Comparison of Hydraulic-Fracture Orientation Techniques

Abstract

Summary Knowledge of the orientation of hydraulic fractures can be important in determining optimum well locations in recovery from tight gas sands, waterflooding, and EOR. The diagnostic technology used to determine fracture orientation in single wells has matured during the last few years so that reliable field-proven techniques exist. Five fracture-orientation techniques have been investigated extensively in multiple wells and in several fields in east Texas and Alaska for well depths up to 12,000 ft [3600 m]. The techniques reviewed include active fracture mapping with tiltmeter arrays and a triaxial borehole seismic (TABS) tool. The active fracturing techniques are compared with the predictive techniques of stress relief, thermal expansion, and sonic velocity measurements on oriented sandstone cores. Sufficient field tests have been performed to evaluate the reliability and accuracy of the data, and the theory by which the data are interpreted. All the field and laboratory techniques investigated proved to be reliable and provided good agreement between four or five independent tests in the same wells and zones. Accuracy of the various field tests varied from 5 to 20° [0.09 to 0.35 rad], and methods for improving this accuracy are reviewed.