根据低渗透油藏CO2驱流体分布, 将渗流区划分为CO2区、CO2-原油过渡区和未波及原油区, 考虑过渡区内流体物性参数幂律变化, 建立变性质CO2驱三区复合油藏模型, 应用Laplace 变换及Stehfest 数值反演, 求得井底压力解, 绘制典型试井曲线, 研究试井曲线变化特征及其影响因素。结果表明, 过渡区流体流度、储容系数变化幂律指数和CO2区与过渡区交界面流度比、储容比分别影响CO2区与过渡区间的过渡段以及过渡区径向流直线段斜率;储容系数变化幂律指数、交界面储容比越大, 过渡区与原油区间的过渡段开始时间越早, 过渡段峰值越小;增大过渡区半径, 压力波在过渡区内传播时间增加, 过渡区径向流直线段延长, 过渡区向原油区过渡段曲线右移, CO2注入压力降低。
On the basis of fluid distribution of carbon dioxide flooding in low permeability reservoir, the flowing areas are divided into CO2 region, CO2-oil transition region and oil unswept region. Considering the power law variation of fluid physical parameters in the transition region, we establish a varied property carbon dioxide flooding three-zone composite reservoir well testing model, and obtain the solution of bottom hole pressure by applying Laplace transform and Stehfest numerical inversion. In this way, the characteristics of variation of the well testing curve and influential factors are investigated. The results show that the slope of curves representing the transition section between the CO2 region and transition region and radial flow of the transition region is mainly affected by the power law exponent of mobility and storativity and mobility and storativity ratio in the CO2-transition region interface. The larger the storativity power law exponent and storativity ratio at the CO2-transition region interface is, the earlier the transition section between miscible region and oil unswept region begins, the lower the peak is. When the radius of the transition region is increased, the line of radius flow in the transition region becomes longer, the transition curve from the transition to oil unswept region shifts right, and CO2 injection pressure decreases.
[1] 苏玉亮. 油藏驱替机理[M]. 北京: 石油工业出版社, 2009. Su Yuliang. Displacement mechanism in oil reservoir[M]. Beijing: Petroleum Industry Press, 2009.
[2] 高慧梅, 何应付, 周锡生. 注二氧化碳提高原油采收率技术研究进展 [J]. 特种油气藏, 2009, 16(1): 6-12. Gao Huimei, He Yingfu, Zhou Xisheng. Research progress on CO2 EOR technology[J]. Special Oil and Gas Reservoirs, 2009, 16(1): 6-12.
[3] Tang R W, Ambastha A K. Analysis of CO2 pressure transient data with two-and three-region analytical radial composite models[C]. SPE Annual Technical Conference and Exhibition, Houston, Texas, USA, October 2-5, 1988.
[4] Ambastha A K, Jr Ramery H J. Pressure transient analysis for a threeregion composite reservoir[C]. SPE Rocky Mountain Regional Meeting, Casper, Wyoming, USA, May 18-21, 1992.
[5] 王敬瑶. 二氧化碳驱试验区试井测试资料分析及应用[J]. 大庆石油学院学报, 2011, 35(3): 85-90. Wang Jingyao. Analysis of well testing data of carbon dioxide flooding zone and its application[J]. Journal of Daqing Petroleum Institute, 2011, 35(3): 85-90.
[6] 朱建伟, 邵长金, 廖新维, 等. 注二氧化碳混相驱试井模型及压力分析 [J]. 油气井测试, 2011, 20(4): 1-4. Zhu Jianwei, Shao Changjin, Liao Xinwei, et al. Miscible flooding well test model with carbon dioxide injection and its pressure analysis[J]. Well Tesing, 2011, 20(4): 1-4.
[7] 马代鑫, 刘慧卿, 邵连鹏, 等. 火烧油层注气井试井分析理论模型[J]. 油气地质与采收率, 2006, 13(5): 72-74. Ma Daixin, Liu Huiqing, Shao Lianpeng, et al. Theoretical model of well test analysis for gas injection wells of in-situ combustion[J]. Petroleum Geology and Rrecovery efficiency, 2006, 13(5): 72-74.
[8] 刘永良, 贾永禄, 康毅力, 等. 考虑热损失的稠油热采三区复合油藏试井模型[J]. 大庆石油地质与开发, 2008, 27(1): 78-82. Liu Yongliang, Jia Yonglu, Kang Yili, et al. Three-zone composite reservoir well testing model for heavy oil thermal recovery with consideration of heat loss[J]. Petroleum Geology & Oilfield Development in Daqing, 2008, 27(1): 78-82.
[9] 张林, 贾永禄, 张福祥, 等. 考虑二次压力梯度非线性渗流三区复合油藏模型分析[J]. 大庆石油学院学报, 2011, 35(5): 54-59. Zhang Lin, Jia Yonglu, Zhang Fuxiang, et al. Analysis of considering quadratic pressure gradient nonlinear percolation in three-zone composite reservoir[J]. Journal of Daqing Petroleum Institute, 2011, 35(5): 54-59.
[10] 刘慧卿, 李景梅, 赵鹏, 等. 热力采油井现代试井分析方法研究[J]. 石油钻探技术, 2003, 31(4): 4-6. Liu Huiqing, Li Jingmei, Zhao Peng, et al. Study on modern well test analysis methods for thermal recovery wells[J]. Petroleum Drilling Techniques, 2003, 31(4): 4-6.
[11] Onyekonwu M O. Interpretation of in-situ combustion thermal oil recovery falloff' tests[D]. Stanford: Stanford University, 1985.
[12] Tabrizy V A. Investigated miscible CO2 flooding for enhancing oil recovery in wettability altered chalk and sandstone rocks[D]. Stavanger: University of Stavanger, 2012.
[13] Holm L W, Josendel V A. Mechanisms of oil displacement by carbon dioxide[J]. Journal of Petroleum Technology, 1974, 26(12): 1427-1436.
[14] Issaka M, Ambastha A K. An improved three-region composite reservoir model for thermal recovery well test analysis[C]. PETSOC Annual Technical Meeting, Calgary, Alberta, Canada, June 8-11, 1997.
[15] 宋考平, 王雷, 计秉玉. 非牛顿－牛顿复合油藏渗流试井解释方法[J]. 石油学报, 1996, 17(1): 82-86. Song Kaoping, Wang Lei, Ji Bingyu. Well test analysis of a compound reservoir with non-newtonian and newtonian fluid flow[J]. Atca Petrolei Sinica, 1996,17 (1): 82-86.
[16] 宋考平, 祝俊峰, 刘泽俊, 等. 多区复合油藏非牛顿幂律流体试井解释[J]. 石油学报, 1997, 18(2): 81-86. Song Kaoping, Zhu Junfeng, Liu Zejun, et al. Well test analysis for a compound reservoir with non-newtonian power law fluid flow[J]. Atca Petrolei Sinica, 1997, 18(2): 81-86.
