Study Of Productivity Simulation Of Volume Fracturing For Horizontal Wells In Tight Oil Reservoirs

The productivity on tight oil has been increased yearly,and it has become an important part of the unconventional oil and gas resources in China.However,there is still a problem of high production in the early stage and fast decline in the middle and late stage of the tight oil well.Therefore,analyzing and studying the factors affecting the production of tight oil wells after fracturing become necessary.This paper provides the research object of the tight reservoir volume after fracturing horizontal wells,with the partition modeling and a basis on the fractured horizontal wells three linear flow model,and in consideration of the influence of natural fracture existing in reservoir reconstruction and non-transformation zone and the uneven distribution characteristics of fractures,to respectively establish a dual media oil production model and double media fractal reservoir yield mathematical models.We use Laplace transform and Stehfest numerical inversion to solve the mathematical model and get the analytical solution of the model,and analyze the factors that affect the productivity and compare the accuracy of the two models further by MATLAB programming.The research results are as below:(1)The seepage characteristics of the tight oil horizontal well after SRV were analyzed,and the morphological characteristics of the network distribution after fracturing were reconstructed.(2)This paper provides a mathematical model for dual medium reservoir production considering the influence of natural fractures in reservoir and the analytical solution of the model by Laplasse transformation and numerical inversion,and establishes the yield double media fractal reservoir model based on the dual media reservoir production model and considering the transformation of non-uniform distribution characteristics of fracture network,fractal permeability and porosity fractal,and the analytical solution of the model by Laplasse transform and numerical inversion;(3)An example of a tight oil well in Changji oil field,Xinjiang,was carried out by using MATLAB programming program.A method of solving single well control boundary using Fetkovich decline curve method is also presented.(4)Analysis of the change effects of the number of fractures,fracture half length,dimensionless fracture conductivity,the Outer boundary length of reservoir,the storativity ratio inside and outside transformation zone and flow coefficient and other parameters on dual media reservoir yield calculation,and cross flow coefficient and storativity ratio,complex fracture index on double media fractal oil production.This paper has carried out a comprehensive research on production analysis of tight oil horizontal wells after volume fracturing,and has made some innovations in modeling and solving problems,which is of great significance for optimization design of fracturing parameters for tight oil wells.