缝网压裂裂缝形态对低渗油藏渗吸采油效果影响实验

INFLUENCE EXPERIMENT OF THE FRACTURE MORPHOLOGY OF THE NETWORK FRACTURING ON THE EFFECTS OF THE IMBIBITION RECOVERY FOR LOW PERMEABILITY OIL RESERVOIRS

大庆油田外围地区低渗油藏储量非常丰富,但由于缺乏有效的开发手段,采出程度比较低。渗吸采油是(弱)亲水低渗油藏有效开发的技术措施之一。以大庆外围扶余储层流体性质和地质特征为模拟对象,在仿真模型上开展缝网压裂裂缝长度和条数对渗吸采油效果影响实验。研究结果表明:随缝网压裂裂缝主缝长度和分支缝数量增加,渗吸面积增加,油水交渗作用增强,渗吸采收率增加,但增幅逐渐减小;"渗吸液+增能剂"组合使用能够产生原油降黏、补充驱替动力和油水交渗等3因素间协同效应,可以大幅度提高渗吸采油效果,采收率增幅超过15%。

The reserves of the low-permeability reservoirs in the peripheral area of Daqing Oilfield are very rich,however,the produced degree of the reserves is rather low due to the lack of the effective developing methods. The imbibition recovery is one of the effective technical measures which are used to develop the（ weak） hydrophilic and low-permeable reservoirs. On the basis of the simulations of the fluid properties and geological features of Fuyu reservoirs in Daqing peripheral area,the influence experiment ofthe fracturelength and number of the network fracturing on the effects of the imbibition were carried out on the simulating model. The study achievements show that with the rises of the mainfracture length and numberof branchfracture,the imbibition area increases as well,the cross-filtration between the oil and water enhances at the same time,thus the imbibition recovery factor increases,but the incremental amplification gradually decreases; thecombined ＂imbibing solution ＋ energy increasing agent＂can be used to produce a synergistic effect among reducing the oil viscosity,supplying displacing force and crossfiltration between the oil and water,therefore the effects of the imbibition recovery can be improved to a great deal,the amplification of the recovery factoris more than 15%.