Operations

Summary of Combined Miscible Drive Process

Legacy Energy (a wholly owned subsidiary of NiMin Energy Corp.) has created and implemented an enhanced oil recovery process at the Pleito Creek oil field, Kern County, California. The process combines the effects of gravity drainage with a new wet combustion technique, where steam and carbon dioxide (CO2) are generated in-situ. In this process there is no release of "new" emissions to the atmosphere. Legacy Energy was awarded a patent from the U.S. Patent and Trademark Office for this process in December 2010 which is referred to as Combined Miscible Drive (CMD).

Oxygen-enriched air and water is injected as foam into the top of the reservoir. A small amount of oil will be continuously oxidized resulting in production of carbon dioxide rich flue gas and heat which converts nearby water to steam. The carbon dioxide gas absorbs into the oil reducing its viscosity, significantly increasing its mobility and up-grading its API gravity. The steam further reduces oil viscosity and drives the CO2 enhanced oil column down structure toward the producing wells. Horizontal production wells were drilled down structure of the flood front where they capture up-graded oil from the near-miscible carbon dioxide displacement front and cold oil being pushed ahead of the flood front. The diagram on the right graphically illustrates a cross section through the oil reservoir below the surface facilities. In map view, (right) the CMD injector is surrounded by the horizontal wells at the geologic crest of the oil field.

Legacy has identified numerous oil fields in the United States which have reservoirs it believes to be high quality candidates for the CMD process. Reservoirs which are considered candidates for the CMD process have similar characteristics to reservoirs that are targeted for CO2 or steam floods. The advantage with the CMD process, however, is that it can be used in reservoirs that are too deep to be steam flooded with conventional technology and in fields which are relatively distant from a source of CO2. Legacy plans to exploit the technical advantages of the CMD process to acquire underdeveloped assets. Since oil recovery factors are expected to be as high as sixty percent, we are very excited about the CMD process.