Changes

[[File:BLTN13190fig2.jpg|thumb|300px|{{figure number|2}}Examples of clinoforms produced by the clinoform-modeling algorithm conditioned to different bounding surfaces and clinoform geometries. (A) Bounding surfaces represent postdepositional compaction and folding of the original (depositional) geometries of the clinoform and the top and base bounding surfaces. (B) Bounding surfaces represent a clinoform within a volume truncated at its top, for example, by a channel ([[:File:BLTN13190fig1.jpg|Figure 1]]). (C) Bounding surfaces represent a clinoform downlapping onto irregular sea-floor topography. (D) Height function, ''h(r_c)'' (equation 1; see Table 1 for nomenclature). (E) Shape function, ''s(r_c)'' (equation 7; Table 1), demonstrating that increasing the exponent, ''P'', increases the dip angle of clinoforms.]]

[[File:BLTN13190fig2.jpg|thumb|300px|{{figure number|2}}Examples of clinoforms produced by the clinoform-modeling algorithm conditioned to different bounding surfaces and clinoform geometries. (A) Bounding surfaces represent postdepositional compaction and folding of the original (depositional) geometries of the clinoform and the top and base bounding surfaces. (B) Bounding surfaces represent a clinoform within a volume truncated at its top, for example, by a channel ([[:File:BLTN13190fig1.jpg|Figure 1]]). (C) Bounding surfaces represent a clinoform downlapping onto irregular sea-floor topography. (D) Height function, ''h(r_c)'' (equation 1; see Table 1 for nomenclature). (E) Shape function, ''s(r_c)'' (equation 7; Table 1), demonstrating that increasing the exponent, ''P'', increases the dip angle of clinoforms.]]

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, inJ. 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.

==Example 1: Ferron sandstone reservoir analog==

==Example 1: Ferron sandstone reservoir analog==

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BLTN13190fig5.jpg|{{figure number|5}}(A) Paleogeographic reconstruction of the Late Cretaceous Last Chance and Vernal delta systems of the Ferron Sandstone Member of the Mancos Shale in present-day Utah (after Cotter, 1976; used with permission of Brigham Young University). The location of the Deveugle et al.<ref name=Dvgl2011 /> model ([[:File:BLTN13190fig5.jpg|Figure 5D]]) and a regional cross section ([[:File:BLTN13190fig5.jpg|Figure 5B]]) are highlighted. (B) Schematic regional cross section through the Last Chance delta system of the Ferron Sandstone Member and its eight-component shallow-marine tongues (termed “pararasequence sets,” using the nomenclature of Deveugle et al.,<ref name=Dvgl2011 /> and numbered PSS1 to PSS8), from southwest (paleolandward) to northeast (paleoseaward) (after Anderson and Ryer, 2004; used with permission of AAPG). (C) Detailed cross section through the lowermost shallow-marine tongues (termed “parasequences,” using the nomenclature of Deveugle et al.,<ref name=Dvgl2011 /> and forming PSS1 in [[:File:BLTN13190fig5.jpg|Figure 5B]]) and associated coastal-plain strata (after Garrison and Van den Bergh, 2004; used with permission of AAPG). The tongue is subdivided into constituent parasequences (after Deveugle et al.<ref name=Dvgl2011 />). Parasequence 1.6 is modeled in this study. (D) Distribution of facies-association belts at the top of parasequence 1.6, in the Deveugle et al.<ref name=Dvgl2011 /> model area in the Ivie Creek amphitheater. The area of the model constructed in this study (Figures 7–10) lies within the dashed lines.

