致密储层CO2驱油实验

Oil displacement experiment of CO2 flooding in tight reservoir

唐万举 邓学峰 卢瑜林 王萍 斯容 周志峰3

中国石化华北油气分公司，河南 郑州 450006 中国石化华北油气分公司石油工程技术研究院，河南 郑州 450006 中国石化中原油田分公司濮东采油厂，河南 濮阳 457001

Huabei Oil & Gas Company, SINOPEC, Zhengzhou 450006, China Research Institute of Petroleum Engineering and Technology, Huabei Oil & Gas Company, SINOPEC, Zhengzhou 450006, China Pudong Oil Production Plant, Zhongyuan Oilfield Company, SINOPEC, Puyang 457001, China

HH油田主要开发层位长8油层为典型的致密储层，且裂缝发育。通过室内评价实验，选择CO2为该致密储层的能量补充介质。为进一步研究CO2在致密储层中的驱油规律，开展了裂缝岩心与基质岩心并联的CO2驱油实验。实验结果表明：裂缝中原油的渗流阻力远低于基质岩心，裂缝岩心中CO2驱替压力低、采收率高，基质岩心中CO2驱替压力高、采收率低，基质岩心注CO2受效时，裂缝岩心已经发生气窜且为主要的气窜通道；CO2泡沫能够封堵裂缝，但封堵能力有限，CO2泡沫驱提高基质岩心采收率幅度低，且随裂缝宽度增加泡沫封堵能力明显下降，提高采收率能力降低。

Chang 8 Formation, as the major development target of HH Oilfield, is a typical tight reservoir with fractures. CO2 was selected as the driving medium for enhancement of energy through laboratory experiments. In order to further study the displacement laws of CO2 flooding in tight formation, we conducted parallel core flooding experiments through cores with or without fractures. The results indicate that the flow resistance of oil in fractured cores is considerably lower than that in matrix cores. In addition, the fractured cores show low displacement pressure and high oil recovery, while the matrix cores indicate high displacement pressure and low oil recovery. When there appears effective oil increase in the matrix cores during CO2 flooding, the fractured cores has developed major dominant channel of CO2. Meanwhile, it is proved that the CO2 foam could plug the fractures with limited capability. The extent of enhanced oil recovery through CO2 foam flooding in matrix cores is low. Also, with the increase of width of the fractures, plugging ability of CO2 foam declines significantly, and the ability of enhancing oil recovery decreases as well.

10.6056/dkyqt201806014