Study On Rate Transient Analysis Of Fractured Horizontal Well In Tight Oil Reservoir

Nowadays,with the rapid increase in demand for oil and gas resourses,development emphasis expand to unconventional oil and gas resources.And fractured horizontal well technology gradually become the research focus.Because the development of ultratight oil and gas reservoirs is difficult and the formation conditions is complicated,development usually through multi-stage fractured horizontal well.Conventional reservoir engineering rate analysis method can not analyze rate of ultratight oil and gas reservoirs validly,so we need a new rate analysis method.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 rate transient analysis model and study the influence of geological parameter,fracture parameter and matrix parameter on the rate curve.According to rate transient analysis model,the method to dividing flow regions of ultratight oil and gas reservoirs is established.For different flow regions simplified rate analysis formula of corresponding form and established analysis equation.Then,dual porosity reservoir simplified to different kinds of geological models.At last,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.We can use the rate data directly to analysis and avoid multiple test impact on production.