Abstract

The Shattuck Member of the Queen Formation (Upper Permian, Guadalupian) is a prolific oil and gas producer in the Permian Basin of West Texas and southeastern New Mexico. It forms a regionally extensive reservoir covering more than 10,000 km² (4000 mi²) on the Northwest Shelf of southeastern New Mexico. The Shattuck was deposited during a lowstand in eustatic sea level and lies directly above a type 1 sequence boundary. Two major siliciclastic facies are present in the reservoir, one with mainly evaporite cements and the other with mainly dolomite cement. Calibration of well logs with core allowed the facies to be differentiated and mapped across the study area in southeastern New Mexico. Facies A consists mainly of siltstones and sandstones with evaporite cements. This facies was deposited in wadi and sabkha settings. The sandstones deposited in the wadis from north-south trending thicks on isopach maps. These thicks represent the fills of channels incised into the exposed shelf during a lowstand in eustatic sea level. The channel sandstones contain admixtures of eolian sediment and display horizontal and ripple laminae. The sabkha deposits in facies A are found immediately landward of the Artesia Vacuum trend along the shelf edge in the southern portion of the study area. These sandstones have an east-west orientation and display cryptalgal lamination. Facies B consists primarily of sandstones with mainly dolomite cement. This facies is found basinward of the Artesia Vacuum trend and, like the sabkha deposits in facies A, has an east-west orientation. The sandstones in facies B were deposited in fully marine settings.