BLTN13190fig5.jpg|{{figure number|5}}(A) Paleogeographic reconstruction of the Late Cretaceous Last Chance and Vernal delta systems of the Ferron Sandstone Member of the Mancos Shale in present-day Utah (after Cotter, 1976; used with permission of Brigham Young University). The location of the Deveugle et al.<ref name=Dvgl2011 /> model ([[:File:BLTN13190fig5.jpg|Figure 5D]]) and a regional cross section ([[:File:BLTN13190fig5.jpg|Figure 5B]]) are highlighted. (B) Schematic regional cross section through the Last Chance delta system of the Ferron Sandstone Member and its eight-component shallow-marine tongues (termed “pararasequence sets,” using the nomenclature of Deveugle et al.,<ref name=Dvgl2011 /> and numbered PSS1 to PSS8), from southwest (paleolandward) to northeast (paleoseaward) (after Anderson and Ryer;<ref name=AndrsnRyr2004>Anderson, P. B., and T. A. Ryer, 2004, [http://archives.datapages.com/data/specpubs/study50/sg50ch08/sg50ch08.htm Regional stratigraphy of the Ferron Sandstone], in T. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modeling: The Ferron Sandstone of Utah: [http://store.aapg.org/detail.aspx?id=655 AAPG Studies in Geology 50], p. 211–224.</ref> used with permission of AAPG). (C) Detailed cross section through the lowermost shallow-marine tongues (termed “parasequences,” using the nomenclature of Deveugle et al.,<ref name=Dvgl2011 /> and forming PSS1 in [[:File:BLTN13190fig5.jpg|Figure 5B]]) and associated coastal-plain strata (after Garrison and Van den Bergh;<ref name=GvdB2004>Garrison, J. R., and T. C. V. Van den Bergh, 2004, [http://archives.datapages.com/data/specpubs/study50/sg50ch06/sg50ch06.htm High resolution depositional sequence stratigraphy of the Upper Ferron Sandstone Last Chance Delta: An application of coal-zone stratigraphy], in T. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modelling: The Ferron Sandstone of Utah: [http://store.aapg.org/detail.aspx?id=655 AAPG Studies in Geology 50], p. 125–192.</ref> used with permission of AAPG). The tongue is subdivided into constituent parasequences (after Deveugle et al.<ref name=Dvgl2011 />). Parasequence 1.6 is modeled in this study. (D) Distribution of facies-association belts at the top of parasequence 1.6, in the Deveugle et al.<ref name=Dvgl2011 /> model area in the Ivie Creek amphitheater. The area of the model constructed in this study ([[:File:BLTN13190fig7.jpg|Figures 7]], [[:File:BLTN13190fig8.jpg|8]], [[:File:BLTN13190fig9.jpg|9]] & [[:File:BLTN13190fig10.jpg|10]]) lies within the dashed lines.

BLTN13190fig6.jpg|{{figure number|6}}(A) Interpreted line drawing of clinoforms in parasequence 1.6 at the Junction Point section of Ivie Creek amphitheater ([[:File:BLTN13190fig5.jpg|Figure 5D]]) (modified after Forster et al.<ref name=Frstr2004 />). Each clinoform bounds a mouth bar and equivalent delta-front deposits. Data from 104 clinoforms were collected to condition the clinoform-modeling algorithm. Frequency distributions of values measured from outcrop data for (B) clinoform length ([[:File:BLTN13190fig4.jpg|Figure 4D]]), and (C) clinoform spacing ([[:File:BLTN13190fig4.jpg|Figure 4D]]), which are used as input parameters in the clinoform-modeling algorithm (Table 2).

BLTN13190fig6.jpg|{{figure number|6}}(A) Interpreted line drawing of clinoforms in parasequence 1.6 at the Junction Point section of Ivie Creek amphitheater ([[:File:BLTN13190fig5.jpg|Figure 5D]]) (modified after Forster et al.<ref name=Frstr2004 />). Each clinoform bounds a mouth bar and equivalent delta-front deposits. Data from 104 clinoforms were collected to condition the clinoform-modeling algorithm. Frequency distributions of values measured from outcrop data for (B) clinoform length ([[:File:BLTN13190fig4.jpg|Figure 4D]]), and (C) clinoform spacing ([[:File:BLTN13190fig4.jpg|Figure 4D]]), which are used as input parameters in the clinoform-modeling algorithm (Table 2).

