The goal of this research is to develop brine compositions that increase oil recovery in the Goldsmith-Landreth San Andres Unit (GLSAU) [West Texas] and conduct several single-well and one multi-well pilot to test the technology.

University of Texas at Austin - Austin, TX 78759
Kinder Morgan CO2 Company, LP - Odessa, TX 79761

This R&D effort is designed to inject water with a composition engineered to improve oil recovery from the carbonate matrix in fractured reservoirs. Carbonate reservoirs tend to be oil-wet/mixed-wet due to positively charged carbonate mineral surfaces and negatively charged acidic/asphaltic components in oil. Many carbonate reservoirs are also highly fractured. Water injection is generally not effective in fractured oil-wet reservoirs because water does not imbibe into the matrix. The water composition can be engineered with ionic modification, surfactants, and nanoparticles which can change the wettability of carbonate rocks towards more water-wet conditions under which water can imbibe into the matrix and displace oil into the fractures. The engineered water can also lower interfacial tension and minimize capillary forces so that gravitation forces influence oil recovery from the matrix. Specifically, this effort aims to develop brine compositions that would increase oil recovery in the Goldsmith-Landreth San Andres Unit (GLSAU) [West Texas] and to conduct several single-well pilots and one multi-well pilot to test the technology.

This technology, if successful, can improve oil recovery from carbonates reservoirs. The learnings from the field tests will be used to develop a full field implementation plan for the Goldsmith-Landreth San Andres Unit (GLSAU) in West Texas and define engineering criteria to apply this process economically in carbonate reservoirs more broadly. There are many other carbonate reservoirs in West Texas with a large volume of conventional remaining oil. Yates alone has an Original Oil in Place of three (3) billion barrels. Beyond the U.S., successful demonstration of this technology could also improve recovery from other giant fractured carbonate reservoirs, e.g., Cantarell, Ku-Maloob-Zaap in Mexico; Tengiz in Kazakhstan. In general, development of improved oil recovery techniques from fractured carbonates has the potential to unlock five (5) billion barrels of oil in West Texas and 100 billion barrels world-wide.

• Brine composition has been optimized
• Four chemicals have been identified that can recover oil from bypassed regions
• Developed dolomite-micromodels
• Developed geostatistical reservoir characterization
• Design of Single well Pilot Tests were completed, and two wells have been identified for single well tests
• One well-pair and two well patterns have been identified for multi-well tests
• The pattern around well 251A was selected for the inter-well pilot test, has been worked over for injection and Tracer injection has started. A small slug of surfactant has been injected for characterization. Weak acids help wettability alteration by surfactants on carbonate rocks. Corefloods show that the acid-surfactant mixtures recover about 20% original oil in place (OOIP) in less than 2 PV. Microbially-induced calcite precipitation can be used to improve sweep efficiency.

Single-well Injection Soak Produce (ISP) tests are going well in the field. Kinder Morgan is happy with improvement of 2-5-fold oil rate increase. All eight ISP well tests have been completed. Phase 1 with surfactant Stepan Cetyl Trimethyl Ammonium Chloride (CETAC) performed better than Phase 2 with surfactant BASF Aspiro. CETAC is selected for the inter-well pilot test. It is being worked over for injection. The injection will start in the next three months. A well pattern is also being identified in the Yates field (near Goldsmith field). This pilot would help the goal of Task 7 to define the applicability of this technology.

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NETL — Anthony Zammerilli (anthony.zammerilli@netl.doe.gov or 304-285-4641)
University of Texas at Austin — Dr. Kishore Mohanty (kishore.mohanty@engr.utexas.edu or 512-471-3077)