Design and Execution of Horizontal Wells in Gas Shales Using Borehole Images and Geochemical Data

Camron Miller, Rick Lewis, and Keith Bartenhagen
Schlumberger

Horizontal drilling is a key technology used worldwide in conventional and unconventional reservoirs to maximize and speed the recovery of hydrocarbons. Most conventional reservoirs within the United States have been exploited, and the focus is now on the development of unconventional plays. Organic shales, the hydrocarbon source for conventional reservoirs, have become a viable target resource. The poor reservoir characteristics of shales make them ideal candidates for horizontal drilling development. This paper will focus on new technologies and strategies for horizontal well placement within gas shales.
    These projects require interaction between geologists, engineers, and petrophysicists to develop a detailed and integrated approach to the design and execution of horizontal wells. Key reservoir parameters and evaluation packages have been established for gas shale deposits.
    Borehole images and geochemical data have become the standard evaluation technique for gas shales. Geochemical logs provide a gamma-ray-independent clay content and a matrix density that corrects for the complex lithology of shales. These data are used along with borehole images to identify shale layers with the optimal mineralogy for reservoir performance and drillability. Borehole images allow one to identify and define the orientation of bedding, drilling-induced and natural fractures, and faults. These data are used to determine the drilling azimuth and inclination angle for the horizontal well.
    These techniques have been successfully applied to many horizontal wells within the continental United States. Several examples will be presented. Sharing new technologies and strategies for horizontal well employment should allow operators to become more successful in these ventures.

AAPG Search and Discover Article #90065©2007 AAPG Southwest Section Meeting, Wichita Falls, Texas