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The West Texas Super Basin covers more than 57,500 square miles, as outlined in [[:file:M125-WestTexas-Figure1.jpg|Figure 1]], including more than 50 counties in Texas and 5 counties in southern New Mexico. The basin structure covered a much larger geographic extent during various geologic ages, and sedimentation occurred over a much larger area. Structural and stratigraphic boundaries are difficult to define within a single age, let alone throughout basin development. For example, the eastern border of the basin, as illustrated ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]]), is the eastern shelf edge approximate position during the lower Wolfcamp<ref> Brown, L. F., Jr., R. F. Solis Iriate, and D. A. Johns, 1987, Regional stratigraphic cross sections, Upper Pennsylvanian and Lower Permian strata (Virgilian and Wolfcampian Series): North-Central Texas: Bureau of Economic Geology, 27 pages and 27 plates.</ref><ref> Brown, L. F., Jr., R. F. Solis Iriate, and D. A. Johns, 1990, Regional depositional systems tracts, paleogeography, and sequence stratigraphy, Upper Pennsylvanian and Lower Permian strata: North- and West-Central Texas: Bureau of Economic Geology Report of Investigations 197, 116 p.</ref><ref name=Duttn2005a>Dutton, S. P., E. M. Kim, R. F. Broadhead, C. L. Breton, W. D. Raatz, S. C. Ruppel, and C. Kerans, 2005a, Play analysis and digital portfolio of major oil reservoirs in the Permian Basin: Bureau of Economic Geology, Report of Investigations 271, 287 p.</ref>. The eastern shelf of the basin continues to the Bend Arch, the axis of that feature being 150 miles farther east. The Eastern Shelf of the basin is typically treated as a separate geologic providence, and it is not a focus area for unconventional resource reservoirs currently being developed by the oil and gas industry. The features illustrated in [[:file:M125-WestTexas-Figure1.jpg|Figure 1]] and stratigraphic column, [[:file:M125-WestTexas-Figure2.jpg|Figure 2 (A, B)]], provides the framework for the unconventional resource reservoirs, production, reserves, and activity for this work focused on the Spraberry and Wolfcamp in the Midland Basin and Bone Spring and Wolfcamp in the Delaware Basin. Other figures are included to provide the basin framework during the ages, tectonic framework, and stratigraphy presented.

The West Texas Super Basin covers more than 57,500 square miles, as outlined in [[:file:M125-WestTexas-Figure1.jpg|Figure 1]], including more than 50 counties in Texas and 5 counties in southern New Mexico. The basin structure covered a much larger geographic extent during various geologic ages, and sedimentation occurred over a much larger area. Structural and stratigraphic boundaries are difficult to define within a single age, let alone throughout basin development. For example, the eastern border of the basin, as illustrated ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]]), is the eastern shelf edge approximate position during the lower Wolfcamp<ref> Brown, L. F., Jr., R. F. Solis Iriate, and D. A. Johns, 1987, Regional stratigraphic cross sections, Upper Pennsylvanian and Lower Permian strata (Virgilian and Wolfcampian Series): North-Central Texas: Bureau of Economic Geology, 27 pages and 27 plates.</ref><ref> Brown, L. F., Jr., R. F. Solis Iriate, and D. A. Johns, 1990, Regional depositional systems tracts, paleogeography, and sequence stratigraphy, Upper Pennsylvanian and Lower Permian strata: North- and West-Central Texas: Bureau of Economic Geology Report of Investigations 197, 116 p.</ref><ref name=Duttn2005a>Dutton, S. P., E. M. Kim, R. F. Broadhead, C. L. Breton, W. D. Raatz, S. C. Ruppel, and C. Kerans, 2005a, Play analysis and digital portfolio of major oil reservoirs in the Permian Basin: Bureau of Economic Geology, Report of Investigations 271, 287 p.</ref>. The eastern shelf of the basin continues to the Bend Arch, the axis of that feature being 150 miles farther east. The Eastern Shelf of the basin is typically treated as a separate geologic providence, and it is not a focus area for unconventional resource reservoirs currently being developed by the oil and gas industry. The features illustrated in [[:file:M125-WestTexas-Figure1.jpg|Figure 1]] and stratigraphic column, [[:file:M125-WestTexas-Figure2.jpg|Figure 2 (A, B)]], provides the framework for the unconventional resource reservoirs, production, reserves, and activity for this work focused on the Spraberry and Wolfcamp in the Midland Basin and Bone Spring and Wolfcamp in the Delaware Basin. Other figures are included to provide the basin framework during the ages, tectonic framework, and stratigraphy presented.

