储层渗透率各向异性对垂直裂缝井产能的影响

Effect of heterogeneity of reservoir permeability on the production of vertical fractured wells

压裂油井产能评价是进行压裂设计的基础,已取得的研究成果主要针对均质油藏,对储层各向异性油层垂直裂缝井产能未曾涉及.考虑各向异性地层稳定点汇压力分布,将垂直裂缝抽象为一条斜直线汇,根据汇源叠加积分原理得到各向异性地层垂直裂缝井产能通用表达式;应用Gringgarten A G等提出的近似方法,求得无限导流垂直裂缝井的稳态压力分布解及各向异性地层当量井径.计算结果表明:对各向异性油藏,为获得最大的产能,应使裂缝延展方向垂直于主渗透方向.该方法可广泛应用于非均质油藏垂直裂缝井产能评价.

The productivity evaluation of fractured well is the most important procedure for fracturing design.The method of productivity evaluation of fractured well in a homogeneous reservoir cannot be applied to the heterogeneous reservoir.According to the pressure distribution of a steady-state point sink in an anisotropy reservoir,the pressure distribution of a vertical fracture can be obtained by taking the fracture as a slanted line sink.The general productivity equation of vertical fracture can be presented by means of the principle of superposition in an anisotropy reservoir.Applying the approximate method proposed by Gringgarten et al,the solution of steady-state pressure distribution and the equivalence radius of the fracture can be achieved.In order to obtain maximum productivity for heterogeneous reservoir,the fracture should be perpendicular to the direction of the main permeability.Also,this new method unifies the productivity evaluation of fractured wells in homogeneous and anisotropy reservoirs and can be widely used in productivity evaluation for heterogeneous reservoirs with vertical fractures