Design Optimizaition And Performance Estimation Of Volume Fracturing Horizontal Well In Tight Oil Reservoir

Given the extremely low permeability of the tight oil reservoir,the recovery is relatively low through conventional technology and the development of horizontal well drilling and hydraulic fracturing has been the critical factor to exploit the tight oil reservoir effectively.In previous studies the horizontal well fractures distribute symmetry and homogeneously without consideration of heterogeneous formation and without consideration of the correlation of fracturing effectiveness and fracturing location selection.Therefore,it's necessary to estimate the formation fracability and to introduce the factor into the optimization of the fracturing design.Firstly,the essay analyzes various parameters' influence on fracability,such as brittleness index,fracture toughness,exhaustively,strain energy release rate,configuration of natural fractures and stress distribution.Then we utilize the well logging data to obtain the mechanical experiment,acquire the fracability finally and establish the calculation work flow.Furthermore,a variety of calculating methods are gotten and compared and the most reliable and effective method is screened,which synthesize the brittleness and energy consuming comprehensively.Based on this method,a typical well region is appraised and fracture locations of the design and real work material is made contrast,which indicate the profound significance of the fracability.Secondly,based on the distribution of the fracbility,the article optimizes the design of the fractures.As perceived that fracability plays an important role on the fracturing effectiveness,it should be considered seriously.The fracture conductivity varies positively with fracability,so the former can be deduced from the latter.In the next step,we chose the net present value as the target which based on the current flowing out and coming in and contrast the optimization system for the fracturing horizontal well with the help of commercial simulator and SPSA algorithm.As the results show that the space of fracture is straiter and the length is longer where the fracability is higher relatively and the performance of the optimizing well is better than that of fracture distributing evenly well.In the end,we utilize the fuzzy comprehensive estimation method and AHP to form the post-fracturing system for the horizontal well based on the two hierarchy index system including formation dimension,technology factor and production aspect.To embody the contrast of actual performance and optimization result,the actual-optical ratio is introduced into the model.Furthermore,the definitions of total fracture length and conductivity per fracture length are built to increase the objectivity and effectiveness.Implication on a typical well demonstrate that the performance is excellent which verifies the validity of the hypothesis to absorb the fracability into the well optimization.Based on the research,it's significant to take formation property and fracability into consideration in the optimization of the fracturing horizontal well.Moreover,our study can provide important instruction for the development of tight oil reservoir.