Research On The Methods Of Fracturing Pressure Analysis

With the development of fracturing technology, more and more attention has been paid to the fracturing pressure analysis technique. The parameters obtained by the analysis of fracturing pressure can be used to analyze and assess fracturing quality scientifically and reasonably, and improve the effect of fracturing.Based on investigating literatures concerned with fracturing pressure analysis, the analyzing methods were further developed and improved in the paper. The analysis of pressure in the whole course of fracturing, including injection and pressure decline after pumping-off, was involved. Using the injection pressure analysis methods founded in this paper, fracture models were distinguished, fracture geometric parameters were acquired, and correlation functions between bottomhole pressure and rock mechanics parameters were established. In view of pressure analysis during the fracture closing, correlated formula were derived, fracture geometry model and interpreting methods were modified and improved. And fracture length, width, leakoff coefficient and efficiency of fracturing fluid, closure time were gained by analysis. Aimed at screen-out fracturing, a new leakoff model and interpreting theory were presented, and influential factors of leakoff coefficient were analyzed. Pressure behavior after closure was analyzed and described, parameters such as fracture length, spurt loss coefficient and reservoir permeability were estimated, which can validate the correctness of the analysis before closure very well. And a new method to figure out the closure pressure from the pressure decline data was founded. Finally, on the base of theory study, fracturing pressure analysis software has been developed with Visual Basic language in this paper, and using it parametric analysis and field cases study were carried out. It is shown that some useful information about reservoir, fracture geometry and leakoff behavior of fracturing fluid can be gained using the analysis models and interpreting methods referred to in the paper, and the reliability and applicability of this software is confirmed at the same time.