Texas Panhandle Granite Wash Formation: Horizontal Development Solutions

摘要

The Granite Wash formation in the Texas Panhandle is an active horizontal drilling trend where high initial gas rates combined with rich condensate yields create a rewarding investment opportunity for operators. The Granite Wash formation has been a drilling target for over 30 years but development accelerated rapidly after November 2004 when 20-acre downspacing was approved in the Buffalo Wallow field. In the years 2004-2008, vertical infill development was actively pursued with operators using an “assembly line” methodology that concentrated on cost reduction to achieve economic success. When soft gas prices made vertical wells economically challenging, operators turned to horizontal wells to improve the trend’s economics. Previous papers [Edwards (2010), Ingram (2006)] have explored optimizing completion technology in the Granite Wash so this paper’s objective is to find solutions to questions about initial production, rate decline, and liquid yields by examining the reservoir and fluid properties. The paper uses techniques developed for generalized tight gas sand reservoirs and applies Granite Wash formation data to create focused solutions. The data presented show the horizontal wells’ high initial rates can be correlated to the offset vertical well performance and the initial production declines are defined by linear flow. In addition, a technique for optimizing the number of completion stages is presented and the condensate yields are explained using an Equation of State (EoS).