[[file:M125-WestTexas-Figure1.jpg|center|framed|{{figure number|1}}Map showing the West Texas Super Basin area and locations of basins and platforms during lower Permian. Also shown are important outcrop locations of Permian age strata, modified from Ruppel<ref name=Ruppl2019>Ruppel, S. C., 2019, Anatomy of a Paleozoic Basin: The Permian Basin, USA: Introduction, overview, and evolution, in S. C. Ruppel, ed., Anatomy of a Paleozoic Basin: The Permian Basin, USA: Bureau of Economic Geology, Report of Investigations 285 and AAPG Memoir 118, p. 1–27.</ref>; modified from Dutton et al. <ref name=Duttn2005a /><ref name=Duttn2005b>Dutton, S. P., E. M. Kim, R. F. Broadhead, C. L. Breton, W. D. Raatz, S. C. Ruppel, and C. Kerans, 2005b, [https://archives.datapages.com/data/bulletns/2005/05may/0553/0553.HTM Play analysis and leading edge oil reservoir development methods in the Permian Basin: Increased recovery through advanced technologies]: AAPG Bulletin, v. 89, p. 553–576.</ref>.]]

 

file:M125-WestTexas-Figure1.jpg|{{figure number|1}}Map showing the West Texas Super Basin area and locations of basins and platforms during lower Permian. Also shown are important outcrop locations of Permian age strata, modified from Ruppel<ref name=Ruppl2019>Ruppel, S. C., 2019, Anatomy of a Paleozoic Basin: The Permian Basin, USA: Introduction, overview, and evolution, in S. C. Ruppel, ed., Anatomy of a Paleozoic Basin: The Permian Basin, USA: Bureau of Economic Geology, Report of Investigations 285 and AAPG Memoir 118, p. 1–27.</ref>; modified from Dutton et al. <ref name=Duttn2005a /><ref name=Duttn2005b>Dutton, S. P., E. M. Kim, R. F. Broadhead, C. L. Breton, W. D. Raatz, S. C. Ruppel, and C. Kerans, 2005b, [https://archives.datapages.com/data/bulletns/2005/05may/0553/0553.HTM Play analysis and leading edge oil reservoir development methods in the Permian Basin: Increased recovery through advanced technologies]: AAPG Bulletin, v. 89, p. 553–576.</ref>.

[[file:M125-WestTexas-Figure2.jpg|center|framed|{{figure number|2}}(A) Permian Stratigraphic Column for the West Texas Basin (from Ruppel<ref name=Ruppl2019 />). (B) Pre-Permain Paleozoic Stratigraphic Column for the West Texas Basin (from Ruppel<ref name=Ruppl2019 />).]]

file:M125-WestTexas-Figure2.jpg|{{figure number|2}}(A) Permian Stratigraphic Column for the West Texas Basin (from Ruppel<ref name=Ruppl2019 />). (B) Pre-Permain Paleozoic Stratigraphic Column for the West Texas Basin (from Ruppel<ref name=Ruppl2019 />).

