特低渗油藏大剂量微球深部调驱提高采收率技术实践

Enhanced oil recovery by deep profile control and flooding with high-dose microsphere in ultra-low permeability reservoir

特低渗油藏进入中高含水阶段后,受储层非均质性及注水长期冲刷形成高渗带影响,注水单向突进愈加突出,油藏含水上升速度加快,采油速度直线下降,控水稳产难度加大。微球调驱技术具有初始粒径小、吸水膨胀、弹性形变能力,易运移到地层深部,实现逐级深部调驱特点,进而扩大注水波及体积。本文根据油藏开发矛盾结合微球调驱特点,开展PV级微球大剂量深部调驱试验,历经三年多现场试验,试验区年含水上升率由4.5%下降到-2.1%,相比水驱递减采油速度提高0.38%,阶段累计增油1.85×10^(4)t,预测增加可采储量15.71×10^(4)t,采收率提高3.5%。

After the ultra-low permeability reservoir enters the middle and high water cut stage,the water injection one-way outburst becomes more and more prominent,the water cut rises faster,and the oil recovery rate drops linearly,because of the influence of reservoir heterogeneity and the long-term erosion of water injection to form the high permeability zone,it is more difficult to control water and stabilize production.Microsphere profile control and displacement technology has the characteristics of small initial particle size,water swelling,elastic deformation,easy migration to deep formation,realizing step-by-step profile control and displacement,and then enlarging the swept volume of water injection.According to the contradiction of reservoir development and the characteristics of microsphere profile control and displacement,the large dose deep profile control and displacement test of PV microsphere was carried out.After more than three years field test,the annual water cut rising rate of the test area was from 4.5%to-2.1%,compared with water flooding,the oil production rate is in creased by 0.38%,the oil production is increased by 18500 tons,the recoverable reserves are increased by 157100 tons,and the recovery factor is increased by 3.5%.