</gallery>

</gallery>

Construction and fluid-flow simulation of models based on outcrop analogs is an established method for investigating geologic controls on subsurface reservoir performance (e.g., Ciammetti et al., 1995; White and Barton, 1999; White et al., 2004; Jackson et al.;<ref name=Jckson2009 /> Sech et al.;<ref name=Sch09 /> Enge and Howell<ref name=EH2010 />). Here, the clinoform-modeling algorithm is used to build a reservoir model utilizing a high-resolution outcrop data set from the Ferron Sandstone Member, Utah, at a scale that is comparable to the interwell spacing (750 × 3000 m [2461 × 9843 ft] areally) in a typical hydrocarbon reservoir and captures several tens of clinoforms and their associated heterogeneities. Previously, Forster et al. <ref name=Frstr2004 /> constructed 2-D flow-simulation models of the same outcrop analog via data-intensive, deterministic mapping of clinoforms and facies boundaries in cliff-face exposures. In contrast, our aim is to verify that the clinoform-modeling algorithm can produce realistic 3-D stratigraphic architectures that mimic rich outcrop data sets when conditioned to sparse input data that are typical in the subsurface. The scale of the model fills the gap between detailed but sparse 2-D core and well-log data and low-resolution but extensive 3-D seismic data.

Construction and fluid-flow simulation of models based on outcrop analogs is an established method for investigating geologic controls on subsurface reservoir performance (e.g., Ciammetti et al., 1995; White and Barton, 1999; White et al., 2004; Jackson et al.;<ref name=Jckson2009 /> Sech et al.;<ref name=Sch09 /> Enge and Howell<ref name=EH2010 />). Here, the clinoform-modeling algorithm is used to build a reservoir model utilizing a high-resolution outcrop data set from the Ferron Sandstone Member, Utah, at a scale that is comparable to the interwell spacing (750 × 3000 m [2461 × 9843 ft] areally) in a typical hydrocarbon reservoir and captures several tens of clinoforms and their associated heterogeneities. Previously, Forster et al. <ref name=Frstr2004 /> constructed 2-D flow-simulation models of the same outcrop analog via data-intensive, deterministic mapping of clinoforms and facies boundaries in cliff-face exposures. In contrast, our aim is to verify that the clinoform-modeling algorithm can produce realistic 3-D stratigraphic architectures that mimic rich outcrop data sets when conditioned to sparse input data that are typical in the subsurface. The scale of the model fills the gap between detailed but sparse 2-D core and well-log data and low-resolution but extensive 3-D seismic data.

The Ferron Sandstone Member of the Mancos Shale is located in east-central Utah. The unit was deposited during the Late Cretaceous (Turonian–Coniacian) on the western margin of the Western Interior Seaway and, in the study area, records the progradation of the Last Chance delta system from southwest (paleolandward) to northeast (paleoseaward) (Cotter, 1976) ([[:File:BLTN13190fig5.jpg|Figure 5A]]). These deltaic deposits form a basinward-thinning wedge that passes eastward into the offshore deposits of the Mancos Shale. The wedge contains either seven (Ryer, 1991; Gardner, 1993; Barton et al., 2004) or eight sandstone tongues (Anderson and Ryer, 2004; Garrison and Van den Bergh, 2004), such that one tongue is equivalent to a parasequence set of Deveugle et al.<ref name=Dvgl2011 /> ([[:File:BLTN13190fig5.jpg|Figure 5B]]). A single delta-lobe deposit within the lowermost sandstone tongue is the focus of the study (bedset Kf-1-Iv[a] of Anderson et al., 2004; parasequence 1h of Garrison and Van den Bergh, 2004; parasequence 1.6 of Deveugle et al.<ref name=Dvgl2011 />) ([[:File:BLTN13190fig5.jpg|Figure 5C, D]]). The delta-lobe deposit is fluvial dominated with low-to-moderate wave influence (Gardner, 1993; Garrison and Van den Bergh, 2004; Ryer and Anderson, 2004) and contains numerous, well-documented clinoforms in the exposures of the Ivie Creek amphitheater (Anderson et al., 2002, 2003, 2004; <ref name=Frstr2004 /><ref name=EH2010 /> ([[:File:BLTN13190fig5.jpg|Figure 5D]]). Clinoform-related bedding geometries and facies distributions imply that clinoforms mapped by previous workers, and used as input data for the models presented below ([[:File:BLTN13190fig6.jpg|Figure 6A]], after Forster et al. <ref name=Frstr2004 />), bound clinothems equivalent to mouth bars (sensu Bhattacharya<ref name=Bhttchry2006 />). Subtle, apparently cyclic variations in clinoform spacing and dip angle probably define mouth-bar assemblages (sensu Bhattacharya;<ref name=Bhttchry2006 /> “bedsets” sensu Enge et al., 2010). Smaller-scale lithologic variation at the scale of individual beds occurs between the mapped clinoforms and records incremental growth of a mouth bar because of varying water and sediment discharge through the feeder distributary channel. Deveugle et al.<ref name=Dvgl2011 /> used a high-resolution outcrop data set to build a reservoir-scale (7200 × 3800 × 50 m [23622 × 12467 × 164 ft]), surface-based model of the lower two tongues (parasequence sets) of the Ferron Sandstone Member. Clinoforms were not represented in the delta-lobe deposits (cf. parasequences) of the Deveugle et al.<ref name=Dvgl2011 /> model, and their surface-based model is used here as the context in which the clinoform-modeling algorithm should be applied.

