Wasson Basin

(Figure 1) Location of Wasson Field Basin in West Texas Permian Basin. Retrieved from https://peakoil.com/production/why-we-can-expect-cripplingly-higher-oil-prices

Introduction

The Wasson Basin is located in Gaines and Yoakum Counties on the Llano Estacado or commonly called the Staked Plains of West Texas. It is a Sub-Basin in the West Texas Permian Basin, one of the oldest and well-known hydrocarbon producing areas (See Figure 1). Discovered in 1936 and drilled by the Honolulu Oil Corporation and Davidson Company, the Wasson field is a triangular-shaped oil and gas producing area that is 15 miles long and 14 miles wide and comprises of 59,000 acres. The Wasson Basin is structurally controlled by a NW-SE trending Permian structural axis and by the Wichita-Albany shelf margin.

History

The location that Honolulu and Davidson drilled the first well in the Wasson Basin was thirty-five miles to the southwest of the nearest producing site in Lea County, New Mexico. The cost of transporting the production thirty-five miles threatened profits as crude oil only sold for 84 cents a barrel in West Texas in 1936. In 1937, Humble Pipe Line Company built a line to connect the field with its terminal in Hobbs, New Mexico so transporting production was only an issue for the first year. In June of 1937 Amon G. Carter Sr. drilled the Wasson No. 1 which was the discovery well in the South part of the basin. By the end up 1937, the Wasson Basin reported twenty-six producing wells and a yearly production of 314,024 barrels of oil. Continental Oil Company and the Denver Producing and Refining Company began producing in surrounding areas called Clawater, Dowden, Baumgart, Kendrick, and Roberts and all the reservoirs in these plays were found. In 1939 the Railroad Commission combined all of these producing fields under the name the Wasson Basin and reached drilling of more than nine million barrels of oil and 729 wells. By the 1940s the main expansion on the forty acres well spacing was finished and operators started deep drilling tests to tap zones below known production. Peak production came in 1948 when over 28.1 million barrels was produced from 1,588 wells. Production fell in the 1950s and 60s due to cheap crude prices. In the 1970s infill drilling took place to reach oil in plays that were not exploited by water-flooding. By 1992 the Wasson field was producing 1,823,664,000 barrels of oil from 2,242 wells which made it the largest producer in West Texas, and the second largest producer in Texas.

(Figure 2) Wasson Field Tertiary CO2 Flooding in the 1980s. Retrieved from http://www.co2storagesolutions.com/Download_Files/Merchant_CO2_WAG_History_Paper_August_2017.pdf

Geology

The Wasson Basin lies on the stretched axis of the Central Basin platform and separated by a trough in Northern Gaines County Texas. There are two major axes in the basin with one moving North 60 degrees West and the other North 30 degrees East to form the structure of the Wasson field. The physical elements give the appearance of the field to be pointed northeast by post-Permian movements. The blend of the Permian structure and the stratigraphy controls the permeability, porosity, and accumulation of fluids in the basin. The stratigraphic features of the basin are similar to most other West Texas fields where large, porous, dolomites with very few clastic present and move into thicker sections of interbedded anhydrite and dolomite that contain more clastic material. There is no relationship between the structural elevation of the basin and the ability to produce oil.

Geologic Risks and Petroleum Engineering Aspects

The prime production in the Wasson Basin lasted from 1937 till the mid 1960s with peak production in 1948. By the 1950s the oil rate began to decline and reservoir pressure depleted. In 1965 operators instituted one of the United States largest water-flooding projects by initiating pressure maintenance with water injection. When the water broke through at the production wells the volume of water produced rose exponentially. In the 1970s tertiary rock recovery was done by a carbon dioxide injection plan that pulled around 1.3 billion barrels of oil left from water-flooding and carbon dioxide enhanced oil recovery infill drilling. In 1982, the volumes of water being injected and produced exceeded the amount of oil produced, but after initiating carbon dioxide injections in 1983, oil production leveled off and eventually produced more oil than water. By 1998 engineers were able to determine the incremental oil attributable to carbon dioxide enhanced oil recovery by calculating the difference between the projected decline rate without carbon dioxide injection and the actual production rate (See Figure 2). The plan was called the Denver Unit Carbon Dioxide Enhanced Oil Recovery Project and has been the leading producer of oil in the Wasson Basin the past fifty years.

Petroleum Elements

Source Rock & Migration

The source rocks in the Wasson Basin consists of: Cretaceous, Recent, Tertiary, Triassic, and Permian rocks. The reservoir is in porous dolomite from 300 to 600 feet below the top of the San Andres formation. Well cuttings show the body of the reservoir to have a reef-like cross section that is from reef growth with attendant chemical deposition and recrystallization of the dolomite. Hydrocarbons migrated laterally and upward into the present porous reservoir rocks right after generation. It is likely that the source rock immediately began to produce oil and gas after the reservoir was sealed. Younger source rocks of Pennsylvanian and Permian organic rich shales added additional hydrocarbons to create migration paths. Fluids are migrated laterally and upward into the present reservoirs.

