三叠系特低渗透裂缝性A油藏中高含水鞭合理注采比研究及应用

Research and application of reasonable injection to production ratio of Triassic fractured reservoir A with ultra-low permeability at mid-to-high water cut stages

三叠系特低渗透裂缝性A油藏地层压力系数低为0．66，注水开发初期为提高地层能量，保持较高采油速度，将注采比控制在大于3．2，导致地层压力快速上升，油井综合含水率快速上升，油藏递减率大，油藏开发效果差以物质平衡和注采平衡原理为基础，运用多种方法并重点考虑了无效注水量的影响，确定了油田中含水期开发的合理注采比为2．8．根据研究结论，及时将A油藏注采比调整至2．8，开发效果较好。

The formation pressure coefficient of Triassic fractured Reservoir A with ultra-low permeability is low （0. 66）. In the early waterflooding, in order to improve the formation energy and to maintain a high production rate, the injection to production ratio is controlled to be greater than 3.2. This resulted in rapid increase of the formation pressure, and the comprehensive water cut of the oil wells is rapidly rising, with large production decline rate, and poor result of reservoir development. Based on the principles of material balance and balanced injection and production rate, the reasonably injection-production ratio of 2. 8 in lhe medium water-eut of the field is determined by use of a variety of methods and fi）eusing on the consideration of t/he influence of ineffective water injection. According to the research findings, the injection-production ratio of the Reservoir A was timely adjusted to 2. 8, obtaining a good development resuh.