Numerical Well Test Interpretation of Massive Multistage Fractured Horizontal Wells in Tight Oil Reservoirs and Effect of Permeability of Exterior Region on Well Test Curves
-
摘要: 多段压裂水平井试井解释能对压裂规模、主裂缝半长等参数进行有效评价，为产能评价等提供基础参数.然而当前缺少针对实际井例数据进行的深入分析.基于PEBI（perpendicular bisector）网格对油水两相渗流方程进行数值求解，利用无限导流的主裂缝与分支缝导致的区域渗透率扩大来描述SRV（stimulated reservoir volume），建立了致密油大规模多段压裂水平井瞬态压力分析方法.基于大庆油田的实测数据进行解释并进行渗透率敏感性分析，研究了复合区域下的参数调整方法.研究表明，当外区渗透率变小时，早期的压力导数变小，后期的压力导数变大，而不是所有的压力导数值都变大.压力导数由小到大的转折点时间与渗透率大小相关.因而，当前期的压力导数曲线拟合效果好、后期的压力导数拟合效果差时，不能仅通过调整外区的渗透率来拟合，还应调整其他参数.另外，大庆致密油藏多段压裂水平井实测曲线中的启动压力梯度特征不明显.相关研究结果对致密油大规模多段压裂水平井实测数据解释具有重要的指导意义.Abstract: Numerical well test interpretation of massive multistage fractured horizontal wells can be used for the fracturing effect evaluation, which is very important for productivity evaluation. However, few field case studies have been conducted. Numerical solution of oil-water two-phase flow based on PEBI grid and description of stimulated reservoir volume (SRV) by main fractures with infinite conductivity and improved permeability of the region with minor fractures are used in combination to interpret the transient pressure of massive multistage fractured horizontal wells in tight oil reservoirs in Daqing oilfield. The interpretation and sensitivity analysis of permeability of exterior region show that the value of pressure derivative becomes smaller at early time and becomes larger at late time when the permeability of exterior region decreases, compared with pressure derivative without permeability modification, which indicates a turning point on the curves of pressure derivative. Prior to the turning point, the pressure derivative with smaller permeability in exterior region is relatively smaller, while after the point, the pressure derivative is larger. The time of appearance of the turning point is related to the magnitude of permeability between those of exterior and interior regions. Therefore, when good fitting of pressure derivative curves achieves at early time and bad fitting of pressure derivative curves at late time, adjustment of permeability of exterior region cannot wholly improve the fitting effect, and other parameters need to be adjusted to improve the fitting. This study can facilitate future transient pressure analysis for massive multistage fractured horizontal wells in tight oil reservoirs.
-
图 1 等效主裂及渗透率提高的区域示意
Fig. 1. Schematic of equivalent main fracture and permeability improved region
图 4 所解释的油藏示意
a.油藏面积约为4 640 m×3 900 m；b.油藏厚度为1.7 m
Fig. 4. The sketch of the interpreted reservoir
图 6 不同K1与K2组合下的瞬态压力响应特征
a.全局图；b.压力导数曲线局部放大
Fig. 6. Characteristics of pressure transient response under different combination of K1 and K2
图 7 外区渗透率K2=4.8 mD与K2=0.8 mD的瞬态压力曲线对比
a.全局图；b.对方形框的局部放大
Fig. 7. Comparison of pressure transient curves between permeability of exterior region K2=4.8 mD and K2=0.8 mD
图 8 外区渗透率K2=0.8 mD与K2=0.1 mD的瞬态压力曲线对比
a.全局图；b.对方形框的局部放大
Fig. 8. Comparison of pressure transient curves between permeability of exterior region K2=4.8 mD and K2=0.1 mD
图 9 外区渗透率K2=0.01 mD与K2=0.1 mD的瞬态压力曲线对比
a.外区渗透率K2对瞬态压力响应的影响；b.局部放大
Fig. 9. Comparison of pressure transient curves between permeability of exterior region K2=0.01 mD and K2=0.1 mD
图 10 可通过调整外区渗透率来拟合的情形
Fig. 10. Enable to fit by adjusting permeability of exterior region
表 1 所解释油藏的相关参数
Table 1. The related parameters
名称 数值 气藏大小(m×m) 4 640×3 900 初始压力(MPa) 13.15 初始水饱和度 0.633 气藏厚度(m) 1.7 岩石压缩性(1/MPa) 0.000 58 油相粘度(mPa·s) 0.6 油相体积系数 1 油相粘度(mPa·s) 1.45 油相体积系数 1.23 孔隙度 0.139 SRV面积(m2) 115 716 水平井表皮因子 0 水平井井储(m3/MPa) 25 
下载: 导出CSV
表 2 每种情形的裂缝半长
Table 2. Fracture half-length of each case
算例 裂缝周围区域的渗透率
