The Evaluation Of Hydraulic Fracturing Fractures Complexity By Using Fracturing Pressure Curve

Since the shale gas revolution in North America,fracturing technology has become a key technology for the development of unconventional oil and gas fields.At present,the volume fracturing technology is used in various vertical or horizontal wells to produce complex fractures;However,in the same field,sometimes single well production have great difference by using same technology.If there is a relatively more accurate way to evaluate the fracture complexity,it can help us both in fracturing effect evaluation,optimizing the fracturing process,reducing the cost,and increasing the production.By investigating and studying the domestic and foreign fracturing effect evaluation methods,it was found that the widely used diagnosis of fracture complexity is microseismic monitoring method.This method is relatively accurate,but because the cost is high,only few wells use this method.At present,fracturing pressure data is most directly available from the construction site and contains a lot of information.This paper analyzes the pressure fluctuations caused by the intermittent expansion of fractures during the fracturing process,and the different pressure drop rate caused by the sequence of fracture in different levels during the closing process.The idea of using the pressure characteristics of the construction pressure curve and the characterization of the fractures closure on the G-function to evaluate the fracture complexity is proposed,and improved models of net pressure and G-function are established.The fracture complexity evaluation methods based on two types of curve was proposed.These methods were applied to 28 wells in two oil fields,and the applicability of the method was verified by comparison with microseismic and production.These methods are suitable for evaluating fracture network,and they are simple and practical,so they are easy for promotion.