Theoretical Study On Prediction Of Fracturing Yield In Horizontal Wells

Horizontal well multistage fracturing in low permeability reservoirs is more and more widely used. Production prediction of horizontal Wells after fracturing is an important basis for the decision of horizontal well fracturing, therefore scholars both at home and abroad do large number of research in this field. But the existing horizontal well fracturing production prediction model is mainly about after pseudo steady state.Meanwhile the late unstable seepage stage especially after the pressure wave pass to the boundary of unstable seepage research are little. Other production prediction method for multi-port fracturing and horizontal well production is less, in this paper, the horizontal well fracturing production prediction theory has carried on the thorough research. The main contents are as follows:1.According to the complex potential theory and potential superposition principle, the fracturing of horizontal wells is established after the pressure of single well productivity calculation mathematical model.The model considering in closed during the period of the establishment of the formation of unstable early, late instability, quasi stable seepage period, three different according to different characteristics of the three periods, respectively established the corresponding capacity calculation mathematical model, and through the numerical analysis method to identify each phase transition,This model considered the parameters including interferences between fractures, fracture asymmetry, azimuth of fractures, distances between fractures.2.Through the calculation of the model, calculated the three seepage phase transition time.By calculating the time point, analyzed the fracturing parameters effect on the capacity of each flow period, the final optimization results are obtained.3.The fracturing of multiple horizontal Wells productivity calculation model is established, by using the seepage mechanics basic knowledge and the method of well pattern shape factor, respectively established unstable and quasi stable seepage mathematical model in close formation.4.Using the mirror image method, fractured multi-well production problem is simplified to single well production problems, and through the single well fracturing parameters optimization, to get the optimal fracturing parameters of multiple wells production.In this paper, the horizontal well productivity prediction after fracturing theory model has carried on the systematic and thorough research, and the horizontal well fracturing late-unstable seepage research has certain innovation. Paper work for horizontal wells after fracturing fluid percolation mechanism has certain theory value and has a guiding significance for guidance of horizontal well fracturing parameters design.