The concept of a basin existing under the expansive deserts of West Texas and southeastern New Mexico only become apparent through speculation from fieldwork and evaluation of water well cuttings during the mid-1910–1920 decade. The West Texas Basin presence was not proven and defined until drilling for hydrocarbons during the 1920s. The first economic subsurface exploration and development after water was for potash. Potash was needed by the United States (mid-1910s) for crop fertilization, having lost supply from Germany during the European War<ref>Phillips, W. B., 1915, Prefatory note, in, J. A. Udden, Potash in the Texas Permian: Bureau of Economic Geology and Technology, Bulletin of the University of Texas, Austin, Texas, v. 17, 59 p.</ref> later to become the Great War, and by the mid–twentieth century known as World War I. Even the Santa Rita #1 in the Big Lake Field was evaluated for its potash potential above 2000’ subsurface before being drilled deeper and discovering oil at a total depth of 3050’ (MD).

The concept of a basin existing under the expansive deserts of West Texas and southeastern New Mexico only become apparent through speculation from fieldwork and evaluation of water well cuttings during the mid-1910–1920 decade. The West Texas Basin presence was not proven and defined until drilling for hydrocarbons during the 1920s. The first economic subsurface exploration and development after water was for potash. Potash was needed by the United States (mid-1910s) for crop fertilization, having lost supply from Germany during the European War<ref>Phillips, W. B., 1915, Prefatory note, in, J. A. Udden, Potash in the Texas Permian: Bureau of Economic Geology and Technology, Bulletin of the University of Texas, Austin, Texas, v. 17, 59 p.</ref> later to become the Great War, and by the mid–twentieth century known as World War I. Even the Santa Rita #1 in the Big Lake Field was evaluated for its potash potential above 2000’ subsurface before being drilled deeper and discovering oil at a total depth of 3050’ (MD).

During the mid-2000s through 2009, Eagle Oil & Gas Co., a Texas Independent, made a capital expenditure of approximately $70 MM drilling geologically successful, subeconomic wells in south Texas and the southern West Texas Basin. Eagle’s 40,000–50,000 acres in the West Texas Basin were scattered over Reeves, Pecos, and Ward Counties in the southern Delaware Basin, southern Central Basin Axis, and deep Sheffield Channel ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]]). Their objectives at that time were conventional reservoirs in Pennsylvanian sandstones on the margin of the Central Basin Axis into the Sheffield Channel, Wolfcamp C sandstones sourced from the Diablo Platform filling the western margin of the abruptly subsiding southern Delaware Basin ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B, C]]), and Third Bone Spring sandstones in central Reeves and southern Ward Counties ([[:file:M125-WestTexas-Figure8.jpg|Figure 8]]).

During the mid-2000s through 2009, Eagle Oil & Gas Co., a Texas Independent, made a capital expenditure of approximately $70 MM drilling geologically successful, subeconomic wells in south Texas and the southern West Texas Basin. Eagle’s 40,000–50,000 acres in the West Texas Basin were scattered over Reeves, Pecos, and Ward Counties in the southern Delaware Basin, southern Central Basin Axis, and deep Sheffield Channel ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]]). Their objectives at that time were conventional reservoirs in Pennsylvanian sandstones on the margin of the Central Basin Axis into the Sheffield Channel, Wolfcamp C sandstones sourced from the Diablo Platform filling the western margin of the abruptly subsiding southern Delaware Basin ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B, C]]), and Third Bone Spring sandstones in central Reeves and southern Ward Counties ([[:file:M125-WestTexas-Figure8.jpg|Figure 8]]).

[[file:M125-WestTexas-Figure7.jpg|center|framed|{{figure number|7}}(A) Blakey reconstruction of the West Texas Basin during Middle Permian and cross-section locations in the Delaware Basin. (B) Cross section A-A’, north to south showing the low-stand, stratigraphic interval, Wolfcamp C in blue. A similar geometry from west to east (dashed line) occurs as represented on the southern half of cross section A-A’. (C) Gamma Ray–Density-Neutron log across the Wolfcamp C showing a representative sandstone, 9’ thick, 14% average porosity with good Neutron–Density crossover. Darker horizontal lines indicate 10’ of depth separation; lighter horizontal lines show 2’ depth separation. 7A and 7B modified from Carr<ref name=Carr>Carr, D. L., 2019, Stratigraphic architecture and facies of the Bone Spring Formation (Permian), Delaware Basin, New Mexico and Texas, in W. Fairhurst, ed., Tight Oil Resource Assessment Research Consortium (TORA) Annual Meeting, May 8–9, 2019, p. 1–10.</ref>]].

