考虑井筒变质量流动的溶解气驱油藏水平井流入动态特性研究

Study on characteristics of horizontal well inflow performance considering variable mass flow in solution gas drive reservoirs

目前,国内外研究学者应用数值模拟方法研究溶解气驱油藏水平井流入动态时未考虑井筒流动的影响,对于高产、小井径水平井会产生较大的计算误差。针对存在的问题,使用Eclipse油藏数值模拟软件中考虑井筒变质量流与油层中渗流耦合的多段井模型,研究了井筒变质量流动对溶解气驱油藏水平井流入动态的影响。模拟结果表明:当油藏压力较高时,不同油藏衰竭程度时水平井无因次IPR曲线基本重合;但当油藏压力较低时,溶解气析出,油相饱和度减少,油相相对渗透率降低,油藏内两相渗流阻力和水平井筒内两相流动阻力增大,水平井无因次IPR曲线上凸趋势迅速增大。

At present,solution-gas drive reservoirs inflow performance of horizontal wells has been studied by many researchers using numerical simulation method,but the effect of variable mass flow in horizontal wellbore are not considered,which may lead to calculation error for high-yield or small-diameter horizontal wells.Aiming at the problem above,solution-gas drive reservoirs inflow performance of horizontal wells is studied by using multi-segment well model which couples the reservoir and horizontal well variable mass flow dynamics by Eclipse Reservoir Simulation Software.The effects of variable mass flow in horizontal wellbore on solution-gas drive reservoirs inflow performance are analyzed by simulation calculation.The numerical results indicate that when reservoir pressure is high,the horizontal well dimensionless IPR curves of different reservoir failure degree are basically superposing;but when reservoir pressure is low,because of the precipitation of dissolved gas,oil phase saturation and relatively permeability decrease,the two-phase seepage resistance within reservoir and the two-phase flow resistance in the wellbore increases,so the upper convex trend of the horizontal well dimensionless IPR curves increases rapidly.