摘要
针对裂缝性油藏含水上升快、稳产难度大的问题，以渤海大型潜山裂缝性油藏——JZ潜山油藏为例，基于油井见水时间、见水强度及见水形态，划分了3类见水模式，即低缓稳定型、波动上升型和快速上升型，总结了3类见水模式下裂缝发育特征和生产特征。在此基础上，采用数值模拟技术并结合矿场实践，提出了一套适合裂缝性油藏的优化注水方式。研究结果得出：Ⅰ类、Ⅱ类、Ⅲ类见水模式，挖潜重心应逐步由提高基质系统采收率转变为扩大注入水的波及系数；3类注水方式分别采用脉冲注水、周期注水和异步注采，应逐步扩大阶段性压力变化幅度，注水半周期由2～3个月延长为4～6个月，累计注采比由0.95～1.00逐步降低为0.80～0.90。在该套技术的指导下，锦州A潜山油藏实现年增油14.5×104 m3，预计提高采收率1.5百分点。该项配套技术对于改善裂缝性油藏开发效果具有广泛的实用意义，为同类油藏的开发提供了借鉴。
Abstract
To solve the problems of rapid water cut rise and great production decline in fractured reservoirs, and take JZ buried hill reservoir, a large fractured reservoir in Bohai Sea, as an example, three types of water breakthrough modes are divided based on the water breakthrough time, water breakthrough strength and water breakthrough form of oil wells, which is low stable type, fluctuation rising type and fast rising type. The development and production characteristics of fractures under the three water breakthrough modes are summarized. On this basis, a set of optimal water injection methods suitable for fracture reservoir are proposed by combining numerical simulation technology with field practice. The result shows, from type Ⅰ water breakthrough mode to type Ⅲ, the direction of enhanced oil recovery has gradually changed from enhancing the recovery of the matrix system to expanding sweep efficiency of injected water. The water injection methods of the three types are pulse injection, cycle injection and asynchronous injection respectively. The range of periodic pressure changes are gradually expanded, the half-cycle of water injection is extended from 2-3 months to 4-6 months, and the cumulative injection-production ratio is reduced from 0.951.00 to 0.800.90. Under the guidance of this set of technologies, Jinzhou A reservoir has achieved an annual oil increase of 14.5×104 m3, with an estimated increase in oil recovery of 1.5%. This technology has extensive practical significance for improving the development effect of fracture reservoir and provides reference for similar reservoir development.
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