 

file:M125-WestTexas-Figure7.jpg|{{figure number|7}}(A) Blakey reconstruction of the West Texas Basin during Middle Permian and cross-section locations in the Delaware Basin. (B) Cross section A-A’, north to south showing the low-stand, stratigraphic interval, Wolfcamp C in blue. A similar geometry from west to east (dashed line) occurs as represented on the southern half of cross section A-A’. (C) Gamma Ray–Density-Neutron log across the Wolfcamp C showing a representative sandstone, 9’ thick, 14% average porosity with good Neutron–Density crossover. Darker horizontal lines indicate 10’ of depth separation; lighter horizontal lines show 2’ depth separation. 7A and 7B modified from Carr<ref name=Carr>Carr, D. L., 2019, Stratigraphic architecture and facies of the Bone Spring Formation (Permian), Delaware Basin, New Mexico and Texas, in W. Fairhurst, ed., Tight Oil Resource Assessment Research Consortium (TORA) Annual Meeting, May 8–9, 2019, p. 1–10.</ref>.

[[file:M125-WestTexas-Figure8.jpg|center|framed|{{figure number|8}}Third Bone Spring sandstone. (A) Third Bone Spring sandstone Type Log showing Hoban, A, and C sandstones (B sandstone is not developed at this type log location; D/E not illustrated). (B) Cross section B-B’ is located from central Reeves County on the south to southern Ward County on the north (see location on the map, ([[:file:M125-WestTexas-Figure7.jpg|Figure 7A]]). The Hoban, A, and C sandstones are well developed on the south end of cross section B-B’ in central Reeves County, and there are no lower sandstones D/E to the south. The upper sandstones pinch out to the north in southern Ward County, but the lower sandstones D/E are present immediately above the Wolfcamp Shale (stratigraphic cross section B-B’ is hung on the red line, Bone Spring–Wolfcamp contact). Cross section B-B’ modified after Masterson<ref>Masterson, R., 2010, North-South geologic cross section of the 3rd bone spring sandstones: Reeves and Ward Counties, Eagle Oil & Gas, 1 plate.</ref>.]]

file:M125-WestTexas-Figure8.jpg|{{figure number|8}}Third Bone Spring sandstone. (A) Third Bone Spring sandstone Type Log showing Hoban, A, and C sandstones (B sandstone is not developed at this type log location; D/E not illustrated). (B) Cross section B-B’ is located from central Reeves County on the south to southern Ward County on the north (see location on the map, ([[:file:M125-WestTexas-Figure7.jpg|Figure 7A]]). The Hoban, A, and C sandstones are well developed on the south end of cross section B-B’ in central Reeves County, and there are no lower sandstones D/E to the south. The upper sandstones pinch out to the north in southern Ward County, but the lower sandstones D/E are present immediately above the Wolfcamp Shale (stratigraphic cross section B-B’ is hung on the red line, Bone Spring–Wolfcamp contact). Cross section B-B’ modified after Masterson<ref>Masterson, R., 2010, North-South geologic cross section of the 3rd bone spring sandstones: Reeves and Ward Counties, Eagle Oil & Gas, 1 plate.</ref>.

Cross section A-A’ ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B]]) is north–south through the center of the Delaware Basin. It is hung on the top of the Bone Spring formation showing the Bone Spring and Wolfcamp filling the abruptly subsiding Delaware Basin. The Wolfcamp C (blue) is the thickest, onlapping basin-filling, low-stand stratigraphic interval. In southern Reeves County, the Wolfcamp C thins dramatically onto the Diablo Platform ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]], [[:file:M125-WestTexas-Figure7.jpg|Figure 7A]]), and a dashed cross section (A-A’) is illustrated, showing a similar geometry as displayed on the southern part of cross section A-A’. Wells that penetrate the Wolfcamp C closer to the Diablo Platform are up to 75% sandstone with high resistivity and typically have 5–10 ft flairs while drilling ([[:file:M125-WestTexas-Figure7.jpg|Figure 7C]]). To the east into the basin, farther from the source, the sandstone percentages decrease, but the reservoir quality, resistivity, and 5–10 ft flairs are consistent, with an increased or uniform thickness of the entire interval. Where productive, these sandstone reservoirs and older, Pennsylvanian sandstone reservoirs produce 1 BCFG per foot from conventional reservoir porosity.

