基于驱替压力梯度的稠油油藏水平井与定向井联合开发策略研究及应用

Research and Application of Joint Development Strategy of Horizontal Well andDirectional Well in Heavy Oil Reservoir Based on Displacement Pressure Gradient

根据稠油驱替特征采取相应的注采井网对提高开发效果具有重要意义。首先,利用岩心驱替实验与密闭取芯相结合,研究不同原油黏度下驱油效率与驱替压力梯度的关系,建立驱油效率和流度与驱替压力梯度的关系式;根据势的叠加原理,建立以驱替压力梯度和驱油效率为目标、融合井型、井距与井网的注采井网计算模型。结果表明,增大驱替压力梯度有利于提高稠油驱油效率,当原油黏度由60 mPa·s增加到120 mPa·s、180 mPa·s,有效驱替压力梯度由0.002 MPa/m增大至0.005 MPa/m、0.008 MPa/m。在相同井距条件下,水平井网较定向井网提高驱替压力梯度0.8~1.1倍、提高驱油效率8.0%~16.1%,从而大幅度提高水驱采收率6.4%~12.8%。上述认识应用于渤海秦皇岛油田多层砂岩稠油油田高含水后期开发,采取大规模利用水平井联合定向井深度开发策略,由初期定向井反九点井网调整为水平井联合定向井五点井网,采油速度由0.8%提高至1.5%~2.1%,含水上升率控制在0.6%左右,水驱采收率由24.5%提高至39.3%,极大改善开发效果,为类似油田提供经验。

It is of great significance to adopt corresponding injection-production pattern according to the characteristics of heavy oil displacement to improve the development effect.Firstly,the relationship between displacement efficiency and displacement pressure gradient under different crude oil viscosity was studied by using core displacement experiment and closed core extraction.According to the superposition principle of potential,a calculation model of injection-production pattern was established,which took displacement pressure gradient and displacement efficiency as targets,and integrates well type,well spacing and well pattern.The results show that increasing the displacement pressure gradient is conducive to improving the displacement efficiency of heavy oil.When the viscosity of crude oil increases from 60 MPa·s to 120 MPa·s and 180 MPa·s,the effective displacement pressure gradient increases from 0.002 MPa/m to 0.005 MPa/m and 0.008 MPa/m.Under the same well spacing condition,the displacement pressure gradient of horizontal well pattern is increased by 0.8~1.1 times,and the displacement efficiency is increased by 8.0%~16.1%,so that the water drive recovery rate is greatly increased by 6.4%~12.8%.The above knowledge is applied to the late high water cut development of Qinhuangdao multi-layer sandstone heavy oil field in Bohai Sea.The depth development strategy of large-scale use of horizontal well joint directional well is adjusted from the initial directional well reverse nine-point well pattern to the horizontal well joint directional well five-point well pattern.The oil production rate is increased from 0.8%to 1.5%~2.1%,and the water cut rise rate is controlled at about 0.6%.Water drive recovery rate increased from 24.5%to 39.3%,which greatly improved the development effect and provided experience for similar oil fields.