Dwight Ingram

Oil and Gas Specialist - Worldwide Consultant - 32 years experience - Based in Denver, Colorado

Colorado: 303-726-5663
Florida: 904-310-9495


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Bluff Bench Prospect

Bluff Bench Project Area
Southern Paradox Basin
San Juan County, Utah

Executive Summary

Dwight A. Ingram et al has identified two (2) Lower Ismay/Desert Creek drillsites covering approximately 1500 net acres in the Bluff Bench Area of San Juan County,  Utah, on the southwest shelf of the Paradox Basin.

Production occurs in algal mounds and shoals of the Pennsylvanian Lower Ismay and Desert Creek Formations, which formed in a shallow marine shelf environment.

The prospect area is a classic example where earlier abandoned tests were later recognized as productive yet believed to be non-commercial.

Potential recoverable reserves average 250-350 MBO per well and can reach more than 700 MBO per well.

The target field size is 4-5 wells with combined total reserves of 1.5-2.0 MMBO.

Enhanced oil recovery applications are currently being investigated by a multidisciplinary team led by the Utah Geological Survey. The project hopes to demonstrate both the technical and economic feasability of enhanced oil recovery techniques which could be applied to the more than 50 small fields in the southern Paradox Basin.

Recent prolific short radius, multi-lateral, completions within the Aneth Field complex have resulted in efficient use of new drilling and completion technologies in a mature waterflood.

3-D seismic applications will optimize future development drilling operations. Conventional CDP seismic has been successful in imaging algal mounds, indicating 3-D can be used to further define more complex mound geometries and smaller features.

The dual pay potential combined with shallow drilling depths makes the area an attractive, low risk exploratory drilling opportunity.


The Bluff Bench Prospect is located in the Paradox Basin of southeast Utah in San Juan County. The first oil discovery in the Paradox Basin was in 1908, near Mexican Hat, Utah. The discovery was drilled near an active oil seep, and production was established in shallow sands of the upper Pennsylvanian. Algal mounds have been the successful target of exploratory activities since the early 1950's. Aneth Field was discovered in 1956, and when the magnitude of the field was recognized, exploration activity intensified, resulting in the discovery of numerous smaller fields. These fields typically are developed with one to four wells with primary production ranging from 500-2000 MBO. Geologically, the Prospect Area is on the southwest shelf of the Paradox Basin. Oil and gas production occurs in a series of shelf carbonate cycles of the Ismay and Desert Creek Formations.

The Paradox Basin is a depositional basin which developed primarily during Pennsylvanian time. The basin is elongate with a northwest trending axis. Evaporites accumulated in the interior of the basin during part of the Pennsylvanian time. While salt was being deposited in the basin center, carbonates accumulated on the southwest shelf.


Productive algal mound trends in the Aneth Area of the southwest shelf of the Paradox Basin area related to broad, basement related, low-relief anticlinal features. These structures influenced the development of algal mounds but play a subordinate role to stratigraphic controls on hydrocarbon production. The controls on the development of the mounds on the southwest shelf were water depth, prevailing currents, wave energy, and paleostructural position. Present regional dip is to the east-northeast at about 100' per mile.


The primary objective of the play is the "stacked" algal buildups of the Lower Ismay and Desert Creek Formations. The offsetting well control suggests that these buildups are flat bottomed, low relief, bar-like carbonate banks with elongate geometry's which reach 60-70' maximum thickness. The buildups are enclosed by impermeable carbonates, shales, and evaporites. A Lower Ismay and Desert Creek algal bank complex has been identified throughout the Bluff Bench Area. Heterogeneity and multiple mound facies have been identified in studies conducted by the Utah Geological Survey. Model of Complex Mound Geometry

The Desert Creek Formation is a complex heterogeneous carbonates deposited in a repeating series of mudstones and evaporites between algal mounds and ooilitic shoals. Cycles in deposition were primarily controlled by rapid marine transgressions and slow, interrupted regressions resulting from periods of ice cap building. These cycles were additionally influenced by regional tectonic activity, basin subsidence, proximity to basin margin or evaporites,episodic blockage of open marine waterways, and local fluctuations of water energy. Thickness of the entire interval range from about 100' to more than 150' in the prospect area, grading from a basal, normal marine, into mostly limestones, occasionally dolomitized limestones, overlain by anhydrite. Black shales both under and overlie the zone. Inter-mound troughs occur as tidal channels and add the overall heterogeneity of the complex. Porous intervals within the Desert Creek are described as light-gray to tan, fossil fragment limestone. Intercrystalline porosity ranges from poor to good. Vuggy porosity and natural fractures may also be present.

Shelf Facies Depositional Model

The best reservoirs are associated with mud poor phylliod algal buildups. These are widely distributed, small in areal extent, and can be recognized seismically. Ivanovia is the typical algal plate material. Stylolitization often occurs and influences vertical permeability. Flanking carbonates, tidal channel carbonate sands, and associated depositional features have lacked sufficient porosity and permeability to be important reservoirs. See Model


Initial porosity and permeability seen in the buildup type reservoirs are inferred to have been high in the grain supported, mud deficient algal carbonates. Some porosity may be due to solution, with the distribution of leaching being affected by the original properties. Inter-particle porosity occurs in the more permeable reservoir rocks. Moldic porosity is also common. Porosity can be reduced by calcite or anhydrite infill of early diagenetic origin. Drillstem tests and conventional downhole logs will accurately characterize the reservoirs.

Type Log

Permeabilties from cored wells on the southwest shelf in the Bluff Bench Areas range from less than 0.1 md to more than 100 md. Generally, algal plate type reservoirs with high permeabilty may be associated with low log calculated porosity. Productive zones are characterized by a low gamma ray log response.