Cross section A-A’ ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B]]) is north–south through the center of the Delaware Basin. It is hung on the top of the Bone Spring formation showing the Bone Spring and Wolfcamp filling the abruptly subsiding Delaware Basin. The Wolfcamp C (blue) is the thickest, onlapping basin-filling, low-stand stratigraphic interval. In southern Reeves County, the Wolfcamp C thins dramatically onto the Diablo Platform ([[:file:M125-WestTexas-Figure1.jpg|Figure 1]], [[:file:M125-WestTexas-Figure7.jpg|Figure 7A]]), and a dashed cross section (A-A’) is illustrated, showing a similar geometry as displayed on the southern part of cross section A-A’. Wells that penetrate the Wolfcamp C closer to the Diablo Platform are up to 75% sandstone with high resistivity and typically have 5–10 ft flairs while drilling ([[:file:M125-WestTexas-Figure7.jpg|Figure 7C]]). To the east into the basin, farther from the source, the sandstone percentages decrease, but the reservoir quality, resistivity, and 5–10 ft flairs are consistent, with an increased or uniform thickness of the entire interval. Where productive, these sandstone reservoirs and older, Pennsylvanian sandstone reservoirs produce 1 BCFG per foot from conventional reservoir porosity.

</ref><ref name=Peppr2020b>Pepper, A. S., E. Rhoden, P. Foy, H. Ross, J. M. Laigle, and C. Yarbrough, 2020b, Petroleum systems modeling of Wolfcamp Formation reservoir fluid saturations and compositions in the Delaware Basin: Key principles and workflows: West Texas Geological Society Annual Fall Symposium, September 23, 2020.</ref>.

</ref><ref name=Peppr2020b>Pepper, A. S., E. Rhoden, P. Foy, H. Ross, J. M. Laigle, and C. Yarbrough, 2020b, Petroleum systems modeling of Wolfcamp Formation reservoir fluid saturations and compositions in the Delaware Basin: Key principles and workflows: West Texas Geological Society Annual Fall Symposium, September 23, 2020.</ref>.

Once the gross shale (Wolfcamp A and B) interval was mapped, the focus shifted to individual horizons within the Wolfcamp A and B. The model was that the basin-floor depositional system contained the organic-rich, silica-rich, very thinly bedded basinal facies with shelf carbonate debris flows into the basin. Very different interpretations of the Wolfcamp were made, depending on what part of the depositional systems within the basin the geologist were most familiar. In outcrop in the Glass Mountains along the southern margin of the West Texas Basin and the Guadalupe Mountains on the basin western margin, the Wolfcamp is dominantly shelf carbonates with minor interbedded siliciclastic shales. The basin center is dominantly the in situ thinly bedded siliciclastic, organic-rich mudstones with the allochthonous shelf carbonate debrites and turbidites. In the Wolfcamp B, the allochthonous carbonates were debrites with coarse shelf clasts in a lime matrix and were easily identifiable in cuttings and imaging logs ([[:file:M125-WestTexas-Figure13.jpg|Figure 13]]). These commonly massively thick (>100’) agglomerated units contained very little organic material. It was interpreted that shelf carbonate gravity flows would continue down the constant angle slope until hitting the basin floor (red line on [[:file:M125-WestTexas-Figure12.jpg|Figure 12B]], [[:file:M125-WestTexas-Figure13.jpg|13B]]), then deaccelerate, depositing the sediment load.

