Fractured Reservoir Fracturing Pressure Decline Analysis And Application

With the development of hydraulic fracturing technique, fracture diagnose and evaluation techniques after fracturing have been attached more and more importance.The corresponding measurement method and interpreting techniques after fracturing need to be developed and consummated. The existent pressure drawdown analysis technologies interpret nothing but low-permeability and isotrop reservoirs, instead of interpreting pressure decline analysis of anisotropic fractured reservoir where there are a lot of natural fracture . Based on atore human's investigation , this paper has developed and consummated the pressure decline analysis ans interpring technology of hydraulic fracturing, and formed new pressure drawdown analysis and interpretation method. This technology has overcome the insufficiency of traditional pressure drawdown analysis and interpretation technology. So it is true of the pressure decline analysis of the natural fracture developmental anisotropic fractured reservoir, and can interpret the effect of fracturing construction, which is great significative to fracturing design.This paper has, first, studied the impact on natural fracturing into fractured reservoir to leakoff coefficent, deducted the pressure drop equation of fractured reservoir, and deduced the computation model of fluid efficiency.Second, based on improving traditional G-function analysis method, this paper has redefined matching pressure,and adopted the method that mathematics and figure are integrated to count matching pressure, replacing labour curve matching method in traditional G-function analysis and advancing the precision and reliability of the curve matching. Thirdly,on the basis of these,this paper has deduced and founded leakoff coefficient model and spurt loss coefficient model, studied the rule of pressure changing before and after fracture closing and lodge the method of ascertaining closing of fracture.Lastly,through the anterior studies that have done, this paper has founded the pressure decline analysis models fitting fractured reservoir under the condition of back flow and compressibility of fracturing fluids, and established the software, thereby formed new pressure decline analysis and interpretation technology.With this technology, some parameters on fracturing and reservoir can be obtained, such as leakoff coefficent, spurt loss coefficient, matching pressure, shut-in pressure, closing time, fracturing extend time, fracture length, fracture width , fluid efficiency and so on. The method , models and software of this paper are reliable and applicable, which have been illustrated, can analyses and evaluate the workmanship of fracturing reasonably and direct fracturing design, which is of great moment to the development and application of the pressure decline analysis technologies on theory and practice.