Determination of rock mechanics parameters by pressure of surface fracturing treatment

The rock mechanics parameters, such as Yang's modulus and Poisson's ratio, are determined on the basis of surface fracturing treatment pressure and instantaneous shut-in pressure during PAD stage. The first step is to calculate hole bottom pressure. Then the fracture propagation model is determined based on the curve of hole bottom pressure. In order to simplify the problem, PKN model and KGD model are utilized, and different equations are deduced for different fracture models. In essences, the relation curve of Yang's modulus and surface treatment pressure is determined based on the fact that the fracture width is not only related to Yang's modulus but also to net pressure within a fracture. The Poisson's ratio curve is also calculated out based on the curve of minimal horizontal stress which may be obtained by other reliable methods. Verified by another reliable technique, the presented new method is reliable and simplified and can be put into field applications conveniently. It can also be used to perform real time analysis as well as post-fracturing analysis.