Once the gross shale (Wolfcamp A and B) interval was mapped, the focus shifted to individual horizons within the Wolfcamp A and B. The model was that the basin-floor depositional system contained the organic-rich, silica-rich, very thinly bedded basinal facies with shelf carbonate debris flows into the basin. Very different interpretations of the Wolfcamp were made, depending on what part of the depositional systems within the basin the geologist were most familiar. In outcrop in the Glass Mountains along the southern margin of the West Texas Basin and the Guadalupe Mountains on the basin western margin, the Wolfcamp is dominantly shelf carbonates with minor interbedded siliciclastic shales. The basin center is dominantly the in situ thinly bedded siliciclastic, organic-rich [[mudstones]] with the allochthonous shelf carbonate debrites and turbidites. In the Wolfcamp B, the allochthonous carbonates were debrites with coarse shelf clasts in a lime matrix and were easily identifiable in cuttings and imaging logs ([[:file:M125-WestTexas-Figure13.jpg|Figure 13]]). These commonly massively thick (>100’) agglomerated units contained very little organic material. It was interpreted that shelf carbonate gravity flows would continue down the constant angle slope until hitting the basin floor (red line on [[:file:M125-WestTexas-Figure12.jpg|Figure 12B]], [[:file:M125-WestTexas-Figure13.jpg|13B]]), then deaccelerate, depositing the sediment load.

[[file:M125-WestTexas-Figure13.jpg|center|framed|{{figure number|13}}Thinly bedded, organic-rich, silica facies, and Sheldon Carbonate. (A) Nine (9’) foot vertical image of a Schlumberger FMI (Formation Micro-Imaging Log) in the lower Wolfcamp B. Upper part in the organic-rich, siliceous mudstone. Individual silica-rich beds are millimeters thick. The lower half is the Sheldon Carbonate, a massive (more than 100’ thick) non-bedded, amalgamated debrite. Individual shelf clast can be seen (white and black) floating in the shelf mud matrix. (B) Hanson’s<ref name=Hansn2010 /> isochore map of the Sheldon Carbonate (C.I. = 10’), approximately 54’ gross; 39’ net on the attached Gamma Ray, Neutron–Density Log (dark horizontal lines on the log indicate 10’ vertically; the lighter lines are 2’ vertically on the log). Note the orientation of the debrite oriented subparallel to the slope–basin-floor contact. Other carbonate debrite subfacies isochores have similar subparallel and channel feeder facies perpendicular to the slope, including interpretations mapped by Scott Hamlin<ref name=FairhrstHamln>Fairhurst, B., and S. Hamlin, 2018, Stratigraphic observations of the upper Wolfcampian shale (A&B), Southern Delaware Basin, West Texas: Variations in stratigraphy, depositional processes, mineral facies and log measurements, in W. Fairhurst, ed., Tight Oil Resource Assessment (TORA) Annual Meeting: Bureau of Economic Geology, March 26, p. 91–110.</ref> (reprinted with permission) at the southwest corner of the merging western and southern slope to basin environments just south of this map area.]]

[[file:M125-WestTexas-Figure13.jpg|center|framed|{{figure number|13}}Thinly bedded, organic-rich, silica facies, and Sheldon Carbonate. (A) Nine (9’) foot vertical image of a Schlumberger FMI (Formation Micro-Imaging Log) in the lower Wolfcamp B. Upper part in the organic-rich, siliceous mudstone. Individual silica-rich beds are millimeters thick. The lower half is the Sheldon Carbonate, a massive (more than 100’ thick) non-bedded, amalgamated debrite. Individual shelf clast can be seen (white and black) floating in the shelf mud matrix. (B) Hanson’s<ref name=Hansn2010 /> isochore map of the Sheldon Carbonate (C.I. = 10’), approximately 54’ gross; 39’ net on the attached Gamma Ray, Neutron–Density Log (dark horizontal lines on the log indicate 10’ vertically; the lighter lines are 2’ vertically on the log). Note the orientation of the debrite oriented subparallel to the slope–basin-floor contact. Other carbonate debrite subfacies isochores have similar subparallel and channel feeder facies perpendicular to the slope, including interpretations mapped by Scott Hamlin<ref name=FairhrstHamln>Fairhurst, B., and S. Hamlin, 2018, Stratigraphic observations of the upper Wolfcampian shale (A&B), Southern Delaware Basin, West Texas: Variations in stratigraphy, depositional processes, mineral facies and log measurements, in W. Fairhurst, ed., Tight Oil Resource Assessment (TORA) Annual Meeting: Bureau of Economic Geology, March 26, p. 91–110.</ref> (reprinted with permission) at the southwest corner of the merging western and southern slope to basin environments just south of this map area.]]

