hierarchy of point-sourced, teardrop-shaped sediment bodies that are fed via a downstream branching network of distributary channels. From small to large lengthscales, this hierarchy consists of mouth bars, mouth-bar assemblages, and delta lobes<ref name=Bhttchry2006>Bhattacharya, J. P., 2006, Deltas, inH. W. Posamentier, and R. Walker, eds., Facies models revisited: SEPM Special Publication 84, p. 237–292.</ref> (equivalent to the jet-plume deposits, jet-plume-complex deposits, and delta lobes of Wellner et al.<ref name=Wllnr2005>Wellner, R., R. Beaubouef, J. C. Van Wagoner, H. H. Roberts, and T. Sun, 2005, Jet-plume depositional bodies—The primary building blocks of Wax Lake delta: Transactions of the Gulf Coast Association of Geological Societies, v. 55, p. 867–909.</ref>). Sediment-body geometry is modified by the action of waves and tides, which respectively tend to result in shoreline-parallel and shoreline-perpendicular sediment transport that suppresses branching and switching of distributary channels (e.g., Galloway;<ref name=Glwy /> Willis;<ref >Willis, B. J., 2005, Deposits of tide-influenced river deltas, in L. Giosan, and J. P. Bhattacharya, eds., River deltas—Concepts, models, and examples: SEPM Special Publication 83, p. 87–129.</ref> Bhattacharya;<ref name=Bhttchry2006 /> Plink-Björklund<ref>Plink-Björklund, P., 2012, Effects of tides on deltaic deposition: Causes and responses: Sedimentary Geology, v. 279, p. 107–133, doi: 10.1016/j.sedgeo.2011.07.006.</ref>). Clinoforms exist as a preserved record of sediment-body morphologies at each of these hierarchical lengthscales (e.g., Gani and Bhattacharya<ref name=GB07>Gani, M. R., and J. P. Bhattacharya, 2007, Basic building blocks and process variability of a Cretaceous delta: Internal facies architecture reveals a more dynamic interaction of river, wave, and tidal processes than is indicated by external shape: Journal of Sedimentary Research, v. 77, no. 4, p. 284–302, doi: 10.2110/jsr.2007.023.</ref>) but are most commonly described at the scale of delta lobes in outcrop and high-resolution, shallow seismic data. For example, in Pleistocene fluvial-dominated delta deposits imaged in shallow-seismic data, Roberts et al.<ref name=Rbrts2004>Roberts, H. H., R. H. Fillon, B. Kohl, J. M. Robalin, and J. C. Sydow, 2004, Depositional architecture of the Lagniappe delta; sediment characteristics, timing of depositional events, and temporal relationship with adjacent shelf-edge deltas, in J. B. Anderson, and R. H. Fillon, eds., Late Quaternary stratigraphic evolution of the northern Gulf of Mexico margin: Tulsa, Oklahoma, SEPM Special Publication 79, p. 143–188.</ref> comment that “each clinoform set represents rather continuous deposition from a distributary or related set of distributaries, resulting in the formation of a delta lobe.” Shale drapes and cemented concretionary layers occur along depositional surfaces at each hierarchical level but generally have greater continuity and extent at larger lengthscales of the hierarchy (e.g., Gani and Bhattacharya;<ref name=GB07 /> Lee et al.;<ref>Lee, K., M. D. Gani, G. A. McMechan, J. P. Bhattacharya, S. Nyman, and X. Zeng, 2007, [http://archives.datapages.com/data/bulletns/2007/02feb/BLTN05114/BLTN05114.HTM Three-dimensional facies architecture and three-dimensional calcite concretion distributions in a tide-influenced delta front, Wall Creek Member, Frontier Formation, Wyoming]: AAPG Bulletin, v. 91, no. 2, p. 191–214, doi: 10.1306/08310605114.</ref> Ahmed et al.<ref name=Ahmd2014>Ahmed, S., J. P. Bhattacharya, D. Garza, and L. Giosan, 2014, Facies architecture and stratigraphic evolution of a river-dominated delta front, Turonian Ferron Sandstone, Utah, USA: Journal of Sedimentary Research, v. 84, no. 2, p. 97–121, doi: 10.2110/jsr.2014.6.</ref>). Thus, delta lobes tend to be overlain across flooding surfaces by prodelta shales and distal-delta-front heteroliths, which may cause them to behave as distinct reservoir zones that can be correlated between wells, whereas clinoforms are associated with heterogeneity between wells and within reservoir zones (e.g., Ainsworth et al.,;<ref name=Answrth1999 /> Hampson et al.<ref name=Hmpsn2008 />).

