The Permian Basin is one of the top five resource plays in the United States and consists of a number of stacked pay zones. Two of these formations, the Wolfcamp shale and Bone Spring (Wolfbone), together deliver a pay zone thickness of 1,000 to 1,500 ft. They are made up of several different layers of organic rich shales intermingled with sandstone and siltstone. Horizontal completions in the shales are just beginning and have yet to be proven; however, operators are successfully exploiting the reserves through vertical wells.
While a mature exploration area, the completion of the thick shale intervals is a new target formation. To date, two vertical completion methods have been utilized to gain access to hydrocarbons: open hole multistage systems (OHMS) and the conventional cemented liner, "plug and perf" (CLPP) method. This paper compares 30-, 60-, and 90-day production results from 12 vertical wells in Reeves County, Texas completed with OHMS systems and 44 offset wells completed with the CLPP method. The system details, fracture methods used, as well as the cost and operational differences are discussed.
By comparing these two methods, this paper highlights OHMS as a long-term solution for operators completing vertical wells in stacked pay. The production, operation and cost comparisons of the two completion methods will provide theoretical and practical arguments to assist in designing a completion. The results of this study contribute to the technical conversation of how to economically produce a vertical well.