不同驱替方式下复模态微观孔隙原油动用规律——以克拉玛依油田530井区八道湾组油藏为例

Displacement Law of Crude Oil in Micro-pores under Different Oil Displacement Modes:Taking Badaowan Formation in Well Block 530 of Karamay Oilfield as an Example

通过一系列室内物理模拟驱油实验,结合微米CT扫描结果,对克拉玛依油田砾岩油藏水驱与聚合物驱的微观孔隙原油动用规律及剩余油分布特征进行研究。结果表明:水驱主要动用大于20μm孔隙的原油,对小孔隙原油的动用程度比较低,水驱后剩余油主要以连片状分布为主,赋存在小于20μm的孔隙中,水驱油效率为41.4%;聚合物驱主要动用8~20μm孔隙中的原油,对小孔隙原油的动用程度比较高,聚驱后连片状剩余油大量减少,主要以孔隙角隅状剩余油为主,赋存在小于10μm的孔隙中,聚合物驱油效率达到79.4%。在水驱油的基础上可以将油藏采收率提高38%。聚合物驱对水驱后小孔隙原油的有效动用是提高油藏采收率的主要方式,成为注水老油田稳产增产的重要技术手段。

The crude oilproduction lawand residual oil distribution characteristics of water flooding and polymer flooding in the conglomerate reservoir of Karamay Oilfield are studiedthrough a series of laboratory physical simulation oil displacement experiments and micron CT scanning results.The results show that water flooding mainly drives the crude oil in the pores whose diameter is more than 20μm,the recovery degree of the crude oil in small pores is relatively low.After water flooding,the remaining oil is continuously distributed in flakesin the pores whose diameter is less than 20μm,the water displacement efficiency is 41.4%.Polymer flooding mainly displaces the crude oil in the pores whose diameter is 8~20μm pores,and the crude oil in small pores has a high recovery degree.After polymer flooding,the residual oil distributed in flake is greatly reduced,the residual oil mainly distributes at the corner of the pores whose diameter is less than 10μm,and the polymer flooding efficiency reaches 79.4%.On the basis of water flooding,the polymer flooding can increase oil recovery by 38%.The polymer effectively displacing the residual crude oil in small pores after water flooding is the main way to improve the recovery factor of reservoir,and has become an important technical means to stabilize production and increase production in water injection old oilfields.