Clinoforms occur at a wide range of spatial scales, from large, basinward-dipping surfaces at the shelf-slope margin, to smaller surfaces associated with progradation of deltaic and shoreface systems across the shelf (e.g., Helland-Hansen and Hampson<ref name=HHH>Helland-Hansen, W., and G. J. Hampson, 2009, Trajectory analysis: Concepts and applications: Basin Research, v. 21, no. 5, p. 454–483, doi: 10.1111/j.1365-2117.2009.00425.x.</ref>). This study focuses on developing a surface-based approach to represent clinoforms at any lengthscale in reservoir models, with emphasis on clinoforms produced by the progradation of deltaic, barrier-island, and strandplain shorelines, which are typically up to a few tens of meters in height. The 3-D geometry and spatial arrangement of shoreline-scale clinoforms reflect in large part the process regime under which they were deposited (e.g., Galloway<ref name=Glwy>Galloway, W. E., 1975, Process framework for describing the morphological and stratigraphic evolution of deltaic depositional systems, in M. L. Broussard, ed., Deltas, models for exploration: Houston, Texas, Houston Geological Society, p. 87–98.</ref>). Fluvial-dominated deltas exhibit a hierarchy of point-sourced, teardrop-shaped sediment bodies that are fed via a downstream branching network of distributary channels. From small to large lengthscales, this hierarchy consists of mouth bars, mouth-bar assemblages, and delta lobes<ref name=Bhttchry2006>Bhattacharya, J. P., 2006, Deltas, inH. W. Posamentier, and R. Walker, eds., Facies models revisited: SEPM Special Publication 84, p. 237–292.</ref> (equivalent to the jet-plume deposits, jet-plume-complex deposits, and delta lobes of Wellner et al.<ref name=Wllnr2005>Wellner, R., R. Beaubouef, J. C. Van Wagoner, H. H. Roberts, and T. Sun, 2005, Jet-plume depositional bodies—The primary building blocks of Wax Lake delta: Transactions of the Gulf Coast Association of Geological Societies, v. 55, p. 867–909.</ref>). Sediment-body geometry is modified by the action of waves and tides, which respectively tend to result in shoreline-parallel and shoreline-perpendicular sediment transport that suppresses branching and switching of distributary channels (e.g., Galloway;<ref name=Glwy /> Willis;<ref >Willis, B. J., 2005, Deposits of tide-influenced river deltas, in L. Giosan, and J. P. Bhattacharya, eds., River deltas—Concepts, models, and examples: SEPM Special Publication 83, p. 87–129.</ref> Bhattacharya;<ref name=Bhttchry2006 /> Plink-Björklund<ref>Plink-Björklund, P., 2012, Effects of tides on deltaic deposition: Causes and responses: Sedimentary Geology, v. 279, p. 107–133, doi: 10.1016/j.sedgeo.2011.07.006.