川北油田SL2裂缝系统油藏提高采收率技术研究

Research on EOR Technique of SL2 Fracture Oil Reservoir in North Sichuan Oilfield

川中隆起大安寨段薄层状介壳灰岩裂缝油藏,具有无底边水、定容封闭和未饱和特征。川北油田SL2裂缝系统油藏自衰竭式开采以来,弹性驱和溶气驱采收率只有14.71%,低渗储集层产出能力受多种因素综合影响,上覆应力敏感极强,裂缝导流能力明显降低,连通性变差,剩余石油地质储量被分割。为此,从直井和水平井压裂酸化、层内燃爆、增能驱油和热采等方面进行了技术对策探讨,扩大了开采技术选择范围,有利于超前科学决策。

The thin layer and shelly limestone oil reservoirs at Da＇anzhai Interval in the middle part of Sichuan Uplift have the characteristics of no bottom and side water,isochoric closing and unsaturating.Since the fractured oil reservoirs in North Sichuan Oilfield are produced by natural depletion,the oil recovery factor of elastic drive and dissolved gas drive has only been 14.71%.The production capacity of low permeability reservoir is affected by many factors.The sensibility of overlying stress is very strong,the fracture conductivity obviously declines and the connectivity becomes poor.The residual petroleum in-place is divided.Therefore,this paper discusses on the techniques and countermeasures of horizontal and vertical well fracturing,in-situ combustion ,increasing energy and flooding oil and thermal recovery,which expends the scope of production technique choice and is favorable for advancing science decision.