水平井变密度射孔技术优化及应用

由于水平井水平段物性差异、井斜角变化、水平段内摩擦损失等因素造成水平段开发不均衡。根据渗流力学和油藏工程理论,建立了油藏渗流模型、孔眼紊流模型、水平井井筒流动模型;基于流体的不同流动状态之间边界处压力及流量相等,根据质量守恒方程,建立了油藏—水平井井筒流动耦合模型。并利用油藏—水平井井筒流动耦合模型分析了井斜角、渗透率、水平段距底水的距离、原油粘度对孔密优化的影响。结果表明,井斜角小于等于90°时,从跟端到趾端需增加孔密,井斜角大于90°时,从跟端到趾端需减小孔密;渗透率大的井段,渗流阻力小,向渗透率大的方向降低孔密;距离底水越近孔密差异越大。应用油藏—水平井井筒流动耦合模型对11口水平井进行变密度射孔优化,优化后平均单井初期产液量为32.9m3/d,产油量为29t/d,平均单井累积增油量为5246t,与2008—2009年投产的同类型相邻油藏水平井相比,平均含水率上升速度减缓,开发效果有所改善。

Research and application of variable density perforation of horizontal well

Because of difference of physical property, alternation of deviation angle, friction loss in horizontal bore hole,the development within the horizontal interval is not balanced. According to the fluid mechanics in porous medium and reservoir engineering,the model of horizontal well fluid mechanics, turbulent flow model of eyehole and hole model of horizontal well are built in different reservoir. Meanwhile, the damage factor during drilling and damage factor during perforating are introduced into the new model. According to the mass conservation equation, flow couple model of reservoir and horizontal well hole are built. The effect of deviation angle, permeability, distance to bottom water, and viscosity to liquid producing balancing profile of horizontal well is analyzed by the model. By optimizing the perforation model of horizontal well, variable density perforation can achieve the liquid balancing producing for horizontal well hole. It was demonstrated that, compared to the previous horizontal well, the water cut rising is slow, and the production performance become better. Thus, variable density perforation of horizontal well is the new technique for enhance the reservoir balancing production.