高含水期井损对高渗透油藏开发效果的影响

The influence of well loss on development effect in the high permeability reservoir at high water cut stage

中国陆上油田已整体进入高含水开发期,大量生产井和注入井因各种原因关停频繁,导致井网完善性遭到破坏,油藏开发效果变差。准确揭示生产井和注入井井损对油藏开发效果的影响规律,为井损恢复措施制定提供决策依据是十分必要的。通过定义油藏可采储量损失百分数,并将其作为井损条件下油藏开发效果评价指标,定量分析了井损因素对高渗透油藏开发效果的影响。研究结果表明:当发生井损时,随井损时刻变晚,相对高渗透部位井的油藏可采储量损失百分数先升高后降低,相对低渗透部位井的油藏可采储量损失百分数单调上升;同一井损时刻下,相对低渗透部位井的油藏可采储量损失百分数大于相对高渗透部位井,且在渗透率非均质条件下井损位置的影响明显,渗透率均质时井损位置的影响幅度很小;同一井损时刻,随渗透率平面变异系数增大,相对高渗透部位井的油藏可采储量损失百分数减小,相对低渗透部位井的油藏可采储量损失百分数增大;同一井损百分数下,生产井的油藏可采储量损失百分数高于注入井,井损后应优先恢复生产井。

Chinese onshore oilfields have generally stepped into high water cut stage. A large number of wells shut down frequently for various reasons,which results in a damaged well pattern and poor reservoir development effect. It's necessary to accurately reveal the influences of the well loss on the reservoir development effect so as to provide decision-making basis for well loss recovery measures. The loss percentage of reservoir recoverable reserves was defined and taking as an evaluation index of the reservoir development effect under the condition of well loss. The influences of well loss on the development effect in the high permeability reservoir were analyzed quantitatively. The results indicate that with the course of well loss time,the loss percentage of reservoir recoverable reserves increases first and then reduces for the relatively high permeability wells,and it increases for the relatively low permeability wells monotonously;at the same moment of well loss,the loss percentage of reservoir recoverable reserves for the relatively low permeability wells is greater than that for the relatively high permeability wells. Meanwhile,the impact of well loss position under heterogeneous permeability condition is obvious and that under homogeneous permeability condition is weak;at the same moment of well loss,with increasing planevariation coefficient of permeability,the loss percentage of reservoir recoverable reserves reduces for the relatively high permeability wells and increases for the relatively low permeability wells;the loss percentage of reservoir recoverable reserves of the production wells is higher than that of the injection wells with the same well loss percentage. Priority should be given to recover the production well.