Carbonate reservoirs of Upper Pennsylvanian and Lower Permian age are significant reservoirs for oil and gas in southeast New Mexico . The approximately 400 Upper Pennsylvanian and Lower Permian carbonate reservoirs have produced a cumulative 508 million bbls oil (MMBO) and 3.2 trillion ft3 gas (TCFG). This is 12 percent of the oil and 16 percent of the gas produced in southeast New Mexico.
Sixteen of these 400 fields have been identified as being underdeveloped at some stage in their history. At the beginning of 1998, these ranged in size from tiny Milnesand West with a cumulative production of 296 thousand bbls oil (MBO) to huge Dagger Draw with a cumulative production of 55 MMBO.
An underdeveloped field can be defined as an oil or gas field that was incompletely developed subsequent to initial field discovery. Underdeveloped fields typically produce minimal levels of oil and gas from only a few wells drilled in the period immediately following field discovery. One or more subsequent discrete phases of redevelopment several years, even decades, after field discovery reinvigorate production. These phases of redevelopment do not involve infill drilling nor do they involve secondary or tertiary recovery techniques. Rather, they are based upon drilling the same pay zone that was produced during initial development of the field but from proration units that remained undrilled during initial development. As such, they represent new oil that was unrecognized at the time of field discovery and initial development. For the 16 identified underdeveloped fields, redevelopment has accounted for 65% of developed reserves and initial development has accounted for only 35% of developed reserves (Table 1).
Cumulative oil production,
|Percent reserves from initial development||Percent reserves from 1st redevelopment||Percent reserves from 2nd redevelopment|