Spontaneous Imbibition Characteristics and Influencing Factors of Chang 7 Shale Oil Reservoirs in Longdong Area, Ordos Basin
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摘要: 自发渗吸存在于页岩油藏体积压裂和注水开发等多个关键阶段,是影响页岩油产能的重要因素之一,厘清渗吸特征及影响因素对提高页岩油采收率有重要意义. 对鄂尔多斯盆地长7段不同源储配置关系的页岩油储层岩心开展自发渗吸实验,结合核磁共振技术监测流体运移过程,分析储层物性及孔隙结构对页岩油储层自发渗吸的影响机制,明确源储配置关系对渗吸的控制作用. 长7段页岩油储层中储夹源型渗吸体积分数均值为33.84%,源储互层型为25.98%;储夹源型渗吸阶段斜率均值为0.359,源储互层型均值为0.302;渗吸过程中核磁共振横向弛豫时间小于10 ms的孔隙占比高;渗吸体积分数与润湿性、储层品质因子及孔喉比相关性较好. 长7段页岩油储层储夹源型配置关系渗吸能力优于源储互层型;储层渗吸能力主要由润湿性、储层品质因子及孔喉比控制.Abstract: Spontaneous imbibition exists in many key stages such as volume fracturing and water injection development in shale reservoirs, which is one of the important factors affecting shale oil productivity. Clarifying the characteristics of imbibition and influencing factors is of great significance to improve the recovery of shale oil. In this paper, spontaneous imbibition experiments were carried out on shale oil reservoirs samples with different source⁃reservoir configuration relationships in Chang 7 member of Ordos Basin. Combined with NMR technology, fluid migration process was monitored, and the influence mechanism of reservoir physical properties and pore structure on spontaneous imbibition of shale oil reservoirs was analyzed, so as to clarify the control effect of source⁃reservoir configuration relationship on imbibition. The average volume fraction of source-type imbibition in Chang 7 member is 33.84 %, and the source-reservoir interbed type is 25.98 %. The average slope of the source⁃type suction stage is 0.359, and the average of the source⁃reservoir interlayer type is 0.302. The proportion of pores with NMR transverse relaxation time less than 10 ms in the imbibition process is high; imbibition volume fraction has good correlation with wettability, reservoir quality factor and pore throat ratio. The permeability of source⁃source configuration relationship of Chang 7 shale oil reservoir is better than that of source⁃reservoir interbed; reservoir imbibition capacity is mainly controlled by wettability, reservoir quality factor and pore throat ratio.
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图 1 鄂尔多斯盆地构造单元划分及研究区位置
Fig. 1. The division of structural units and the location of the study area in the Ordos Basin
表 1 样品基本物性参数
Table 1. Basic physical property parameters of samples
源储配置关系 编号 深度(m) 长度(cm) 直径(cm) 孔隙度(%) 渗透率(mD) 润湿角(°) 源储互层型 8 1 791.3 5.689 2.509 10.32 0.097 36.8 16 1 976.9 5.390 2.523 9.25 0.039 35.0 储夹源型 11 1 768.0 3.473 2.522 11.64 0.105 33.3 13 1 957.5 5.103 2.515 13.69 0.106 41.5 14 1 964.5 5.887 2.514 12.47 0.065 39.2 17 1 514.2 6.291 2.523 8.13 0.126 28.4 18 1 980.0 6.251 2.523 7.92 0.056 38.4 表 2 样品矿物组成
Table 2. Mineral composition of the sample
编号 石英(%) 钾长石(%) 斜长石(%) 方解石(%) 白云石(%) 菱铁矿(%) 白云母(%) 黏土含量(%) 8 60.2 1.1 17.4 2.4 6.1 - 1.0 11.8 11 57.6 6.4 14.5 0.2 4.1 2.8 2.8 11.6 13 61.2 1.5 11.1 2.3 9.0 2.5 2.1 10.3 14 52.9 3.8 9.5 0.5 5.5 2.0 2.7 22.2 16 63.1 2.8 14.4 0.8 5.3 1.4 3.0 9.2 17 60.7 11.9 12.2 0.9 2.5 - 1.9 9.7 18 60.2 4.6 9.9 0.3 3.9 1.5 1.6 18.0 均值 59.4 4.6 12.7 1.1 5.2 2.0 2.2 13.3 表 3 样品孔隙结构参数
Table 3. Pore structure property parameters of samples