Reserves and Economics

Total drilling depths throughout the prospect area are about 5800'. Drilling costs for the initial test will be approximately $175,000.00. Drillstem tests and open hole logs can successfully be used to evaluate productivity potential. Completion expenses, including 5 1/2" production casing, perforating, zone treatment, and surface equipment will total $225,000.00. The total successful well cost is $400,000.00. Initial flow rates are in the 250 BOPD range and potential reserves are 350MBO per well. Payout occurs within six months resulting in a ROI of 7.15. An economic summary is attached.


Dwight A. Ingram, et al holds a total of 6,073 net and gross acres in the project area, all of which are State of Utah, School and Institutional Trust Lands. A Net Revenue Interest of 81.5% will be delivered on the leases. An area of of Mutual Interest will be determined for the individual prospect areas. Negotiations for additional prospect acreage either by drilling option or farmout are in progress.

Lease Schedule

Legal descriptions, expiration dates, acreage and lease numbers can be found here.

Acoma Prospect

The proposed location on the Acoma Prospect, SWSW-5-T40S-R22E, will test a northeast trending, elongate closure as defined by subsurface well data. This feature covers an area about 1 mile long by I/2 miles wide Total structural relief across the feature is 75-100'.

Coincident with the mapped structural feature is a thick algal mound developed in the Lower Ismay. The mound is identified on logs in the British-American Oil No. B-1 Government-Norwood. The mound can be identified directly by the clean gamma-ray log curve response and associated sonic log porosity. Drape of the Hovenweep Shale occurs over the mound and is identified in cross-section. The proposed location is an updip offset to this well drilled to a total depth of 5850' in October 1963. A drillstem test of the Lower Ismay from 5630-5674' flowed gas to surface in 15 minutes, gauged at 25 MCFGPD. Pipe recovery was 30' HGCM, and 360' free OIL. Flow pressures during the test ranged from 62-166#, with shut-in pressures recorded at 2134-2063#. No water was recovered during the test.

Sonic log calculated porosities in the Lower Ismay in the No. B-1 Government-Norwood range from 2-10%, typical of productive algal mounds in the Bluff Bench Area. Archie calculated water saturations are as low as 30% over the drillstem test interval.

Laguna Prospect

The proposed location, SWNE-13-T40S-R21E is an updip offset to the Humble Oil and Refining No. 12 Bluff Bench, located SESE-12-T40S-R21E. Mapped closure and Lower Ismay algal builup covers about 600 acres. Net pay potential at this proposed location could reach more than 50' in three zones. The well pumped 47 BO + 40 BWPD from Ismay and Desert Creek perforations at 5381-5410' and 5660-5676'. This is one of the few wells in the area to have tested oil from both the Upper and Lower Ismay and from the Desert Creek. Perforations at 5381-5389' and 5398-5410' in the Upper Ismay recovered 58 BO + 38 BW in a 10 hour pump test. The Lower Ismay swabbed 30 BO + 130 BW from 5507-5514'. Porosity development in the Lower Ismay reaches 26'. The Desert Creek swabbed 46.5 BO + 3.5 BW in 24 hours from perforations at 5660-5666' and 5670-5676'.

Tecolote Prospect

The proposed location,SWNE-22-T40S-R22E, will test a thick Lower Ismay section identified on the sonic log in the Colorado Oil, Bluff Bench No. 1, SESW-22-T40S-R22E, from log depths between 5430-5490'. The interval was not tested. A core from 5352-5389' recovered 37' light gray tight limestone and 9' of brown argillaceous limestone with abundant black chert from the Upper Ismay. This core interval missed the Lower Ismay target zone by more than 50'. The well was plugged and abandoned untested in December 1964. The thick Lower Ismay zone correlates to the Ladd Petroleum, No. 23-32 Federal, SWNE-23-T40S-R22E, which pumped 78 BO + 94 BW + 20 MCFGPD from perforations at 5438-46' in May 1981. The interval from 5420-68 drillstem tested 2542' GIDP, 124' oil, 124 G&MCO, 555' G&OCM, 62' GCW&M, and 2043'GCW. Initial and Final flow pressures ranged from 413-1092# and 1118-1786# respectively. Shut-in pressures reached 2041 and 2028#. Cumulative production reached 6282 BO and the well was converted to a salt water disposal facility. This well appears to be near the oil-water contact for the Lower Ismay. The proposed location is mapped 100' high to the No. 23-32 Federal. Areally, the algal mound is almost 2 miles long by 3/4th's miles wide and is draped over a northeast trending closure containg 50-75' relief.


Algal mounds in the southern Paradox Basin have historically been important oil and gas exploratory targets. The above geologic analysis indicates that the oil and gas potential of the prospect area has been ineffectively exploited by previous operators. Numerous shows, multi-pay objectives, firm oil prices, and advances in drilling and completion technologies make the area an attractive exploratory play.

Full Report

An extensive report including graphs, Geologic Models and maps are available to interested parties.



Click Baxter to see - Baxter Ranch - San Joaquin Basin, Kings County, California  

Click Bluff Bench to see - Southern Paradox Basin - Bluff Bench - Aneth Area, San Juan County, Utah

Click Madden to see - Philp - Knapp Lease Madden Unit, Fremont County, Wyoming

Click Owl Creek to see - Owl Creek Thrust Trend - Wind River Basin, Fremont County, Wyoming






Dwight Ingram
Oil and Gas Specialist
Worldwide Consultant
32 years experience
Based in Denver, Colorado


Colorado: 303-726-5663
Florida: 904-310-9495



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