单层开采的封闭边界2层越流油藏井底压力的精确解及典型曲线

EXACT SOLUTION AND TYPICAL CURVE OF BOTTOMHOLE PRESSURE ON CONFINED TWO LAYER CROSSFLOW RESERVOIR PERFORATED PARTIALLY

由于沉积环境不同 ,油藏通常由不同性质的多个油层组成 ,各层之间通过井筒和层间越流而相互影响。因为经济上的考虑和技术条件的限制 ,对多层油藏往往只打开其中的若干层进行生产。采用有效井径的概念 ,在考虑表皮效应和井筒储存影响的条件下 ,建立了封闭边界的 2层越流油气藏单层开采时井底压力的动态模型。通过拉氏变换得到拉氏空间下以Bessel函数表示的精确解。运用Crump数值反演方法 ,得到了实空间的解 ,分析了压力动态特征。

Reservoirs are often composed of many layers of quite different properties. Each layer is influenced by the others, not only through the wellbore, but also through crossflow between layers. The effective hole diameter mathematical model describing flow of slightly compressible fluid through a two layer crossflow reservoir perforated partially is solved rigorously with consideration of wellbore storage and skin effect. The exact solutions obtained for a well producing at a constant rate from a radial drainage area confined outer boundary condition are expressed in terms of ordinary Bessel functions. The numerical computation of these solutions is made by Crump numerical inversion method and the behavior of the systems is studied as a function of various reservoir parameters. The new model is numerically stable. The typical curve in confined formation condition is drawn up by numerical inversion method.