Abstract

The Yates Formation gas is an unconventional resource play, the proverbial “sleeping giant”, covering a large portion of Gaines, Andrews, Terry and Yoakum Counties in west Texas. Comprised of aeolian sands deposited within an evaporate sequence, the detailed lithology, petrophysical properties and aerial productivity are poorly understood. To date, over 311 BCF of high nitrogen Yates gas has been produced from these four counties. Proration units range in size from 40 to 640 acres with individual gas well accumulations of up to 7 BCF. Remaining recoverable gas could be three or four times current cumulative production emphasizing the importance of this widely misunderstood reservoir.

Historically, in many areas of the Permian Basin, Yates gas has been considered ‘trash gas” because of its high nitrogen content. However, recent technology coupled with operational efficiency and higher gas prices have made exploration and development of Yates gas economically attractive. Two nitrogen rejection plants have been constructed in Gaines County, with a combined inlet stream capability of 21,000 MCFPD, producing highly valuable pipeline quality gas and liquids. Nitrogen content of the Yates gas is variable and ranges up to 33% in the subject area with relatively low btu (960) content. However, once nitrogen is extracted, btu content of the remaining gas increases to 1200 resulting in significant liquids value.

Published geological evaluations of the Yates formation are scarce within this four county area. Field and regional studies are currently underway to better understand Yates depositional, lithological, petrophysical properties and the economic importance of this resource play.