The Development and Evaluation of a Field Method for In-Situ Stress Determination Using Hydraulic Fracturing.

摘要

The Deep Stress Probe, a special field tool,has been developed for use in determining in-situ stresses at great depth in rock masses. The tool,adapted from oil well logging equipment,features orientation and downhole pressure recording components and needs only one lowering for each complete measurement at a certain horizon. A Laboratory technique was developed to control fracture propagation in laboratory tests simulating practical hydraulic fracturing situations. These studies reveal that permeability may increase dramatically prior to macroscopic fracture in hydraulic fracturing. This is very significant and allows a better understanding of the factors affecting the breakdown pressure (rate of loading,viscosity of fracturing fluid).