K1(mD)其他区域的渗透率
K2(mD)解释的结果 4.8 0.8 敏感性分析算例1 4.8 0.1 敏感性分析算例2 4.8 0.01 敏感性分析算例3 4.8 4.8
下载: 导出CSV
-
Brown, M., Ozkan, E., Raghavan, R., et al., 2009.Practical Solutions for Pressure-Transient Responses of Fractured Horizontal Wells in Unconventional Shale Reservoirs.SPE Reservoir Evaluation & Engineering, 14(6):663-676.doi: 10.2118/125043-PA Cai, J.C., 2014.A Fractal Approach to Low Velocity Non-Darcy Flow in a Low Permeability Porous Medium.Chinese Physics B, 23(4):044701.doi: 10.1088/1674-1056/23/4/044701 Cho, Y., Ozkan, E., Apaydin, O.G., 2013.Pressure-Dependent Natural-Fracture Permeability in Shale and Its Effect on Shale-Gas Well Production.SPE Reservoir Evaluation & Engineering, 16(2):216-228.doi: 10.2118/159801-PA Cipolla, C.L., Lolon, E.P., Erdle, J.C., et al., 2010.Reservoir Modeling in Shale-Gas Reservoirs.SPE Reservoir Evaluation & Engineering, 13(4):638-653.doi: 10.2118/125530-pa Clarkson, C.R., Beierle, J.J., 2011.Integration of Microseismic and Other Post-Fracture Surveillance with Production Analysis:A Tight Gas Study.Journal of Natural Gas Science and Engineering, 3(2):382-401.doi: 10.1016/j.jngse.2011.03.003 Clarkson, C.R., Pedersen, P.K., 2010.Tight Oil Production Analysis:Adaptation of Existing Rate-Transient Analysis Techniques.Canadian Unconventional Resources and International Petroleum Conference, Calgary.doi:10.2118/137352-ms Deng, Y.E., Liu, C.Q., 2001.Mathematical Model of Nonlinear Flow Law in Low Permeability Porous Media and Its Application.Acta Petrolei Sinica, 22(4):72-77 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-SYXB200104018.htm Guo, Y.C., Song, Y., Pang, X.Q., et al., 2016.Characteristics and Genetic Mechanism of Near Source Accumulated Accumulation for Continuous Type Tight Sand Gas.Earth Science, 41(3):433-440 (in Chinese with English abstract). http://www.en.cnki.com.cn/Article_en/CJFDTotal-DQKX201603009.htm Li, A.F., Liu, M., Zhang, S.H., et al., 2008.Experimental Study on the Percolation Characteristic of Extra Low-Permeability Reservoir.Journal of Xi'an Shiyou University (Natural Science Edition), 23(2):35-39 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-XASY200802011.htm Li, C.L., Yang, Y.Q., 2008.There is not a Starting Pressure Gradient in Low-Permeability Reservoirs at All.Journal of Southwest Petroleum University (Science & Technology Edition), 30(3):167-170 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-XNSY200803046.htm Li, D.L., Xu, C.Y., Wang, J.Y.L., et al., 2014.Effect of Knudsen Diffusion and Langmuir Adsorption on Pressure Transient Response in Shale Gas Reservoir.Journal of Petroleum Science and Engineering, 124:146-154.doi: 10.1016/j.petrol.2014.10.012 Li, D.L., Yang, J.H., Zha, W.S., et al., 2015.Unsuitability of Using Superposition Principle to Solve Equation Incorporating with Threshold Pressure Gradient.Journal of Southwest Petroleum University (Science & Technology Edition), 37(4):81-89 (in Chinese with English abstract). http://zk.swpuxb.com/EN/Y2015/V37/I4/81 Li, D.L., Zha, W.S., 2013.Theory and Method of Numerical Welltest.China Petroleum Industry Press, Beijing (in Chinese). Li, D.L., Zhang, L.J., Wang, J.Y.L., et al., 2016a.Effect of Adsorption and Permeability Correction on Transient Pressures in Organic Rich Gas Reservoirs:Vertical and Hydraulically Fractured Horizontal Wells.Journal of Natural Gas Science and Engineering, 31:214-225.doi: 10.1016/j.jngse.2016.02.033 Li, D.L., Zha, W.S., Liu, S.F., et al., 2016b.Pressure Transient Analysis of Low Permeability Reservoir with Pseudo Threshold Pressure Gradient.Journal of Petroleum Science and Engineering, 147:308-316.doi: 10.1016/j.petrol.2016.05.036 