姬塬油田长63超低渗油藏注采效果评价

姬塬油田长6₃油藏属于超低渗油藏,现有井网难以形成有效的驱替压力系统,油藏趋于衰竭开采,亟需对现有井网的注采效果进行评价,为后续井网加密调整提供理论支持。为此,优选出水驱储量控制程度、地层压力保持水平、注采静压差、见效比例、见水比例、投产满2年单井产能、水驱储量动用程度、水驱体积波及系数和动态采收率9个评价指标,引入综合权重,建立了基于未确知测度的超低渗油藏井网注采效果评价模型,对研究区长6₃油藏进行了井网注采效果评价。评价结果表明,姬塬油田长6₃油藏井网的注采效果差,需要立即进行井网调整。评价结果符合油藏目前的生产状况,证明了评价模型的准确性,为超低渗油藏现有井网注采效果评价提供了一种新的思路和方法。

Evaluation of Injection-Production Effect of Chang 63 Ultra-Low Permeability Reservoir in Jiyuan Oilfield

The Chang 6₃ reservoir in Jiyuan oilfield is an ultra-low permeability reservoir. As an effective displacement pressure system is difficult to form in the existing well pattern and the reservoir tends to be depleted, it is urgent to evaluate the injection-production effect of the existing well pattern and provide technical support for subsequent adjustment on well pattern infilling. Therefore, nine indexes for evaluating injection-production effect were selected, including reserves control degree of water flooding, pressure maintenance level, injection-production static pressure difference, flood response ratio, water breakthrough ratio, single-well productivity over two years, reserves producing degree of water flooding, sweep coefficient of water flooding, and dynamic recovery rate. Comprehensive weights were introduced to establish an injection-production effect evaluation model for well pattern in ultra-low permeability reservoirs based on unascertained measurements, helping to evaluate the injection-production effect of Chang 6₃ reservoir in the study area. The evaluation results show that the injection-production effect of the well pattern in this reservoir is poor, and the well pattern needs to be adjusted immediately. The evaluation results are consistent with the current production status of the reservoir, which proves the accuracy of the evaluation model, and provides a new idea or method for evaluating injection-production effect of existing well pattern in ultra-low permeability reservoirs.