Reservoirs

The sediments that make up the reservoirs are deposited in a distant back shelf restricted marine environment. The sedimentary sequence was deposited during a regression and the whole reservoir is dolomitized completely. Porosity is established mainly in the restricted marine facies and also in the intertidal facies. The reservoir is capped by nonporous supratidal facies. Permeable porosity in the marine facies turn into particulate, unsorted, sediments. Destruction of the porosity is common by secondary anhydrites. Individual porous beds are irregular and thin but better developed by axes of buried physical structures.

(Figure 3) Example of a rig in West Texas Permian Basin. Retrieved from https://www.chron.com/business/energy/article/West-Texas-Permian-Basin-leads-yet-another-rig-14402429.php.

Seals and Traps

Seals are provided by the salt beds, anhydrite, nonporous dolomites, and red beds. Operative seals are developed by the dolomite, shale carbonate, anhydrite, and other evaporite facies. Traps are primary stratigraphic and also a blend of structural and stratigraphic. Stratigraphic traps in the shelf are developed by lateral facies changes into nonporous and permeable strata. Structural traps are usually anticlinal closures that had topographic relief and buried reef traps. The depositional structures that control the traps as well as the seals completing the traps in the Wasson Basin were created at the end of Permian Guadeloupean time.

Future Petroleum Potential

With prime production of the well lasting from around 1937 to 1949, the Wasson Basin is one of the lower producing reservoirs in West Texas today. Since 2008, the Wasson Area has known recoverable oil of around three thousand MMBL (million barrels of oil) and estimated recovery efficiency average of thirty three percent (See Figure 3). The Wasson Field’s main production today is from the Denver Unit Carbon Dioxide Enhanced Oil Recovery Project that has produced more than 120 million barrels of oil thru 2008.

Further Readings and External Links

1. Permian Basin Geology Information
2. Enhanced Oil Recovery
3. Permian Basin Key Facts and Figures, Oil Industry Insight
4. Permian Basin is the most affected play in the US since the beginning of the Covid-19 pandemic

References

1. Schneider, W. (1943, April 01). Geology of Wasson Field, Yoakum and Gaines Counties, Texas. Retrieved November 19, 2020, from https://pubs.geoscienceworld.org/aapgbull/article-abstract/27/4/479/546584/Geology-of-Wasson-Field-Yoakum-and-Gaines-Counties
2. Smith, J. (n.d.). Wasson Field. Retrieved November 19, 2020, from https://www.tshaonline.org/handbook/entries/wasson-field
3. Schneider, W. (1943, April 01). Geology of Wasson Field, Yoakum and Gaines Counties, Texas. Retrieved November 19, 2020, from https://pubs.geoscienceworld.org/aapgbull/article-abstract/27/4/479/546584/Geology-of-Wasson-Field-Yoakum-and-Gaines-Counties
4. Energy, U. (2010, March). Carbon Dioxide Enhanced Oil Recovery. Retrieved November 19, 2020, from https://www.netl.doe.gov/sites/default/files/netl-file/CO2_EOR_Primer.pdf
5. Schneider, W. (1943, April 01). Geology of Wasson Field, Yoakum and Gaines Counties, Texas. Retrieved November 19, 2020, from https://pubs.geoscienceworld.org/aapgbull/article-abstract/27/4/479/546584/Geology-of-Wasson-Field-Yoakum-and-Gaines-Counties
6. Ball, M. M. (n.d.). PERMIAN BASIN PROVINCE (044). Retrieved November 19, 2020, from https://certmapper.cr.usgs.gov/data/noga95/prov44/text/prov44.pdf
7. Coupal, F. (1969, March 01). Geology of San Andres (Permian) Reservoir of Part of Wasson Field, Gaines and Yoakum Counties, Texas. Retrieved November 19, 2020, from https://pubs.geoscienceworld.org/aapgbull/article-abstract/53/3/714/553203/Geology-of-San-Andres-Permian-Reservoir-of-Part-of?redirectedFrom=fulltext
8. Petroleum System of the Upper Permian - Permian Basin. (2013, February 13). Retrieved November 19, 2020, from http://www.sepmstrata.org/page.aspx?pageid=138
9. Ball, M. M. (n.d.). PERMIAN BASIN PROVINCE (044). Retrieved November 19, 2020, from https://certmapper.cr.usgs.gov/data/noga95/prov44/text/prov44.pdf
10. Tennyson, M. E. (2012, March 07). Assessment of Remaining Recoverable Oil in Selected Major Oil Fields of the Permian Basin, Texas and New Mexico. Retrieved November 19, 2020, from https://pubs.usgs.gov/fs/2012/3051/fs2012-3051.pdf
11. Energy, U. (2010, March). Carbon Dioxide Enhanced Oil Recovery. Retrieved November 19, 2020, from https://www.netl.doe.gov/sites/default/files/netl-file/CO2_EOR_Primer.pdf