Partitioned Model Of Volume-Fractured Horizontal Well In Tight Oil Reservoirs

The development of tight oil reservoirs is achieved in virtue of the horizontal well technology and the large scale hydraulic fracture measures.Revealing the seepage law of horizontal volume fracture wells,establishing the partition productivity prediction model of horizontal volume fracturing wells are extremely significant for accelerating the development of tight reservoirs as well as changing the national energy strategy.The paper establishes the partition productivity prediction model of tight oil reservoirs,based on the physical model of horizontal volume fracturing well.The fracturing area is double medium of fracture network which is coupled by artificial and natural cracks and matrix.The outside area is single medium,considering the effect of start-up pressure gradient and capillary force.The flow continuity is used to deduce the coupling mathematical model between reservoir and fracture as well as wellbore.The coupling model is dealt with fully implicit difference,and using N-R iteration to solve it.Making some stimulations to analysis the effect factors to horizontal volume fracture well productivity,such as the start-up pressure gradient,fracture clusters number,production pressure draw-down,fracture half length,fracture flow conductivity and fracture sections number.To sort the productivity influence factors based on the important degree by using multiple regression analysis method.We can get the conclusion that the start-up pressure gradient and half fracture length are the greatest influence factor on productivity.The application example of Lucaogou tight oil reservoir shows that the partition model can be used to predict the initial productivity of horizontal volume fracture well.Through the study of theoretical analysis and numerical stimulation,the productivity prediction model have a certain guiding significance to the effective development of tight oil reservoir.