</ref>). Clinoforms exist as a preserved record of sediment-body morphologies at each of these hierarchical lengthscales (e.g., Gani and Bhattacharya<ref name=GB07>Gani, M. R., and J. P. Bhattacharya, 2007, Basic building blocks and process variability of a Cretaceous delta: Internal facies architecture reveals a more dynamic interaction of river, wave, and tidal processes than is indicated by external shape: Journal of Sedimentary Research, v. 77, no. 4, p. 284–302, doi: 10.2110/jsr.2007.023.</ref>) but are most commonly described at the scale of delta lobes in outcrop and high-resolution, shallow seismic data. For example, in Pleistocene fluvial-dominated delta deposits imaged in shallow-seismic data, Roberts et al.<ref name=Rbrts2004>Roberts, H. H., R. H. Fillon, B. Kohl, J. M. Robalin, and J. C. Sydow, 2004, Depositional architecture of the Lagniappe delta; sediment characteristics, timing of depositional events, and temporal relationship with adjacent shelf-edge deltas, in J. B. Anderson, and R. H. Fillon, eds., Late Quaternary stratigraphic evolution of the northern Gulf of Mexico margin: Tulsa, Oklahoma, SEPM Special Publication 79, p. 143–188.</ref> comment that “each clinoform set represents rather continuous deposition from a distributary or related set of distributaries, resulting in the formation of a delta lobe.” Shale drapes and cemented concretionary layers occur along depositional surfaces at each hierarchical level but generally have greater continuity and extent at larger lengthscales of the hierarchy (e.g., Gani and Bhattacharya;<ref name=GB07 /> Lee et al.;<ref>Lee, K., M. D. Gani, G. A. McMechan, J. P. Bhattacharya, S. Nyman, and X. Zeng, 2007, [http://archives.datapages.com/data/bulletns/2007/02feb/BLTN05114/BLTN05114.HTM Three-dimensional facies architecture and three-dimensional calcite concretion distributions in a tide-influenced delta front, Wall Creek Member, Frontier Formation, Wyoming]: AAPG Bulletin, v. 91, no. 2, p. 191–214, doi: 10.1306/08310605114.</ref> Ahmed et al.<ref name=Ahmd2014>Ahmed, S., J. P. Bhattacharya, D. Garza, and L. Giosan, 2014, Facies architecture and stratigraphic evolution of a river-dominated delta front, Turonian Ferron Sandstone, Utah, USA: Journal of Sedimentary Research, v. 84, no. 2, p. 97–121, doi: 10.2110/jsr.2014.6.</ref>). Thus, delta lobes tend to be overlain across flooding surfaces by prodelta shales and distal-delta-front heteroliths, which may cause them to behave as distinct reservoir zones that can be correlated between wells, whereas clinoforms are associated with heterogeneity between wells and within reservoir zones (e.g., Ainsworth et al.,;<ref name=Answrth1999 /> Hampson et al.<ref name=Hmpsn2008 />).

