Investigating the mechanics of two-phase flow in rock fractures and caprocks

研究岩石裂隙和盖层中两相流的力学

• 批准号: 262466-2006
• 负责人: Hawkes, Christopher
• 金额: $ 1.75万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2007
• 资助国家: 加拿大
• 起止时间: 2007-01-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=364915
• 关键词: Investigating; mechanics; two; phase; flow

The growing threat of global warming is driving the need to sequester CO2 in saline aquifers and depleted oil and gas reservoirs. CO2's ability to invade reservoir pore space is governed by multi-phase flow mechanics, as it must flow into pores containing native groundwater and, in some cases, hydrocarbons. In reservoirs consisting of fractured rocks, most of the flow occurs through a network of natural fractures. While the mechanics of single-phase flow in fractured rocks are reasonably well understood, there is considerable uncertainly regarding the mechanics of two-phase flow within fractures. In order for any reservoir to retain CO2 for long periods of time, it must be overlain by fine-grained caprocks that prevent the upwards migration of CO2. CO2 cannot invade caprock pore throats until its pressure exceeds the capillary pressures in these throats. As such, the geometry of the caprock pore network has a critical impact on the pressure at which CO2 breakthrough will occur. There is limited experience conducting gas breakthrough tests with CO2, and in correlating caprock pore structure to breakthrough pressure. The short-term objectives of the proposed research are (1) to measure two-phase flows in caprocks and fractured reservoir rocks, and (2) to identify and quantify the parameters that control them. The long-term objectives are to develop methods for (1) quickly and confidently identifying good caprocks, and (2) maximizing the storage capacity of fractured reservoirs. This research will be conducted using the researcher's Rock Mechanics laboratory, supplemented by novel equipment and techniques such as the synchroton microscope at Saskatoon's Canadian Light Source, and a purpose-built fracture flow visualization cell. The benefit of this research to society will be a reduction in greenhouse gas emissions. Economic benefits will include enhanced recovery of oil from aging reservoirs that are used for CO2 storage, and possibly the trading of carbon credits as governed by international agreements such as the Kyoto protocol.

全球变暖的威胁越来越大，促使人们需要在含盐含水层和枯竭的石油和天然气储藏层中封存二氧化碳。二氧化碳侵入储集层孔隙空间的能力受多相流力学支配，因为它必须流入含有本地地下水的孔隙中，在某些情况下，还必须含有碳氢化合物。在由裂隙岩石组成的储集层中，大多数渗流都是通过天然裂缝网络进行的。虽然裂隙岩石中的单相流的力学已被很好地理解，但关于裂隙内的两相流的力学仍有相当大的不确定性。为了让任何储集层能够长期保留二氧化碳，它必须被细粒的盖层覆盖，以防止二氧化碳向上迁移。二氧化碳不能侵入盖层孔喉，除非它的压力超过这些喉道内的毛细管压力。因此，盖层孔隙网络的几何形状对发生二氧化碳突破的压力具有关键影响。在用二氧化碳进行气体突破测试以及将盖层孔隙结构与突破压力进行关联方面，经验有限。拟议研究的短期目标是(1)测量盖层和裂缝性储集岩中的两相流动，以及(2)识别和量化控制它们的参数。长期目标是开发(1)快速、自信地识别良好盖层的方法，以及(2)最大限度地提高裂缝性储集层的存储能力。这项研究将利用研究人员的岩石力学实验室进行，并辅之以新的设备和技术，如萨斯卡通加拿大光源的同步显微镜和专门建造的裂缝流动可视化单元。这项研究对社会的好处将是减少温室气体排放。经济效益将包括从用于二氧化碳储存的老化储油罐中更好地回收石油，并可能按照《京都议定书》等国际协议的规定进行碳信用交易。