致密油藏多段压裂水平井初始产能影响因素分析

Influencing factors analysis of multi-stage fractured horizontal wells' initial productivity in dense reservoirs

致密油藏中基质渗透率非常低,通过体积压裂产生的人工压裂缝,可以有效改变水平井筒附近的地应力分布,同时通过水力压裂缝为桥梁,来增强天然裂缝与水力裂缝、以及水平井筒之间的联系,从而改善致密油藏内的流体渗流。通过将致密油藏划分为三个渗流区域,并假设线性流为三个流动区域中主要流动特征,对体积压裂水平井的初始产能进行了分析。研究表明,适当增加水力压裂缝的条数、增加压裂缝的半长,有利于激活双重介质的致密油藏中天然微裂缝,从而增加产能。

The matrix permeability of dense reservoirs is very low and through artificial pressure cracks by volume fracturing,the stress distribution around wellbore can be effectively changed.Meanwhile through hydraulic fractures as a bridge,the natural fractures and hydraulic cracks,as well as links between the horizontal wellbore can be enhanced.And therefore the flow of dense fluid within the reservoir can be enhanced.The dense reservoir can be divided into three seepage areas,and assuming a linear stream flow as the main flow characteristics for the three areas,the initial production volume of fractured horizontal wells have been analyzed.Study results show that properly increasing the number of cracks beat water and increasing pressure fracture half-length will be helpful to activate the dual medium dense reservoir of natural micro-cracks,and then increase productivity.