考虑黏滞性低渗透油藏数值模拟应用研究

Application of Numerical Simulation in Low Permeability Reservoirs Considering Viscosity

针对低渗透油藏剩余油预测精度低的问题,以鄂尔多斯盆地延长组长7致密油藏为例,运用油藏数值模拟理论,引入黏滞性运动方程,描述低渗透油藏压力传播的方向和大小,将其成果运用到剩余油研究中,并对剩余油富集区优化部署挖潜井。研究结果表明:随着生产时间的延长,不考虑黏滞性会导致采收率偏低,见示踪剂情况证实了黏滞性对生产的影响;考虑黏滞性的低渗透油藏数值模拟结果生产历史拟合较好,单井拟合率达到89%;数值模拟结果表明,剩余油富集区主要位于水线两侧,为井间难以波及或注采不完善区域。在剩余油富集区域部署的挖潜井初期日产油为12.8 t/d,较邻井提高了近4倍,区域部署挖潜井预计增加可采储量9.27×10^(3)t。研究成果对同类油藏剩余油挖潜和后期调整有借鉴意义。

To address the problem of low prediction accuracy of remaining oil in low-permeability reservoirs,taking Chang 7 tight reservoir in Yanchang Formation in the Ordos Basin as an example,the reservoir numerical simulation theory is applied,and the viscous motion equation is introduced to describe the direction and magnitude of pressure propagation in low permeability reservoirs.The results were applied to the study of remaining oil,and the potential tapping wells were optimally deployed in the remaining oil-enriched areas.The research result shows:With the extension of production time,the recovery factor will be underestimated without considering the viscosity,and the tracer tracing situation confirms the influence of viscosity on production;the numerical simulation results of low-permeability reservoirs considering viscosity have a good production history fit,with a single well fit rate of 89%;the numerical simulation results show that the remaining oil-enriched area is mainly located on both sides of the waterline,which is the area difficult to sweep between wells or the area with imperfect injection and production.The initial daily oil production of the potential tapping wells deployed in the remaining oil-enriched area is 12.8 t/d,which is nearly 4 times higher than that of the adjacent wells.The potential tapping wells deployed in the region are expected to increase the recoverable reserves by 9.27×10^(3)t.The research results have reference significance for the potential tapping and later adjustment of remaining oil in similar reservoirs.