Site selection, drilling, and completion of two horizontal wells in the Devonian Shales of West Virginia

Abstract

This report presents a summary of the geologic site selection studies, planning, drilling, completing, stimulating, and testing of two horizontal wells drilled in the Devonian Shales of the Appalachian Basin in West Virginia. Each horizontal well was designed and managed by BDM as the prime contractor to the Department of Energy. The first well was drilled with industry partner Cabot Oil and Gas Corporation in Putnam County, West Virginia. The second well was drilled with Consolidated Natural Gas Company in Calhoun County, West Virginia. This report summarizes four reports prepared by BDM which detail the site selection rationale and the drilling and completion operations of each weil. Each horizontal well is currently producing commercial quantities of hydrocarbons. The successful application of horizontal well technology represent continued development of the technology for application to tight and unconventional natural gas resources of the United States. Continued technology development is expected to ultimately result in commercial horizontal well drilling activity by industry in the Appalachian Basin. ix 1.0 EXECUTIVESUMMARY This report summarizes the geologic studies, site selection, drilling, logging, completion, and well _testing of two horizontal wells t drilled in the gas-bearing Devonian Shale interval in the Appalachian Basin. Detailed technical information concerning each of the two wells reviewed in this volume will be found in the technical report for each weil. Cash flow analyses were undertaken for each horizontal well using the well-specific cost and production information available through the end of January 1992. These results, detailed in this volume, show that a horizontal well is economic over a wide range of economic conditions if: (1) The well cost can be controlled to between $500,000 and $700,000 and (2) If the well is likely to produce at least 140 Mcf/day over the first year of operations, depending on the price of natural gas.

Life Cycle Water Consumption for Shale Gas and Conventional Natural Gas

“…Water is used during the well construction stage in drilling fluids, for cementing the casing in place, and for hydraulically fracturing the well in the case of shale gas. Well designs developed to estimate water requirements for drilling and cementing were based on designs for the 4H, 5H, and 6H Carol Baker wells for shale gas wells and upon a typical casing program found in the Mississippi Smackover Trend, for the conventional nonassociated onshore natural gas well (see SI Table S1). − Horizontal wells are drilled vertically to a point about 300 m (900 ft) above the shale formation, at which point the drilling follows a large-radius turn of approximately 90 degrees so that the well runs laterally (horizontally) through the shale for up to 2000 m (6000 ft) or more (see SI Figure S3). This long lateral reach enables a horizontal well to access more of the shale resource than a vertical well would be able to.…”

Life-cycle analysis of shale gas and natural gas.

“…These assumptions are similar to those reported by Tester et al (2006), EPA (2004a), andRadback Energy (2009). By assuming that the drill rig operates 24 hours per day and then using an average number of days drilled from Overbey et al (1992) and extrapolating to the various plays according to depth, the total diesel fuel required for drilling can be determined. Although diesel fuel requirements for on-site activities and transportation burdens for diesel and water were included in the inventory, the transportation burdens of materials (e.g.…”