致密油藏压裂水平井非稳态产能预测模型

考虑启动压力梯度和压敏效应影响下的基质—裂缝、裂缝—井筒的耦合流动，以椭圆渗流理论和叠加原理为基础，通过当量井径原理，建立了带有多条横向裂缝且裂缝间相互干扰的压裂水平井的非稳态产能预测模型，并分析了压裂水平井产量变化规律及各因素对产能的影响。实例计算结果表明，致密油藏压裂水平井初期产量高、递减快、高产期短，后期产量低、趋于平稳、稳产期长。启动压力梯度和应力敏感效应影响大，启动压力梯度、变形系数越大，压裂水平井单井产量越低。水平段长度越长、压裂缝条数越多、裂缝越长、导流能力越大，压裂水平井产量越高，但各自存在最优范围。

An Unstable Productivity Prediction Model for Fractured Horizontal Well in Tight Oil Reservoirs

In consideration of the matrix?crack and crack wellbore coupling flow under the threshold pressure gradient and the pressuresensitive effect, on the basis of elliptic seepage theory, superposition principle and equivalent wellbore radius model, an unsteady productivity prediction model for fractured horizontal well with arbitrary numbers of transverse fractures was developed considering mutual interference among fractures. Then the oil production decline rules of fractured horizontal well and the effects of various factors on its productivity were analyzed. The computational results from a case study show that such a well in tight oil reservoir is characterized by high initial production, rapid decline, short high?yield stage, low production in later stage followed by gradually steady state and keeping a long period of stabilized production. The threshold pressure gradient and the deformation coefficient have a great effect on production, the greater the gradient and coefficient, the lower the production of such a well will be. And the longer the horizontal wellbore length, the more the fracture number, the longer the fracture length and the bigger the flow conductivity, then the higher the production will be, but these values have their own optimum ranges