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Yeso Formation Along the Northwest Shelf, Southeast New Mexico, USA: Conventional or Unconventional Reservoir Development?


During the past decade development of the Yeso Formation along the Northwest Shelf of the Permian Basin in Southeast New Mexico has progressed rapidly. The Paddock and Blinebry members of the upper Yeso Formation are the targets for this development. In 2011 ConocoPhillips began to develop the Yeso on a small acreage position near Maljamar, New Mexico. To date more than 70 vertical wells have been drilled on that acreage with maximum production reaching more than 3500 BOEPD. With the recent decline in oil price, development by vertical wells has become less attractive and horizontal wells have become the focus for many operators. The Yeso Formation was deposited on a shallow carbonate ramp during the Early to Middle Permian (Leonardian) (Ruppel and Ward, 2013). The Paddock and Blinebry members are composed of anhydritic dolomite with interbedded siltstones and fine-grained sandstones. The best reservoir facies were developed along the high-energy ramp crest to platform margin and are composed of peloidal grainstones to packstones with minor amounts of ooilitic and fossiliferous grainstones. Historically, the conventional reservoirs of the ramp crest were identified and first drilled in the 1960's and are still under development today, particularly in Vacuum Field. Recent Yeso development, however, has focused on the inner to middle ramp deposits that are dominated by heavily bioturbated peloidal packstones and wackestones, with minor amounts of bioturbated to laminated mudstones. The inner to middle ramp deposits of the Yeso typically display poor reservoir quality when compared to the conventional reservoirs of the Permian Basin. The Paddock in the Maljamar area is a poor conventional reservoir with average porosity of 7.5% and permeability ranging from 0-350 md, while the Blinebry is a tight-carbonate unconventional reservoir (Bishop, 2014) with average porosity of 3% and permeability ranging from 0-15 md. Due to the paucity of rock data for the Yeso in the Maljamar area much of the geologic analysis has focused on petrophysical and geophysical studies. Seismic attribute and waveform analyses have been used to identify reservoir sweet spots. While petrophysical studies have focused on the identification and mapping of pay and development of a detailed stratigraphy. Engineering studies have focused on understanding production trends, type-curve development, and optimizing the completions techniques to maximize production from these tight reservoirs.