The Ferron Sandstone Member of the Mancos Shale is located in east-central Utah. The unit was deposited during the Late Cretaceous (Turonian–Coniacian) on the western margin of the Western Interior Seaway and, in the study area, records the progradation of the Last Chance delta system from southwest (paleolandward) to northeast (paleoseaward) (Cotter, 1976) ([[:File:BLTN13190fig5.jpg|Figure 5A]]). These deltaic deposits form a basinward-thinning wedge that passes eastward into the offshore deposits of the Mancos Shale. The wedge contains either seven (Ryer, 1991; Gardner, 1993; Barton et al., 2004) or eight sandstone tongues,<ref name=AndrsnRyr2004 /><ref name=GvdB2004 /> such that one tongue is equivalent to a parasequence set of Deveugle et al.<ref name=Dvgl2011 /> ([[:File:BLTN13190fig5.jpg|Figure 5B]]). A single delta-lobe deposit within the lowermost sandstone tongue is the focus of the study (bedset Kf-1-Iv[a] of Anderson et al., 2004; parasequence 1h of Garrison and Van den Bergh;<ref name=GvdB2004 /> parasequence 1.6 of Deveugle et al.<ref name=Dvgl2011 />) ([[:File:BLTN13190fig5.jpg|Figure 5C, D]]). The delta-lobe deposit is fluvial dominated with low-to-moderate wave influence (Gardner, 1993; <ref name=GvdB2004 /> Ryer and Anderson, 2004) and contains numerous, well-documented clinoforms in the exposures of the Ivie Creek amphitheater (Anderson et al., 2002, 2003, 2004; <ref name=Frstr2004 /><ref name=EH2010 /> ([[:File:BLTN13190fig5.jpg|Figure 5D]]). Clinoform-related bedding geometries and facies distributions imply that clinoforms mapped by previous workers, and used as input data for the models presented below ([[:File:BLTN13190fig6.jpg|Figure 6A]], after Forster et al. <ref name=Frstr2004 />), bound clinothems equivalent to mouth bars (sensu Bhattacharya<ref name=Bhttchry2006 />). Subtle, apparently cyclic variations in clinoform spacing and dip angle probably define mouth-bar assemblages (sensu Bhattacharya;<ref name=Bhttchry2006 /> “bedsets” sensu Enge et al., 2010). Smaller-scale lithologic variation at the scale of individual beds occurs between the mapped clinoforms and records incremental growth of a mouth bar because of varying water and sediment discharge through the feeder distributary channel. Deveugle et al.<ref name=Dvgl2011 /> used a high-resolution outcrop data set to build a reservoir-scale (7200 × 3800 × 50 m [23622 × 12467 × 164 ft]), surface-based model of the lower two tongues (parasequence sets) of the Ferron Sandstone Member. Clinoforms were not represented in the delta-lobe deposits (cf. parasequences) of the Deveugle et al.<ref name=Dvgl2011 /> model, and their surface-based model is used here as the context in which the clinoform-modeling algorithm should be applied.