The clinoform-modeling algorithm developed here is simple to use, requiring specification of only a few input parameters: (1) the upper and lower surfaces that define the rock volume within which the clinoforms are to be modeled; (2) the plan-view geometry of clinoforms; (3) clinoform geometry in depositional-dip-oriented cross section; and (4) spacing and progradation direction of the clinoforms. The user can also use a stochastic component of the clinoform-modeling algorithm if there are uncertainties in the parameter values to be used.

The clinoform-modeling algorithm developed here is simple to use, requiring specification of only a few input parameters: (1) the upper and lower surfaces that define the rock volume within which the clinoforms are to be modeled; (2) the plan-view geometry of clinoforms; (3) clinoform geometry in depositional-dip-oriented [[cross section]]; and (4) spacing and progradation direction of the clinoforms. The user can also use a stochastic component of the clinoform-modeling algorithm if there are uncertainties in the parameter values to be used.

===Bounding Surfaces That Define Rock Volume===

===Bounding Surfaces That Define Rock Volume===

===Cross-Sectional Clinoform Geometry===

===Cross-Sectional Clinoform Geometry===

The shape and dip angle of a deltaic or shoreface clinoform in cross section is a function of modal grain size, proportion of mud, and the depositional process regime at the shoreline. In sandy, fluvial-dominated deltas, clinoforms have simple concave-upward geometries and steep dip angles (up to 15°)<ref name=GB05 /> (e.g., [[:File:BLTN13190fig1.jpg|Figure 1]]). Similar geometries have been documented in sandy, tide-influenced deltas (dip angles up to 5°–15°).<ref name=Wllsetal1999>Willis, B. J., J. P. Bhattacharya, S. L. Gabel, and C. D. White, 1999, Architecture of a tide-influenced river delta in the Frontier Formation of central Wyoming, USA: Sedimentology, v. 46, no. 4, p. 667–688, doi: 10.1046/j.1365-3091.1999.00239.x.</ref> Concave-upward clinoform geometry is also typical of sandy, wave-dominated deltas and strandplains, although the clinoforms have smaller dip angles (typically up to 1°–2°).<ref>Hampson, G. J., and J. E. A. Storms, 2003, Geomorphological and sequence stratigraphic variability in wave-dominated shoreface-shelf parasequences: Sedimentology, v. 50, no. 4, p. 667–701, doi: 10.1046/j.1365-3091.2003.00570.x.</ref><ref name=GB05 /> Clinoforms are consistently inclined paleobasinward down depositional dip; and, along depositional strike, they exhibit bidirectional, concave-upward dips if the delta-front was lobate in plan view (e.g., Willis et al.;<ref name=Wllsetal1999 /> Kolla et al.;<ref name=Kll>Kolla, V., P. Biondi, B. Long, and R. Fillon, 2000, Sequence stratigraphy and architecture of the late Pleistocene Lagniappe delta complex, northeast Gulf of Mexico, inD. Hunt, and R. L. Gawthorpe, eds., Sedimentary responses to forced regressions: Geological Society, London, Special Publication 172, p. 291–327.</ref> Roberts et al.<ref name=Rbrts2004 />) or appear horizontal if the shoreline was approximately linear (e.g., Hampson<ref name=Hmpsn2000 />). Clinoforms are usually truncated at their tops by a variety of channelized erosion surfaces formed during shoreline advance (e.g., distributary channels, incised valleys) and by channelized and/or planar transgressive erosion surfaces (tide and wave ravinement surfaces sense Swift<ref>Swift, D. J., 1968, Coastal erosion and transgressive stratigraphy: Journal of Geology, v. 76, no. 4, p. 444–456, doi: 10.1086/jg.1968.76.issue-4.</ref>) associated with shoreline retreat. Consequently, most sandy shoreline clinoforms lack a decrease in depositional dip (rollover) near their tops, although this geometry is ubiquitous in larger, shelf-slope margin clinoforms (e.g., Steckler et al.<ref name=Stcklr1999>Steckler, M. S., G. S. Mountain, K. G. Miller, and N. Christie-Blick, 1999, Reconstruction of tertiary progradation and clinoform development on the New Jersey passive margin by 2D backstripping: Marine Geology, v. 154, no. 1–4, p. 399–420, doi: 10.1016/S0025-3227(98)00126-1.</ref>) and in the outer, muddy portion of compound deltaic clinoforms with a broad subaqueous topset that lies seaward of the shoreline (e.g., Pirmez et al.<ref>Pirmez, C., L. F. Pratson, and M. S. Steckler, 1998, Clinoform development by advection-diffusion of suspended sediment; modeling and comparison to natural systems: Journal of Geophysical Research B: Solid Earth and Planets, v. 103, p. 24,141–24,157, doi: 10.1029/98JB01516.</ref>).

