渤海稠油油田高含水期提高水驱采收率技术研究及应用

为探索稠油油田进入高采出程度、高含水率阶段提高水驱采收率的新技术,改善油田开发效果,以渤海S稠油油田为例,开展了高倍数水驱技术研究和联合井网注水方法研究。其中,高倍数水驱实验结果表明,当驱替倍数达到300~400倍时,与驱替倍数30~50倍时相比,驱油效率提高约10%,为S油田提高水驱采收率提供了方向;利用灰色关联分析方法所建立的多因素调控注水方法,综合考虑了有效厚度、渗透率、注采井距、注采井数、方向地层系数等因素,能够满足S油田具有海上特色的水平井与直井联合井网的注水需求。将研究成果在S油田G区应用后,G区2016―2019年自然递减率由6.0%降低至4.4%,含水上升率由2.2%降低至1.8%,改善了G区的开发效果,表明该方法对海上注水开发油田进入高含水期后的调整具有一定的指导意义。

Research and application of water flooding recovery technology in high water cut stage of Bohai heavy oil field

To explore new technology of improving water flooding recovery and development effect when heavy oil field enters the stage of high recovery degree and water cut,taking S heavy oil field of Bohai sea as an example,the research on high multiple water flooding technology and combined well pattern water injection method are carried out.The results of high multiple water flooding show that when the displacement multiple reaches 300~400 times,the oil displacement efficiency is increased by about 10%compared with that of 40 times,which provides a direction for S oilfield to enhance oil recovery by water flooding.Meanwhile,a multi factor control water injection method has been established by the grey correlation analysis method,which considers the effective thickness,permeability,injection production well distance,injection production well number and directional formation coefficient and other factors,which meet the water injection demand of combined well pattern.After the research results are applied in G area,the natural decline rate is reduced from 6.0%to 4.4%and the water cut increase rate is reduced from 2.2%to 1.8%in 2016-2019,which improves the development effect.Results show this method has a good reference for the adjustment of offshore water flooding oilfield after entering high water cut stage.