The following difference between Wolfcamp A and B were identified and defined in [[:file:M125-WestTexas-Figure15.jpg|Figures 15]], [[:file:M125-WestTexas-Figure16.jpg|16]], [[:file:M125-WestTexas-Figure17.jpg|17]] and [[:file:M125-WestTexas-Table1.jpg|Table 1]]<ref name=FairhrstHamln />.

The following difference between Wolfcamp A and B were identified and defined in [[:file:M125-WestTexas-Figure15.jpg|Figures 15]], [[:file:M125-WestTexas-Figure16.jpg|16]], [[:file:M125-WestTexas-Figure17.jpg|17]] and [[:file:M125-WestTexas-Table1.jpg|Table 1]]<ref name=FairhrstHamln />.

[[file:M125-WestTexas-Figure16.jpg|center|framed|{{figure number|16}}Stratigraphic column Upper Pennsylvanian to Lower Permian from Fu et al.<ref> Fu, Q., R. W. Baumgardner Jr., and H. S. Hamlin, 2020, Early Permian (Wolfcampian) succession in the Permian Basin: Icehouse platform, slope carbonates, and basinal mudrocks, in S. C. Ruppel, ed., Anatomy of a Paleozoic Basin: The Permian Basin, USA: Bureau of Economic Geology Report of Investigations 285 and AAPG Memoir 118, p. 185–225.

</ref> (reprinted with permission). The Wolfcamp A is 50% thicker in the Delaware Basin than in the Midland Basin, the Wolfcamp B in the Delaware and Midland Basins are similar thickness, and the Wolfcamp C thicknesses vary considerably by locality ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B]]), typically reaching maximum thickness in the southern parts of both basins. The Wolfcamp D (Cline) is the Missourian–Virgilian stage; Canyon–Cisco stratigraphic equivalents in the West Texas Basin. Canyon–Cisco stratigraphic terminology is used on the basin margins; Wolfcamp D (Cline) terminology is used for the deep-basin, basin-floor facies.]]

file:M125-WestTexas-Figure16.jpg|{{figure number|16}}Stratigraphic column Upper Pennsylvanian to Lower Permian from Fu et al.<ref> Fu, Q., R. W. Baumgardner Jr., and H. S. Hamlin, 2020, Early Permian (Wolfcampian) succession in the Permian Basin: Icehouse platform, slope carbonates, and basinal mudrocks, in S. C. Ruppel, ed., Anatomy of a Paleozoic Basin: The Permian Basin, USA: Bureau of Economic Geology Report of Investigations 285 and AAPG Memoir 118, p. 185–225.

 

</ref> (reprinted with permission). The Wolfcamp A is 50% thicker in the Delaware Basin than in the Midland Basin, the Wolfcamp B in the Delaware and Midland Basins are similar thickness, and the Wolfcamp C thicknesses vary considerably by locality ([[:file:M125-WestTexas-Figure7.jpg|Figure 7B]]), typically reaching maximum thickness in the southern parts of both basins. The Wolfcamp D (Cline) is the Missourian–Virgilian stage; Canyon–Cisco stratigraphic equivalents in the West Texas Basin. Canyon–Cisco stratigraphic terminology is used on the basin margins; Wolfcamp D (Cline) terminology is used for the deep-basin, basin-floor facies.

