ABSTRACT
Columbia Natural Resources, Inc. and Columbia Gas System Service Corporation, subsidiaries of the Columbia Gas System, and the United States Department of Energy (DOE) have successfully drilled and completed a horizontal well in the Devonian Shale in Martin County, Kentucky. The objective of this co-funded project is to assess the effectiveness and economic feasibility of applying horizontal drilling and stimulation techniques to enhance the production of natural gas from the Devonian Shale. Columbia's well is one of three wells in a DOE program called "Horizontal Wells in the Devonian Shale."
Drilling began June 1, 1990 and ended July 7, 1990. The well contains a three-part profile, a conventional vertical section, an angle building or curved section and finally the horizontal section.
The well reached a measured depth (MD) of 6,263 feet, 3,754 feet true vertical depth (TVD) and a horizontal displacement of 2,872 feet was achieved in the desired direction, N12°W. Both air and foam were used as drilling fluids. The vertical section, tangent section between the curves and the horizontal sections of the well, were drilled using conventional rotary drilling methods. Downhole motors were used to build angle in the curved sections.
Thirty-five gas shows were detected by the mud logger while drilling; measured flow rates exceeded 1 million cubic feet per day (MMcfd) at TD.
Mud and geophysical log information were used to establish discrete completion zones. A 5-1/2″ production string equipped with five Payzone Packers and FO Completion Tool established six completion zones: an openhole/slotted liner section at the bottom; three zones isolated by the external packers with access to the formation through sliding sleeve FO completion tools; and, two zones which were cemented.
Overall, this application of horizontal drilling has proven that additional reserves can be developed in the Devonian Shale by its application. The current economics could be greatly improved by developing additional technology.
