Paradox Basin Project Description

Increased oil production and reserves utilizing secondary/tertiary recovery techniques on small reservoirs in the Paradox Basin, Utah

Utah Geological Survey (UGS), Salt Lake City, Utah 84109
Principal Investigator: M. Lee Allison, UGS
Phone: (801) 537-3300; fax: (801) 537-3400
Contract No. DE-FC22-95BC14988

Objectives and Project Description

The primary objective of this project is to enhance domestic petroleum production by demonstration and technology transfer of an advanced oil recovery technology in the Paradox basin, southeastern Utah. Over 400 million bbls of oil have been produced from shallow-shelf carbonate reservoirs in the Pennsylvanian Paradox Formation in the Paradox basin of Utah, Colorado, and Arizona. With the exception of the giant Greater Aneth field, 100 plus oil fields in the basin typically contain 2 to 10 million bbls of original-oil-in-place. Only 15 to 20 percent of that oil is recoverable during primary production. To date, none of these small fields have been the site of secondary/tertiary recovery techniques used in large carbonate reservoirs and are, therefore, also at high risk of premature abandonment. Most of these fields are characterized by extremely high initial production rates followed by a very short production life (primary) and hence early abandonment. At least 200 million bbls of oil is at risk of being left behind in these small fields because of inefficient recovery practices and undrained heterogeneous reservoirs.

A two phase, multidisciplinary approach is being used to increase production and reserves from the shallow-shelf carbonate reservoirs in the Paradox basin. Phase I is the geological and reservoir characterization of five diversified small fields within the Navajo Nation with the best candidate field to be targeted for the pilot demonstration project.

Phase II will be a demonstration project on the field selected from the characterization study using the secondary/tertiary recovery techniques (CO2 or waterflood) identified as having the greatest potential for increased well productivity and ultimate recovery.

Project Performance Facts

The Paradox basin project consists of $2,734,501 of non-federal cost sharing, which is 54 percent of the total project cost. The project is currently within budget with approximately $4,400,000 remaining. Most project tasks are on schedule. However, the UGS has requested a no-cost extension in order to conduct an additional, second reservoir simulation which we believe will allow a more useful and complete evaluation. The project is meeting original performance expectations in this, year one of Phase I.

Participating Organizations

The following organizations are conducting work on the project: Utah Geological Survey* (prime contractor), Harken Southwest Corporation*, Utah Office of Energy and Resource Planning, Eby Petrography and Consulting Inc., and REGA Inc. (*indicates contribution to cost sharing). Data and guidance is being provided by Bligh Petroleum, Inc., Mobil Oil Corporation, and the Navajo Nation.

The Federal Government’s Engagement in this R&D

Most of shallow-shelf carbonate reservoirs are discovered and operated by small, independent oil companies that have no funds or staff to conduct R&D. Drilling budgets and operating costs are dependent on the price of oil. Small fluctuations (decreases) in oil prices can cause fields to become uneconomic and abandoned. For many operators, the cost of a secondary recovery project may be equal to a significant part of their net worth or their total investment in the fields. The technical and economic risk is too high for most operators to consider. However, if the technology can be shown to work in nearby fields, many of the operators tell us they would be eager to employ it themselves.

Federal and State governments have an economic interest in seeing increased production in these fields. Both receive direct revenues from mineral interests, royalties, and taxes. Both receive indirect benefit from increased economic activity. Although government is accepting some of the risk in this demonstration project, it will benefit proportionately more than any single operator because the cumulative return on an extra 200 million bbls of oil production will be enormous to local, state, and federal coffers. We envision this project as a prudent investment by government in maximizing return on the resources that government manages and regulates on behalf of the citizens of Utah and the U.S. Both the Federal and State governments have had an implicit partnership with oil producers since the time leases were issued or taxes levied. The DOE Oil Class Program and this project specifically, recognize that long term partnership, and seek to enhance production to mutual benefit.

Specific R&D Products/Accomplishments

The public technical and business benefits from this project will: (1) increase recoverable reserves by identifying untapped compartments created by reservoir heterogeneity, (2) increase deliverability through a waterflood or CO2 flood which exploits the reservoir along optimal fluid-flow paths, (3) identify reservoir trends for field extension drilling and stimulate exploration in Paradox basin fairways, (4) cause technology to be used in other identified basins with similar types of reservoirs, (5) prevent premature abandonment of numerous small fields, (6) reduce development costs by more closely delineating minimum field size and other parameters necessary to a successful flood, (7) allow limited energy investment dollars to be used more productively, and (8) increase royalty income to the Navajo Nation, Federal, State, and local governments, and fee owners. Through proper geological and engineering evaluation of the reservoirs, production may be increased by 175 percent (or an additional 2.1 million bbls per field) through the application of selected secondary/tertiary recovery projects.

Secondary recovery involving CO2 is very successful in the giant Greater Aneth field in the basin but differences in geology and the economics of scale have prevented operators from trying something similar on small fields. Operators are eager to try to replicate the success of the Greater Aneth field if they believe they have a reasonable chance of success. This demonstration project is intended to give them the insight to determine if they can go forward.

Expected R&D Products and Timetables

Phase I will be completed in the Fall of 1996. At that time we will determine whether the small field geology is conducive to a CO2 or waterflood and what the expected reservoir response will be. Initial results of Phase II, the field demonstration, will start by early 1997 and give a good indication of practicality of secondary recovery on small reservoirs. By the end of 1997, adjacent operators will be able to determine whether they should initiate projects of their own, even though longer term monitoring and evaluation will continue for an additional two years.