===Model Construction===

===Model Construction===

# Anderson, P. B., T. C. Chidsey, Jr., T. A. Ryer, R. D. Adams, and K. McClure, 2004, Geological framework, facies paleogeography, and reservoir analogs of the Ferron Sandstone in the Ivie Creek area, east-central Utah, inT. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modeling: The Ferron Sandstone of Utah: AAPG Studies in Geology 50, p. 331–356.

# Anderson, P. B., T. C. Chidsey, Jr., T. A. Ryer, R. D. Adams, and K. McClure, 2004, Geological framework, facies paleogeography, and reservoir analogs of the Ferron Sandstone in the Ivie Creek area, east-central Utah, inT. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modeling: The Ferron Sandstone of Utah: AAPG Studies in Geology 50, p. 331–356.

# Anderson, P. B., K. McClure, T. C. Chidsey, Jr., T. A. Ryer, T. H. Morris, J. A. Dewey, Jr., and R. D. Adams, 2003, Interpreted regional photomosaics and cross sections, Cretaceous Ferron Sandstone, east-central Utah: Utah Geological Survey, Open File Report 412, CD-ROM.

# Anderson, P. B., K. McClure, T. C. Chidsey, Jr., T. A. Ryer, T. H. Morris, J. A. Dewey, Jr., and R. D. Adams, 2003, Interpreted regional photomosaics and cross sections, Cretaceous Ferron Sandstone, east-central Utah: Utah Geological Survey, Open File Report 412, CD-ROM.

# Anderson, P. B., and T. A. Ryer, 2004, Regional stratigraphy of the Ferron Sandstone, inT. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modeling: The Ferron Sandstone of Utah: AAPG Studies in Geology 50, p. 211–224.

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# Bakke, N. E., E. T. Ertresvåg, A. Næss, A. C. MacDonald, and L. M. Fält, 1996, Application of seismic data and sequence stratigraphy for constraining a stochastic model of calcite cementation: SPE Paper 35487, 13 p.

# Bakke, N. E., E. T. Ertresvåg, A. Næss, A. C. MacDonald, and L. M. Fält, 1996, Application of seismic data and sequence stratigraphy for constraining a stochastic model of calcite cementation: SPE Paper 35487, 13 p.

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# Gardner, M. H., 1993, Sequence stratigraphy and facies architecture of the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale, east-central Utah: Ph.D. dissertation, Colorado School of Mines, Golden, Colorado, 528 p.

# Gardner, M. H., 1993, Sequence stratigraphy and facies architecture of the Upper Cretaceous Ferron Sandstone Member of the Mancos Shale, east-central Utah: Ph.D. dissertation, Colorado School of Mines, Golden, Colorado, 528 p.

# Garrison, J. R., and T. C. V. Van den Bergh, 2004, High resolution depositional sequence stratigraphy of the Upper Ferron Sandstone Last Chance Delta: An application of coal-zone stratigraphy, inT. C. Chidsey, Jr., R. D. Adams, and T. H. Morris, eds., Regional to wellbore analog for fluvial-deltaic reservoir modelling: The Ferron Sandstone of Utah: AAPG Studies in Geology 50, p. 125–192.

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# Gibbons, K., T. Hellem, A. Kjemperud, S. D. Nio, and K. Vebenstad, 1993, Sequence architecture, facies development and carbonate-cemented horizons in the Troll Field reservoir, offshore Norway, inM. Ashton, ed., Advances in reservoir geology: Geological Society, London, Special Publication 69, p. 1–31.

# Gibbons, K., T. Hellem, A. Kjemperud, S. D. Nio, and K. Vebenstad, 1993, Sequence architecture, facies development and carbonate-cemented horizons in the Troll Field reservoir, offshore Norway, inM. Ashton, ed., Advances in reservoir geology: Geological Society, London, Special Publication 69, p. 1–31.