The determination of induced fracture strike is an important factor in both the primary and secondary development of oil and primary and secondary development of oil and gas reservoirs. If a common strike can be substantiated for a field or area, ultimate recoveries can be increased through exploiting the reservoir on a development pattern that conforms to the induced fracture strike.
This paper is a practical discussion of the use of the Borehole Televiewer log in wells in the Appalachian basin to determine induced fracture strike. Log sections are presented and various applications of results are discussed. Two anomalous cases are also presented and discussed.
The importance of determining the strike of induced or natural fractures has been recognized for some time. Early work with the Lynes packer and more recent work with softer rubber packer and more recent work with softer rubber impression packers have provided information about the strike and configuration of both natural and induced fractures. However, the impression packer procedure is sometimes costly, time-consuming and the orientation procedure at times questionable. In 1968, an open-hole logging tool patented by Mobil was introduced to the industry to define fractures and give an accurate orientation in a simple logging operation. This tool has generally given good results in wells logged in the Appalachian basin, and the results have easily been interpreted.
More emphasis has been placed on the application of fracture orientation data to planning secondary recovery. However, if planning secondary recovery. However, if primary development wells are completed with a primary development wells are completed with a fracture treatment, secondary recovery potential with respect to fracture orientation must be considered from the start of initial field development.
One of the most significant field secondary recovery developments, based on indicated natural fracture strike, was the waterflood development of the Spraberry field in West Texas. Waterflood patterns were designed to conform to the natural major fracture system to maximize sweep efficiency. Several operators have installed secondary recovery project patterns to conform to the induced fracture strike, patterns to conform to the induced fracture strike, but very little is available in the literature as to how successful these efforts have been.