[[file:M125-WestTexas-Figure17.jpg|center|framed|{{figure number|17}}Scott Hamlin’s<ref name=FairhrstHamln /> (reprinted with permission) quick-look open-hole log mineral facies identification for the Wolfcamp confirmed with XRF from whole core. Note the siliceous and calcareous mudrock dominance and higher total TOC in the Wolfcamp A versus argillaceous mudrock and lower TOC in the Wolfcamp B. Also shown are the thicker, amalgamated debrites, carbonate facies in the Wolfcamp B and thin to very thinly bedded turbidite, carbonates facies in the Wolfcamp A. A type log showing the typical oil industry division of the Wolfcamp A and B in the Delaware Basin. The Wolfcamp A1 is present in northern Reeves, Loving, Winkler, and Ward Counties and not present in southern Reeves and Pecos Counties (from Gherabati et al.,<ref name=Gherbtietal2019>Gherabati, A., K. Smye, G. McDaid, and S. Hamlin, 2019, Developing a depletion score to study well spacing and the parent–child effect, in E. Goodman, ed., Tight Oil Resource Assessment Research Consortium Annual Meeting: Bureau of Economic Geology, November 20–21, p. 37–44.</ref> reprinted with permission).]]

file:M125-WestTexas-Figure17.jpg|{{figure number|17}}Scott Hamlin’s<ref name=FairhrstHamln /> (reprinted with permission) quick-look open-hole log mineral facies identification for the Wolfcamp confirmed with XRF from whole core. Note the siliceous and calcareous mudrock dominance and higher total TOC in the Wolfcamp A versus argillaceous mudrock and lower TOC in the Wolfcamp B. Also shown are the thicker, amalgamated debrites, carbonate facies in the Wolfcamp B and thin to very thinly bedded turbidite, carbonates facies in the Wolfcamp A. A type log showing the typical oil industry division of the Wolfcamp A and B in the Delaware Basin. The Wolfcamp A1 is present in northern Reeves, Loving, Winkler, and Ward Counties and not present in southern Reeves and Pecos Counties (from Gherabati et al.,<ref name=Gherbtietal2019>Gherabati, A., K. Smye, G. McDaid, and S. Hamlin, 2019, Developing a depletion score to study well spacing and the parent–child effect, in E. Goodman, ed., Tight Oil Resource Assessment Research Consortium Annual Meeting: Bureau of Economic Geology, November 20–21, p. 37–44.</ref> reprinted with permission).

 

file:M125-WestTexas-Table1.jpg|'''Table 1''' Total Organic Carbon, Mineral Facies, Clay, and Open-Hole Log Differences Noted in the Wolfcamp A and B (Fairhurst and Hamlin<ref name=FairhrstHamln /> reprinted with permission).

[[file:M125-WestTexas-Table1.jpg|center|framed|’’’Table 1’’’Total Organic Carbon, Mineral Facies, Clay, and Open-Hole Log Differences Noted in the Wolfcamp A and B (Fairhurst and Hamlin<ref name=FairhrstHamln /> reprinted with permission).]]

Drilling vertical wells, running complete log suites, obtaining core, and testing completion techniques in various intervals provided data and information to solve rock property, completion techniques, and productivity of multiple horizons and facies. During that process, Eagle drilled and completed 26 vertical wells and participated in another half dozen outside operated vertical wells before drilling the first horizontal well in the Wolfcamp unconventional reservoirs in the southern Delaware Basin. By 2012, the Midland Basin zonal definitions of the Wolfcamp ([[:file:M125-WestTexas-Figure16.jpg|Figure 16]]) were being identified and used by the industry in the Delaware Basin.

Drilling vertical wells, running complete log suites, obtaining core, and testing completion techniques in various intervals provided data and information to solve rock property, completion techniques, and productivity of multiple horizons and facies. During that process, Eagle drilled and completed 26 vertical wells and participated in another half dozen outside operated vertical wells before drilling the first horizontal well in the Wolfcamp unconventional reservoirs in the southern Delaware Basin. By 2012, the Midland Basin zonal definitions of the Wolfcamp ([[:file:M125-WestTexas-Figure16.jpg|Figure 16]]) were being identified and used by the industry in the Delaware Basin.