Hydraulic Fracture Reorientation: Theory, Prediction, and Application

by
James R. Tague III, MSE

University of Texas at Austin, 1997
Supervisors: Jon E. Olson
A. Daniel Hill

Refracturing is commonly used to increase production and expand recoverable reserves of a producing well. Typical candidates for refracturing include wells in which the initial fracture failed to achieve desired properties, primarily fracture length and conductivity. Recently, attention has focused on a new application of refracturing - that of reorientation. Although the exact nature of reorientation is poorly understood, the general mechanism for reorientation appears to be pore pressure depletion in the formation surrounding the initial fracture. This pressure depletion is believed to change the in situ principal stress directions. Hence, any subsequent refracture treatment will create a new fracture plane and contact new, less depleted reservoir rock. Thus fracture reorientation may make it possible to reach unswept areas of the reservoir and increase the overall production of numerous producing fields.

This paper outlines the theory of fracture reorientation and investigates the potential impact on well economics. Using published examples of fracture orientation as a guide, reservoir simulations were performed demonstrating significant production increases for refractured wells experiencing fracture reorientation. Based on published theory, actual field studies, and the reservoir simulation results, a set of criteria are developed to identify prospective wells where refracturing treatments involving fracture reorientation can enhance and improve overall production.

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