The shape and dip angle of a deltaic or shoreface clinoform in [[cross section]] is a function of modal grain size, proportion of mud, and the depositional process regime at the shoreline. In sandy, fluvial-dominated deltas, clinoforms have simple concave-upward geometries and steep dip angles (up to 15°)<ref name=GB05 /> (e.g., [[:File:BLTN13190fig1.jpg|Figure 1]]). Similar geometries have been documented in sandy, tide-influenced deltas (dip angles up to 5°–15°).<ref name=Wllsetal1999>Willis, B. J., J. P. Bhattacharya, S. L. Gabel, and C. D. White, 1999, Architecture of a tide-influenced river delta in the Frontier Formation of central Wyoming, USA: Sedimentology, v. 46, no. 4, p. 667–688, doi: 10.1046/j.1365-3091.1999.00239.x.</ref> Concave-upward clinoform geometry is also typical of sandy, wave-dominated deltas and strandplains, although the clinoforms have smaller dip angles (typically up to 1°–2°).<ref>Hampson, G. J., and J. E. A. Storms, 2003, Geomorphological and sequence stratigraphic variability in wave-dominated shoreface-shelf parasequences: Sedimentology, v. 50, no. 4, p. 667–701, doi: 10.1046/j.1365-3091.2003.00570.x.</ref><ref name=GB05 /> Clinoforms are consistently inclined paleobasinward down depositional dip; and, along depositional strike, they exhibit bidirectional, concave-upward dips if the delta-front was lobate in plan view (e.g., Willis et al.;<ref name=Wllsetal1999 /> Kolla et al.;<ref name=Kll>Kolla, V., P. Biondi, B. Long, and R. Fillon, 2000, Sequence stratigraphy and architecture of the late Pleistocene Lagniappe delta complex, northeast Gulf of Mexico, inD. Hunt, and R. L. Gawthorpe, eds., Sedimentary responses to forced regressions: Geological Society, London, Special Publication 172, p. 291–327.</ref> Roberts et al.<ref name=Rbrts2004 />) or appear horizontal if the shoreline was approximately linear (e.g., Hampson<ref name=Hmpsn2000 />). Clinoforms are usually truncated at their tops by a variety of channelized erosion surfaces formed during shoreline advance (e.g., distributary channels, incised valleys) and by channelized and/or planar transgressive erosion surfaces (tide and wave ravinement surfaces sense Swift<ref>Swift, D. J., 1968, Coastal erosion and transgressive stratigraphy: Journal of Geology, v. 76, no. 4, p. 444–456, doi: 10.1086/jg.1968.76.issue-4.</ref>) associated with shoreline retreat. Consequently, most sandy shoreline clinoforms lack a decrease in depositional dip (rollover) near their tops, although this geometry is ubiquitous in larger, shelf-slope margin clinoforms (e.g., Steckler et al.<ref name=Stcklr1999>Steckler, M. S., G. S. Mountain, K. G. Miller, and N. Christie-Blick, 1999, Reconstruction of tertiary progradation and clinoform development on the New Jersey passive margin by 2D backstripping: Marine Geology, v. 154, no. 1–4, p. 399–420, doi: 10.1016/S0025-3227(98)00126-1.</ref>) and in the outer, muddy portion of compound deltaic clinoforms with a broad subaqueous topset that lies seaward of the shoreline (e.g., Pirmez et al.<ref>Pirmez, C., L. F. Pratson, and M. S. Steckler, 1998, Clinoform development by advection-diffusion of suspended sediment; modeling and comparison to natural systems: Journal of Geophysical Research B: Solid Earth and Planets, v. 103, p. 24,141–24,157, doi: 10.1029/98JB01516.</ref>).

Here, a geometric approach is used to represent the depositional dip cross-section shape of a clinoform with a dimensionless shape function, ''s(r_c)'' ([[:File:BLTN13190fig2.jpg|Figure 2E]]), such as a power law for concave-upward, sandy, shoreline clinoforms:  

Here, a geometric approach is used to represent the depositional dip cross-section shape of a clinoform with a dimensionless shape function, ''s(r_c)'' ([[:File:BLTN13190fig2.jpg|Figure 2E]]), such as a power law for concave-upward, sandy, shoreline clinoforms:  

Each of the input parameters described for the clinoform-modeling algorithm can be applied deterministically; however, many can also be applied stochastically (Table 1). If a reservoir model is created using an outcrop data set, it may be appropriate for the user to specify the parameter values for each clinoform. If a subsurface reservoir model is being created in which the parameter values are uncertain, the user can constrain a continuous probability distribution, such as a normal distribution, to assign values to each parameter. The user specifies the mean, standard deviation, and maximum and minimum values for the distribution. Values are then drawn at random from the distribution to assign values to the parameters.

Each of the input parameters described for the clinoform-modeling algorithm can be applied deterministically; however, many can also be applied stochastically (Table 1). If a reservoir model is created using an outcrop data set, it may be appropriate for the user to specify the parameter values for each clinoform. If a subsurface reservoir model is being created in which the parameter values are uncertain, the user can constrain a continuous probability distribution, such as a normal distribution, to assign values to each parameter. The user specifies the mean, standard deviation, and maximum and minimum values for the distribution. Values are then drawn at random from the distribution to assign values to the parameters.

