Institutions:
NEW MEXICO INST MIN & TECHNOL,NEW MEXICO BUR MINES & MINERAL RESOURCES,SOCORRO,NM 87801
Abstract:
Carbonate reservoirs in the Cisco and Canyon (Upper Pennsylvanian) and lower Wolfcampian (Permian) sections in the Permian Basin of southeast New Mexico, U.S.A. are significant reservoirs for oil and gas. The approximately 400 fields that have produced from these reservoirs have yielded a cumulative production of 490 million bbls oil (MMBO; 78 million m(3)) and 3.2 trillion ft(3) (91 billion m(3)) gas, 12% of the oil and 16% of the gas produced in southeast New Mexico. Sixteen of these fields have been identified that were underdeveloped at some stage in their history. Cumulative production ranges from Milnesand West (0.210 MMBO; 0.033 million m(3)) to Dagger Draw (31 MMBO; 4.9 million m(3)). Although initially underdeveloped subsequent redevelopment of these 16 fields added significantly to reserves and production. Statistical analysis of production decline curves was used to estimate reserves developed during initial drilling of these fields and during subsequent phases of redevelopment For the 16 fields studied, redevelopment accounted for a total of 65% of developed reserves. Redevelopment accounted for more than 90% of total reserves at Dagger Draw and 99% at Baum. Redevelopment in these fields was generally in undrilled portions of the fields, and not in bypassed pay zones. The fields are formed by stratigraphic traps but were initially thought to be structural traps and were developed on structural culminations. Because initial development was based on the premise of structural entrapment, the majority of reserves in these fields remained unproduced until redevelopment. Redevelopment generally resulted in a fivefold to tenfold increase in numbers of producing wells and productive acreage. Because 84% Of Upper Pennsylvanian and lower Wolfcampian fields have less than 10 producing wells and 57% have less than three producing wells, it would appear that significant reserves may remain undeveloped in most existing fields. For those fields that have been developed only on structures, additional study of carbonate facies and environments is needed to fully delineate the reservoirs and identify full potential.