复杂断块油藏三级细分技术的研究与应用——以永安镇油田永3-1断块沙二段7—9层系为例

Research and application of three-class subdivision technique on complex fault block reservoirs-a case study of Es_2 7-9 layer series of Yong 3-1 fault block in Yonganzhen oilfield

复杂断块油藏由于层间、层内非均质性以及开发非均质性的存在,导致开发不均衡。随着开发的不断深入,层间干扰矛盾越来越突出,多次细分后再进行层系分段细分经济效益变差。减缓干扰、均衡注采、扩大水驱波及体积,是大幅度提高这类油藏水驱采收率的关键。以永安镇油田永3-1断块沙二段7—9层系为例,采用层系重组、油井分层采油、水井分层注水以及油水井变孔密射孔完井等技术,逐级减缓层间干扰,形成复杂断块油藏三级细分技术。在其先导试验区取得了较好的应用效果:单元产油量从11.5 t/d上升到54.1 t/d,综合含水率从83.4%下降到77.6%,为同类型油藏提高水驱采收率提供了新思路。

Owing to the heterogeneity within and between the layers as well as the unbalanced development caused by heterogeneity during the process of development, and also to the deepening of development, the interference between layers of complicated fault block reservoirs is getting more and more apparent. After being subdivided many times, the further subdivision lacks essential substance basis. How to further reduce interference so as to maintain balanced injection and production and how to increase water drive performance are the most critical key techniques for this kind of reservoirs, as well as the significant enhancement of oil recovery factor range of water-flooding. This article takes Es2 7-9 layer series of Yong 3-1 fault block as an example and puts forward three-class subdivision technology, including recombining of layer series to effectively reduce interference, separating layer of water injection and production, and variable density perforation. This technique has been used in development adjustment in the pilot test, and has obtained a good effect. This article also provides a new pattern, method and technique for the same kind of reservoirs to enhance oil recovery efficiency of water-flooding.