Analyzing Drawdown Pressure Curve After Hydraulic Fracturing

Hydraulic fracturing is very important in sides of enhancing oil recovery percent and oil off take very day. Although the technology of hydraulic fracturing becomes mature gradually, the construction effect of fracturing isn't evaluated by a kind of measure that is intuitionistic, simple, exact at the present time. Nolte founded two-dimensional fracture analysis model and analyzed drawdown pressure curve after hydraulic fracturing by use of the model. Hypothetic conditions of two-dimensional fracture analysis model have some differences with actual conditions, it can't exactly reflect geometry characters of fracture and parameters of fracture. Afterward three-dimensional fracture analysis model appears, but it has too much calculate-workload by use of three-dimensional fracture analysis model, under allowable conditions it can be predigested to pseudo three-dimensional fracture model in order to avoid the circs. The first, the thesis launches on analysis about the basal principle of hydraulic fracturing, thinks that pressure is basal data in the process of fracturing, working pressure reflects formation-condition, further more drawdown pressure curve reflects bom physical characters of reservoir, so it is reasonable that parameters of fracture are acquired by drawdown pressure curve; the second , the thesis introduces two kinds of fracture models including PKN and KGD ,which can estimate filtration coefficient, fracture length, fracture width and closure time; at the last, the thesis analyzes drawdown pressure curve by use of three-dimensional fracture model and makes software to calculate fracture parameters, which compare with results that are calculated by two-dimensional fracture in order to realize differences between two models and validate that it is feasible that fracture parameters can be obtained by analyzing drawdown curve.