Microcrack Model and Its Significance to Hydraulic Fracturing and Fracture Toughness Testing

摘要

A rock mechanics/fracture mechanics model is formulated that describes the probable character of the microcrack zone at a crack tip in rock. Knowledge of the crack tip process zone is an important step in the general understanding of fracture propagation in rock. In particular, it may prove useful in descriptions and models of hydraulic fracture propagation near formation interfaces. Such a microcrack model is also needed in order to understand rock fracture testing on the laboratory scale and to help establish guidelines for fracture toughness testing. Initial calculations and results with this model reveal several explanations for anomalous behavior in hydraulic fracturing and in fracture toughness testing. 3 figures. (ERA citation 05:019727)