Li, S.S., Duan, Y.G., Chen, W., et al., 2006.Well Testing Analysis of Fractured Horizontal Well.Petroleum Geology & Oilfield Development in Daqing, 25(3):67-69, 78 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-DQSK200603026.htm Medeiros, F., Kurtoglu, B., Ozkan, E., et al., 2010.Analysis of Production Data from Hydraulically Fractured Horizontal Wells in Shale Reservoirs.SPE Reservoir Evaluation & Engineering, 13(3):559-568.doi: 10.2118/110848-pa Nobakht, M., Clarkson, C.R., 2011.A New Analytical Method for Analyzing Production Data from Shale Gas Reservoirs Exhibiting Linear Flow:Constant Rate Production.North American Unconventional Gas Conference and Exhibition, Woodlands.doi:10.2118/143990-ms Ozkan, E., Brown, M.L., Raghavan, R., et al., 2011.Comparison of Fractured-Horizontal-Well Performance in Tight Sand and Shale Reservoirs.SPE Reservoir Evaluation & Engineering, 14(2):248-259.doi: 10.2118/121290-pa Pascal, H., 1981.Nonsteady Flow through Porous Media in the Presence of a Threshold Gradient.Acta Mechanica, 39(3-4):207-224.doi: 10.1007/bf01170343 Prada, A., Civan, F., 1999.Modification of Darcy's Law for the Threshold Pressure Gradient.Journal of Petroleum Science and Engineering, 22(4):237-240.doi: 10.1016/S0920-4105(98)00083-7 Ren, D.Z., Sun, W., Huang, H., et al., 2016.Formation Mechanism of Chang 6 Tight Sandstone Reservoir in Jiyuan Oilfield, Ordos Basin.Earth Science, 41(10):1735-1744 (in Chinese with English abstract). http://www.en.cnki.com.cn/Article_en/CJFDTotal-DQKX201610009.htm Wang, B.C., Jia, Y.L., Li, Y.Q., et al., 2013.A New Solution of Well Test Model for Multistage Fractured Horizontal Wells.Acta Petrolei Sinica, 36(6):1150-1156 (in Chinese with English abstract). http://www.syxb-cps.com.cn/EN/Y2013/V34/I6/1150 Yang, Y.F., Wang, C.C., Yao, J., et al., 2016.A New Method for Microscopic Pore Structure Analysis in Shale Matrix.Earth Science, 41(6):1067-1073 (in Chinese with English abstract). http://www.sciencedirect.com/science/article/pii/S0016236116303118 Yao, J., Yin, X.X., Fan, D.Y., et al., 2011.Trilinear-Flow Well Test Model of Fractured Horizontal Well in Low Permeability Reservoir.Well Testing, 20(5):1-5 (in Chinese with English abstract). https://www.onepetro.org/conference-paper/SPE-170971-MS?sort=&start=0&q=gas+trilinear+flow&from_year=&peer_reviewed=&published_between=&fromSearchResults=true&to_year=&rows=10 邓英尔, 刘慈群, 2001.低渗油藏非线性渗流规律数学模型及其应用.石油学报, 22(4): 72-77. doi: 10.7623/syxb200104014 郭迎春, 宋岩, 庞雄奇, 等, 2016.连续型致密砂岩气近源累计聚集的特征及成因机制.地球科学, 41(3): 433-440. doi: 10.11764/j.issn.1672-1926.2016.03.0433 李爱芬, 刘敏, 张少辉, 等, 2008.特低渗透油藏渗流特征实验研究.西安石油大学学报(自然科学版), 23(2): 35-39. http://cdmd.cnki.com.cn/Article/CDMD-10220-2004050749.htm 李传亮, 杨永全, 2008.启动压力其实并不存在.西南石油大学学报(自然科学版), 30(3): 167-170. http://www.cnki.com.cn/Article/CJFDTOTAL-XNSY200803046.htm 李道伦, 杨景海, 查文舒, 等, 2015.叠加原理不能求解含启动压力梯度渗流方程.西南石油大学学报(自然科学版), 37(4): 81-89. doi: 10.11885/j.issn.1674-5086.2014.11.28.01 李道伦, 查文舒, 2013.数值试井理论与方法.北京:石油工业出版社. 李树松, 段永刚, 陈伟, 等, 2006.压裂水平井多裂缝系统的试井分析.大庆石油地质与开发, 25(3): 67-69, 78. http://www.cnki.com.cn/Article/CJFDTOTAL-DQSK200603026.htm 任大忠, 孙卫, 黄海, 等, 2016.鄂尔多斯盆地姬塬油田长致密砂岩储层成因机理.地球科学, 41(10): 1735-1744. http://www.earth-science.net/WebPage/Article.aspx?id=3375 王本成, 贾永禄, 李友全, 等, 2013.多段压裂水平井试井模型求解新方法.石油学报, 36(6): 1150-1156. doi: 10.7623/syxb201306015 杨永飞, 王晨晨, 姚军, 等, 2016.页岩基质微观孔隙结构分析新方法.地球科学, 41(6): 1067-1073. doi: 10.11764/j.issn.1672-1926.2016.06.1067 姚军, 殷修杏, 樊冬艳, 等, 2011.低渗透油藏的压裂水平井三线性流试井模型.油气井测试, 20(5): 1-5. http://www.cnki.com.cn/Article/CJFDTOTAL-YQJC201105002.htm -
点击查看大图
图(11) / 表(2)
计量
- 文章访问数: 5903
- HTML全文浏览量: 2656
- PDF下载量: 37
- 被引次数: 0
