Print this pageAbstract: Mesaverde Group Sandstone Reservoir Characteristics, San Juan Basin, New Mexico and Colorado
Robert G. Raynolds, Ira Pasternack
The Upper Cretaceous Mesaverde Group of the San Juan basin contains multiple tight gas sandstone reservoirs that have been developed by about 5400 wells. Mesaverde production to date exceeds 7.4 TCFG and 21 MMB0.
The Mesaverde is a regressive-transgressive, northeastward prograding wedge that thins from 1000 feet to 400 feet across its productive limits. It is comprised of three formations, in ascending order: the seaward stepping near shore sandstones of the Point Lookout formation; the coastal plain assemblage of the Menefee formation; and the landward stepping near shore sandstones of the Cliff House formation.
Production occurs in a northwest-southeast trending belt that is 75 mi long and 35 mi wide controlled by the development of one or more of the near shore sandstones. The stacking patterns and geometries of the regressive phase sandstones differ from those of the transgressive phase because of the interaction of subsidence rates, sediment supply, and eustatic change. This architecture controls reservoir compartmentalization. Point Lookout sandstones tend to be thinner, shalier and have slightly poorer reservoir characteristics than the Cliff House sandstones.
Two dozen wells exhibit significantly better performance than average--as much as a tenfold improvement in rate profiles and reserve estimates. Multiple lines of evidence indicate that the anomalous production is a result of natural fracture induced permeability enhancement.
Water above gas, particularly well documented along the southwestern edge of the producing trend, suggests a basin centered gas accumulation.
AAPG Search and Discovery Article #90986©1994 AAPG Annual Convention, Denver, Colorado, June 12-15, 1994