三塘湖油田牛圈湖区块西山窑组油藏注水开发对策

三塘湖油田牛圈湖区块西山窑组油藏为特低渗、低压、低流度的“三低”砂岩油藏,在开发初期存在注水开发效果差、产量低等问题。为了提高注水开发效果,通过生产动态统计分析、油藏工程和数值模拟方法研究,重新界定了注水技术政策界限,实施超前温和注水,同时论证了合理的井网井距,实施井网加密调整,并刻画出有利建产区,实施滚动建产。通过一系列对策实施,牛圈湖区块西山窑组油藏注水开发状况逐步好转,直井开发区地层压力保持平稳,含水率控制在55%以内,产油量自然递减率下降到10%左右,采油速度最高达1.04%,目前仍保持在0.70%以上,产油量保持稳定,预测牛圈湖区块西山窑组油藏南区和东区的采收率分别为24.5%和18.1%,好于开发方案标定的18.0%。

Water Injection Development Strategies for the Reservoirs of Xishanyao Formation in

The reservoirs of Xishanyao formation in Niujuanhu block of Santanghu oilfield are sandstone reservoirs with the characteristics of low permeability, low pressure and low mobility. In the early stage of development, there were problems such as poor water injection effects, low production of oil wells, and etc. In order to improve development effects of water injection, through the analysis of production performance statistics and the study on reservoir engineering and simulation methods, the technical and strategic limits for water injection were redefined, and the moderately advanced water injection was implemented. Meanwhile, reasonable well patterns and well spacing were discussed, the adjustment and the infilling in well patterns were implemented, and the favorable areas were depicted to prepare for rolling production. After the implementation of a series of strategies, the water injection development status for the reservoirs of Xishanyao formation in Niujuanhu block has gradually become better. At present, the reservoir pressure stays stable, the water content is controlled within 55%, and the natural decline rate of oil production drops to about 10%. The oil production remains stable and the maximum oil production rate can reach as high as 1.04%, which is still above 0.70% currently. It is predicted that the oil recovery rates of the southern and eastern areas of the reservoir in Xishanyao formation in the Niujuanhu block are 24.5% and 18.1%, respectively, both of which are higher than 18.0% calibrated in the development plan.