Liao Xinwei

Methodology for estimation of CO2 storage capacity in reservoirs

Abstract The CO 2 storage in reservoirs is one of the most effective ways of reducing the greenhouse gas emission, which is based on the mechanisms of structural and stratigraphic trapping, residual gas trapping, dissolution trapping and mineral trapping. The CO 2 storage capacity in oil reservoirs includes theoretical, effective, practical and matched storage capacities. In the estimation of the CO 2 storage capacity in both waterflooding and CO 2 flooding oil reservoirs, theoretical and effective storage capacities can be obtained by the material balance and analogy methods. The theoretical storage capacity represents the physical limit of what the reservoir system can accept. The effective storage capacity represents a subset of the theoretical capacity and is obtained by applying a range of technical cut-off limits to a storage capacity assessment which incorporate the cumulative effects of reservoir and fluid parameter. When the material balance method is used, the amount of CO 2 dissolution is not negligible. In using the analogy method, the key is to determine CO 2 utilization factor. Examples show that the method is simple and convenient for the estimation of the CO 2 storage capacity in China.

特低渗透油藏注CO 2 驱参数优化研究

安塞王窑区长6储层属于特低渗透油藏, 经过多年的注水开发, 目前已进入中高含水期, 注水开发的矛盾日益突出, 进一步提高水驱采收率难度大。CO 2 驱在一定程度上能够弥补水驱的不足, 是特低渗透油藏提高采收率的一种重要方式。以安塞王窑区长6特低渗透油藏为研究对象, 分析了该区块的地质特征和注水开发中存在的问题, 应用地质建模技术和油藏数值模拟技术优选了适合该试验区的CO 2 驱开发方式, 并且进一步优化了地层压力、采油速度、水气交替时间、关井气油比和总注气量等参数。此次研究成果将为CO 2 混相驱现场试验流程建设、试验的实施提供基础参数, 对安塞油田全面实施CO 2 驱油技术具有参考和借鉴作用。