超低渗透油藏超前注水开发效果分析及对策

长63油藏属超低渗低压油藏,天然能量较弱。超前注水后全面投入开发,投产初期单井产量低,含水率变化稳定,部分油井压力下降,部分注水井压力上升。研究认为:在目前井网条件下,部分井组井距过大,没有建立起有效的驱替压力系统,要形成有效驱替必须缩小井距;笼统注水使得注采层位不对应,造成油井产液量较低。通过研究,提出下步调整措施,即进一步细分层系,加密井网,缩小注采井间的距离。现场实施后效果显著。

Effect analysis and countermeasures of advanced water flooding for ultra-low permeability reservoirs

The Chang 63 reservoir is an ultra-low permeability,low pressure reservoir with week natural energy.After advanced water injection,the reservoir was put on full-scale production.In the early production period,per well production was low,water cut was stable,and pressure dropped in some oil wells while rose in some water injection wells.It has been realized through research that with present well pattern,well spacing is too large to establish effective driving pressure system in some well groups,and it is necessary to reduce well spacing in order to form effective flooding;in addition,commingled water injection has resulted in non-corresponding horizons of injection to production,leading to low liquid production from oil wells.The adjustment measures proposed through the research include further subdividing layers,infilling well pattern,and reducing injection-production well spacing.