Because many of the input parameters can be defined stochastically, one of the consequences of this aspect of the clinoform-modeling algorithm is that it is possible to generate complex geometries, such as cases in which clinoforms are observed to onlap against older clinoforms in the same parasequence. A combination of three factors is postulated to cause subtle changes in clinoform geometry and position, which combine to produce onlap in depositional-dip-oriented cross sections: (1) in fluvial-dominated deltas, distributary mouth bars and bar complexes have complex 3-D geometries that can shift along depositional strike as well as down depositional dip (e.g., Olariu et al.;<ref>Olariu, C., J. P. Bhattacharya, X. Xu, C. L. Aiken, X. Zeng, and G. A. McMechan, 2005, Integrated study of ancient delta-front deposits, using outcrop ground-penetrating radar, and three-dimensional photorealistic data: Cretaceous Panther Tongue Sandstone, Utah, U.S.A., inL. Giosan, and J. P. Bhattacharya, eds., River deltas—Concepts, models and examples: Tulsa, Oklahoma, SEPM Special Publication 83, p. 155–177.</ref> Wellner et al.<ref name=Wllnr2005 />); (2) riverine sediment supply to delta-front clinoforms exhibits temporal and spatial variability that is related, at least in part, to downstream branching and switching of distributary channels as deltas advance (e.g., Wellner et al.;<ref name=Wllnr2005 /> Ahmed et al.<ref name=Ahmd2014 />); and (3) clinoform geometries are locally modified by basinal processes such as waves and tides (e.g., Gani and Bhattacharya<ref name=GB07 />).

Because many of the input parameters can be defined stochastically, one of the consequences of this aspect of the clinoform-modeling algorithm is that it is possible to generate complex geometries, such as cases in which clinoforms are observed to onlap against older clinoforms in the same parasequence. A combination of three factors is postulated to cause subtle changes in clinoform geometry and position, which combine to produce onlap in depositional-dip-oriented [[cross section]]s: (1) in fluvial-dominated deltas, distributary mouth bars and bar complexes have complex 3-D geometries that can shift along depositional strike as well as down depositional dip (e.g., Olariu et al.;<ref>Olariu, C., J. P. Bhattacharya, X. Xu, C. L. Aiken, X. Zeng, and G. A. McMechan, 2005, Integrated study of ancient delta-front deposits, using outcrop ground-penetrating radar, and three-dimensional photorealistic data: Cretaceous Panther Tongue Sandstone, Utah, U.S.A., inL. Giosan, and J. P. Bhattacharya, eds., River deltas—Concepts, models and examples: Tulsa, Oklahoma, SEPM Special Publication 83, p. 155–177.</ref> Wellner et al.<ref name=Wllnr2005 />); (2) riverine sediment supply to delta-front clinoforms exhibits temporal and spatial variability that is related, at least in part, to downstream branching and switching of distributary channels as deltas advance (e.g., Wellner et al.;<ref name=Wllnr2005 /> Ahmed et al.<ref name=Ahmd2014 />); and (3) clinoform geometries are locally modified by basinal processes such as waves and tides (e.g., Gani and Bhattacharya<ref name=GB07 />).

To produce onlap and other subtle geometric features between successive clinoforms, the user can use the stochastic component of the clinoform-modeling algorithm to generate small variations in the parameter values of either or all of the following: progradation direction, ''θ''; clinoform spacing, ''S''; and clinoform length, ''L''. If the parameters that define a clinoform cause it to be present below an earlier surface, it is truncated by the earlier surface to produce onlap. Application of the algorithm to (1) a rich, outcrop data set and (2) a sparse, subsurface data set is described in the examples in the following two sections.

To produce onlap and other subtle geometric features between successive clinoforms, the user can use the stochastic component of the clinoform-modeling algorithm to generate small variations in the parameter values of either or all of the following: progradation direction, ''θ''; clinoform spacing, ''S''; and clinoform length, ''L''. If the parameters that define a clinoform cause it to be present below an earlier surface, it is truncated by the earlier surface to produce onlap. Application of the algorithm to (1) a rich, outcrop data set and (2) a sparse, subsurface data set is described in the examples in the following two sections.

