碳酸盐岩油藏提高采收率研究的新认识:固液界面影响

New insights of enhancing oil recovery in carbonate reservoir:effects of solid/liquid interface

碳酸盐岩油藏开发是目前增加我国原油产量的主攻方向之一.本文针对碳酸盐岩油藏岩石及模拟岩石样品开展固液界面作用的研究工作,从岩石的化学组成、比表面积、表面荷电情况、接触角及表面活性剂吸附量等方面,系统考察了方解石、白云石以及中东油藏碳酸盐岩样品在洗油过程中的固液界面相互作用结果,并分析了相关体系的洗油效率.结果证实了方解石、白云石样品与中东油藏碳酸盐岩样品在组成、结构及表面性质等方面高度一致,可用于碳酸盐岩油藏固液相互作用研究的模拟样品.进而揭示了表面活性剂在碳酸盐岩表面吸附量低、对其表面润湿性改变小且洗油效率相关性差的特点,表明固液界面相互作用不是影响碳酸盐岩油藏提高采收率效果的关键因素.

Exploitation of the carbonate reservoir is considered to be one of the main strategies to increase the crude oil output in China.In this article,we investigated the solid/liquid interface interaction on the carbonate reservoir rock samples(from Middle East reservoir) as well as the simulated rock samples(calcite,dolomite).Specifically,the solid/liquid interface interaction in the process of oil washing was systematically investigated in many different aspects(chemical composition,specific surface area,surface charge,contact angle,surfactant adsorption capacity,etc.).While,the corresponding oil washing efficiency of the related system was determined.The results demonstrated that the calcite and dolomite samples were highly consistent with the Middle East carbonate reservoir rock samples in terms of composition,structure and surface properties.Therefore,they could be used as the simulation samples for the study of solid/liquid interaction in carbonate reservoir.Furthermore,our study revealed that the adsorption capacity of surfactant on the surface of carbonate rocks was low.Meanwhile,the change of surface wettability was small and it exhibited no obvious correlation with oil washing efficiency.These results indicated that the solid/liquid interface interaction was not the key point of impacting the enhanced oil recovery in carbonate reservoirs.