编号 平均孔隙半径(μm) 配位数 平均喉道半径(μm) 孔喉比 8 4.17 1.18 3.730 1.12 11 2.47 1.32 2.090 1.18 13 2.67 0.89 2.359 1.13 14 3.92 1.18 3.470 1.13 16 2.32 0.63 1.980 1.17 17 2.74 0.77 2.090 1.31 18 2.62 0.87 1.869 1.41 表 4 渗吸体积分数及无量纲渗吸质量
Table 4. Imbibition volume fraction and dimensionless imbibition mass
编号 渗吸体积分数(%) 无量纲渗吸质量 8 27.67 0.012 8 11 25.81 0.014 8 13 22.43 0.014 7 14 26.33 0.015 6 16 24.28 0.010 2 17 39.50 0.014 3 18 55.15 0.019 3 表 5 样品渗吸体积分数及储层品质因子
Table 5. The imbibition volume fraction and reservoir quality factor
编号 渗吸体积分数 储层品质因子(mD0.5) 8 0.276 7 0.304 4 11 0.258 1 0.298 1 13 0.224 3 0.276 6 14 0.263 3 0.226 5 16 0.242 8 0.202 6 17 0.395 0 0.390 9 18 0.551 5 0.264 4 -
[1] Amaefule, J.O., Altunbay, M., Tiab, D., et al., 1993. Enhanced Reservoir Description: Using Core and Log Data to Identify Hydraulic (Flow) Units and Predict Permeability in Uncored Intervals/Wells. SPE Annual Technical Conference and Exhibition. Texas. https://doi.org/10.2118/26436-MS [2] Austad, T., Standnes, D. C., 2003. Spontaneous Imbibition of Water into Oil-Wet Carbonates. Journal of Petroleum Science and Engineering, 39(3/4): 363-376. https://doi.org/10.1016/s0920-4105(03)00075-5 [3] Blunt, M. J., Bijeljic, B., Dong, H., et al., 2013. Pore-Scale Imaging and Modelling. Advances in Water Resources, 51(2-3): 197-216. https://doi.org/10.1016/j.advwatres.2012.03.003 [4] Cai, J.C., 2021. Some Key Issues and Thoughts on Spontaneous Imbibition in Porous Media. Chinese Journal of Computational Physics, 38(5): 505-512(in Chinese with English abstract). [5] Cai, J.C., Perfect, E., Cheng, C.L., et al., 2014. Generalized Modeling of Spontaneous Imbibition Based on Hagen-Poiseuille Flow in Tortuous Capillaries with Variably Shaped Apertures. Langmuir, 30(18): 5142-5151. https://doi.org/10.1021/la5007204 [6] Dang, H.L., Wang, X.F., Cui, P.X., et al., 2020. Research on the Characteristics of Spontaneous Imbibition Oil Displacement with the Low Permeability Tight-Sandstone Oil Reservoir Using the Nuclear Magnetic Resonance (NMR) Technology. Progress in Geophysics, 35(5): 1759-1769(in Chinese with English abstract). [7] Diao, Z. H., Li, S., Liu, W., et al., 2021. Numerical Study of the Effect of Tortuosity and Mixed Wettability on Spontaneous Imbibition in Heterogeneous Porous Media. Capillarity, 4(3): 50-62. https://doi.org/10.46690/capi.2021.03.02 [8] Dong, D.P., Li, B.H., Yuan, S.W., et al., 2021. Spontaneous Imbibition Characteristics of the Low-Permeability Water-Wet Core Based on the NMR Test. Petroleum Geology & Oilfield Development in Daqing, 40(2): 60-65(in Chinese with English abstract). [9] Fu, J. H., Li, S. X., Niu, X. B., et al., 2020. Geological Characteristics and Exploration of Shale Oil in Chang 7 Member of Triassic Yanchang Formation, Ordos Basin, NW China. Petroleum Exploration and Development, 47(5): 931-945. https://doi.org/10.1016/s1876-3804(20)60107-0 [10] Gao, Z. Y., Fan, Y. P., Xuan, Q. X., et al., 2020. A Review of Shale Pore Structure Evolution Characteristics with Increasing Thermal Maturities. Advances in Geo-Energy Research, 4(3): 247-259. https://doi.org/10.46690/ager.2020.03.03 [11] Gu, X. Y., Pu, C. S., Huang, H., et al., 2017. Micro-Influencing Mechanism of Permeability on Spontaneous Imbibition Recovery for Tight Sandstone Reservoirs. Petroleum Exploration and Development, 44(6): 1003-1009. https://doi.org/10.1016/s1876-3804(17)30112-x [12] Guo, J. C., Li, M., Chen, C., et al., 2020. Experimental Investigation of Spontaneous Imbibition in Tight Sandstone Reservoirs. Journal of Petroleum Science and Engineering, 193(3): 107395. https://doi.org/10.1016/j.petrol.2020.107395 [13] Hu, Q. H., Ewing, R. P., Dultz, S., 2012. Low Pore Connectivity in Natural Rock. Journal of Contaminant Hydrology, 133(B10): 76-83. https://doi.org/10.1016/j.jconhyd.2012.03.006 [14] Huang, R.Z., Jiang, Z.X., Gao, Z.Y., et al., 2017. Effect of Composition and Structural Characteristics on Spontaneous Imbibition of Shale Reservoir. Petroleum Geology and Recovery Efficiency, 24(1): 111-115(in Chinese with English abstract). [15] Jia, C. Z., Zheng, M., Zhang, Y. F., 2012. Unconventional Hydrocarbon Resources in China and the Prospect of Exploration and Development. Petroleum Exploration and Development, 39(2): 139-146. https://doi.org/10.1016/s1876-3804(12)60026-3 [16] Li, C.S., Zhang, W.S., Lei, Y., 2021. Characteristics and Controlling Factors of Oil Accumulation in Chang 9 Member in Longdong Area, Ordos Basin. Earth Science, 46(10): 3560-3574(in Chinese with English abstract). [17] Li, C. X., Singh, H., Cai, J. C., 2019. Spontaneous Imbibition in Shale: A Review of Recent Advances. Capillarity, 2(2): 17-32. https://doi.org/10.26804/capi.2019.02.01 [18] Liu, H. L., Yang, Y. Y., Wang, F. Q., et al., 2018. Micro Pore and Throat Characteristics and Origin of Tight Sandstone Reservoirs: A Case Study of the Triassic Chang 6 and Chang 8 Members in Longdong Area, Ordos Basin, NW China. Petroleum Exploration and Development, 45(2): 239-250. https://doi.org/10.1016/s1876-3804(18)30027-2 [19] Lyu, C., Ning, Z. F., Chen, M. Q., et al., 2019. Experimental Study of Boundary Condition Effects on Spontaneous Imbibition in Tight Sandstones. Fuel, 235(4): 374-383. https://doi.org/10.1016/j.fuel.2018.07.119 [20] Shen, Y. H., Ge, H. K., Li, C. X., et al., 2016. Water Imbibition of Shale and its Potential Influence on Shale Gas Recovery: a Comparative Study of Marine and Continental Shale Formations. Journal of Natural Gas Science and Engineering, 35(3): 1121-1128. https://doi.org/10.1016/j.jngse.2016.09.053 [21] Umeobi, H. I., Li, Q., Xu, L., et al., 2021. NMR Investigation of Brine Imbibition Dynamics in Pores of Tight Sandstones under Different Boundary Conditions. Energy & Fuels, 35(19): 15856-15866. https://doi.org/10.1021/acs.energyfuels.1c01417 [22] Wang, F.W., Chen, D.X., Xie, G. j., et al., 2022. Differential Enrichment Mechanism of Tight Sandstone Oil under the Control of the Source-Rreservoir Structures of Member 7 of Yanchang Formation in Qingcheng Area, Ordos Basin. Acta Pctrolei Sinica, 43(7): 941-956, 976(in Chinese with English abstract). [23] Wang, X. J., Wang, M., Li, Y., et al., 2021. Shale Pore Connectivity and Influencing Factors Based on Spontaneous Imbibition Combined with a Nuclear Magnetic Resonance Experiment. Marine and Petroleum Geology, 132: 105239. https://doi.org/10.1016/j.marpetgeo.2021.105239 [24] Wu, Z.Y., Gao, Z.W., Ma, S.W., et al., 2021. Preliminary Study on Imbibition and Oil Displacement of Chang 7 Shale Oil in Ordos Basin. Natural Gas Geoscience, 32(2): 1874-1879(in Chinese with English abstract). [25] Xia, Y. X., Tian, Z. H., Xu, S., et al., 