Study On Transient Fluid Flow Of Fractured Horizontal Well In Tight Oil Reservoir

Nowadays,with the rapid increase in demand for oil and gas resources,development emphasis expand to unconventional oil and gas resources.And fractured horizontal well technology gradually become the research focus.However,the research on flow rules is still not comprehensive.And one of the challenges is that how to describe pressure system forming mechanism and establish a reasonable model to show the pressure distribution and output during the tight oil development process.In order to solve this problem,on the basis of describing pressure system forming mechanism legitimately,this paper considers the influence of natural fractures,artificial fractures and non-Darcy flow pattern,divided the reservoir into five parts by using the original thinking of division model.Then we build the filtration equation for each part respectively,and combine the five regions into a whole part with pressure conditions on the boundary.In this way,we can establish a reasonable model about pressure distribution and output.Furthermore,distribution rules of effective use pressure system can be obtained.Three parameters are defined as effective use factor,range of effective use and degree of effective use.They are used to realize quantitative evaluation about effective use pressure system in tight oil reservoir in order to show development results.Then we study the factors which impact on the pressure and output curves,including wellbore storage coefficient,threshold pressure gradient,elastic storability ratio,cross flow coefficient,fracture factors,matrix factors and so on.We also use pressure superposition principle and numerical simulation method to achieve a simple multi-well pressure distribution.Finally,the field example analysis is provided.The research results prove that enhanced division model could simulate tight oil reservoir fracturing horizontal wells unstable seepage characteristics well,and the results are consistent with the case.By analytical method we get single well flow model and obtain sensitivity analysis results.Numerical simulation could make up for division model’s shortcoming.This could provide foundation for realizing parameters optimization in the development of tight oil reservoir.