</gallery>

</gallery>

The clinoforms incorporated into the Troll sector model show similar geometries and spacing to those that are seismically resolved in the Sognefjord Formation.<ref name=Dryr2005 /><ref name=Ptrno /> The clinoforms are linear in plan view over the small (750 m [2461 ft]) depositional-strike extent of the model ([[:File:BLTN13190fig14.jpg|Figure 14B]]), consistent with the interpreted plan-view geometries of wave-dominated shoreface systems ([[:File:BLTN13190fig3.jpg|Figure 3A]]),<ref name=Hwll2008a /> consistently prograde west-northwestward (θ = 320°), as established through 3-D seismic data,<ref name=Dryr2005 /><ref name=Ptrno /> and have the concave-upward geometry observed in seismic dip sections through the Sognefjord Formation<ref name=Dryr2005 /><ref name=Ptrno /> ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]). In depositional strike cross section, the algorithm produces near-horizontal clinoform geometries, consistent with seismically resolved clinoforms<ref name=Dryr2005 /><ref name=Ptrno /> ([[:File:BLTN13190fig15.jpg|Figure 15C]]). The stochastic component of the clinoform-modeling algorithm distributes clinoforms with cross-sectional geometries and spacings ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]) that are consistent with outcrop studies of wave-dominated deltas<ref name=Hmpsn2000>Hampson, G. J., 2000, Discontinuity surfaces, clinoforms and facies architecture in a wave-dominated, shoreface-shelf parasequence: Journal of Sedimentary Research, v. 70, no. 2, p. 325–340, doi: 10.1306/2DC40914-0E47-11D7-8643000102C1865D.</ref><ref name=Sch09 /> ([[:File:BLTN13190fig13.jpg|Figure 13]]) and honor the sparse subsurface data. In contrast to the Ferron Sandstone Member example, the Troll West sector model does not contain subtle clinoform geometries, such as onlap and downlap of younger clinoforms on to older clinoforms ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]). Such features are below the resolution of the seismic data used to extract the parameters that were used in the algorithm. The clinoforms are also faulted in the same way as the parasequence-bounding flooding surfaces (cf. [[:File:BLTN13190fig2.jpg|Figures 2A]], [[:File:BLTN13190fig15.jpg|15C]]).

The clinoforms incorporated into the Troll sector model show similar geometries and spacing to those that are seismically resolved in the Sognefjord Formation.<ref name=Dryr2005 /><ref name=Ptrno /> The clinoforms are linear in plan view over the small (750 m [2461 ft]) depositional-strike extent of the model ([[:File:BLTN13190fig14.jpg|Figure 14B]]), consistent with the interpreted plan-view geometries of wave-dominated shoreface systems ([[:File:BLTN13190fig3.jpg|Figure 3A]]),<ref name=Hwll2008a /> consistently prograde west-northwestward (θ = 320°), as established through 3-D seismic data,<ref name=Dryr2005 /><ref name=Ptrno /> and have the concave-upward geometry observed in seismic dip sections through the Sognefjord Formation<ref name=Dryr2005 /><ref name=Ptrno /> ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]). In depositional strike [[cross section]], the algorithm produces near-horizontal clinoform geometries, consistent with seismically resolved clinoforms<ref name=Dryr2005 /><ref name=Ptrno /> ([[:File:BLTN13190fig15.jpg|Figure 15C]]). The stochastic component of the clinoform-modeling algorithm distributes clinoforms with cross-sectional geometries and spacings ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]) that are consistent with outcrop studies of wave-dominated deltas<ref name=Hmpsn2000>Hampson, G. J., 2000, Discontinuity surfaces, clinoforms and facies architecture in a wave-dominated, shoreface-shelf parasequence: Journal of Sedimentary Research, v. 70, no. 2, p. 325–340, doi: 10.1306/2DC40914-0E47-11D7-8643000102C1865D.</ref><ref name=Sch09 /> ([[:File:BLTN13190fig13.jpg|Figure 13]]) and honor the sparse subsurface data. In contrast to the Ferron Sandstone Member example, the Troll West sector model does not contain subtle clinoform geometries, such as onlap and downlap of younger clinoforms on to older clinoforms ([[:File:BLTN13190fig14.jpg|Figures 14A]], [[:File:BLTN13190fig15.jpg|15B]]). Such features are below the resolution of the seismic data used to extract the parameters that were used in the algorithm. The clinoforms are also faulted in the same way as the parasequence-bounding flooding surfaces (cf. [[:File:BLTN13190fig2.jpg|Figures 2A]], [[:File:BLTN13190fig15.jpg|15C]]).

===Production Strategy===

===Production Strategy===