2021. Effects of Microstructural and Petrophysical Properties on Spontaneous Imbibition in Tight Sandstone Reservoirs. Journal of Natural Gas Science and Engineering, 96: 104225. https://doi.org/10.1016/j.jngse.2021.104225 [26] Xu, X.Y., Wang, W.T., 2020. The Recognition of Potential Fault Zone in Ordos Basin and Its Reservoir Control. Earth Science, 45(5): 1754-1768(in Chinese with English abstract). [27] Yang, L., Ge, H. K., Shi, X., et al., 2016. The Effect of Microstructure and Rock Mineralogy on Water Imbibition Characteristics in Tight Reservoirs. Journal of Natural Gas Science and Engineering, 34(2): 1461-1471. https://doi.org/10.1016/j.jngse.2016.01.002 [28] Yang, Z.F., Zeng, J.H., Feng, X., et al., 2015. Effects of Source-Reservoir Lithologic Assemblage on Tight Oil Accumulation: A Case Study of Yanchang Chang-7 Member in Ordos Basin. Xinjiang Petroleum Geology, 36(4): 383-393(in Chinese with English abstract). [29] Yao, J.L., Zeng J.H., Luo, A.X., et al., 2019. Controlling Effect of Source-Reservoir Structure in Tight Reservoir on Oil-Bearing Property: A Case Study of Chang-6~Chang-8 Members in Heshui Area of Ordos Basin, China. Journal of Earth Sciences & Environment, 41(3): 267-280(in Chinese with English abstract). [30] You, Y., Niu, X.B., Feng, S.B., et al., 2014. Study of pore features in Chang7 Tight Oil Reservoir, Yanchang Layer, Ordos Basin. Journal of China University of Petroleum (Edition of Natural Science), 38(6): 18-23(in Chinese with English abstract). [31] Yu, R.A., Zhu, Q., Wen, S.B., et al., 2020. Tectonic Setting and Provenance Analysis of Zhiluo Formation and Stone of Tarangaole Area in the Ordos Basin. Earth Science, 45(5): 1754-1768(in Chinese with English abstract). [32] 蔡建超, 2021. 多孔介质自发渗吸关键问题与思考. 计算物理, 38(5): 505-512. https://www.cnki.com.cn/Article/CJFDTOTAL-JSWL202105001.htm [33] 党海龙, 王小锋, 崔鹏兴, 等, 2020. 基于核磁共振技术的低渗透致密砂岩油藏渗吸驱油特征研究. 地球物理学进展, 35(5): 1759-1769. https://www.cnki.com.cn/Article/CJFDTOTAL-DQWJ202005016.htm [34] 董大鹏, 李斌会, 苑盛旺, 等, 2021. 基于核磁共振测试的低渗亲水岩心静态渗吸特征. 大庆石油地质与开发, 40(2): 60-65. https://www.cnki.com.cn/Article/CJFDTOTAL-DQSK202102007.htm [35] 黄睿哲, 姜振学, 高之业, 等, 2017. 页岩储层组构特征对自发渗吸的影响. 油气地质与采收率, 24(1): 111-115. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS201701019.htm [36] 李程善, 张文选, 雷宇, 等, 2021. 鄂尔多斯盆地陇东地区长9油层组砂体成因与油气差异分布. 地球科学, 46(10): 3560-3574. doi: 10.3799/dqkx.2021.007 [37] 王福伟, 陈冬霞, 解广杰, 等. 2022. 鄂尔多斯盆地庆城地区延长组7段源-储结构控制下致密砂岩油的差异富集机制. 石油学报, 43(7): 941-956, 976. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202207005.htm [38] 吴志宇, 高占武, 麻书玮, 等, 2021. 鄂尔多斯盆地长7段页岩油渗吸驱油现象初探. 天然气地球科学, 32(12): 1874-1879. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX202112013.htm [39] 徐兴雨, 王伟锋, 2020. 鄂尔多斯盆地隐性断裂识别及其控藏作用. 地球科学, 45(5): 1754-1768 doi: 10.3799/dqkx.2019.175 [40] 杨智峰, 曾溅辉, 冯枭, 等, 2015. 源储岩性组合对致密油聚集的影响——以鄂尔多斯盆地延长组长7段为例. 新疆石油地质, 36(4): 383-393. https://www.cnki.com.cn/Article/CJFDTOTAL-XJSD201504004.htm [41] 姚泾利, 曾溅辉, 罗安湘, 等, 2019. 致密储层源储结构对储层含油性的控制作用——以鄂尔多斯盆地合水地区长6~长8段为例. 地球科学与环境学报, 41(3): 267-280. doi: 10.3969/j.issn.1672-6561.2019.03.002 [42] 尤源, 牛小兵, 冯胜斌, 等, 2014. 延长组页岩油储层微观孔隙特征研究. 中国石油大学学报(自然科学版), 38(6): 18-23. doi: 10.3969/j.issn.1673-5005.2014.06.003 [43] 俞礽安, 朱强, 文思博, 等, 2020. 鄂尔多斯盆地塔然高勒地区直罗组砂岩源区构造背景与物源分析. 地球科学, 45(3): 829-843. doi: 10.3799/dqkx.2020.001