Key Technology of Shale Oil Sweet Spot Evaluation and Sweet Spot Type Division in Fengcheng Formation of Mahu Sag
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摘要: 玛湖凹陷风城组页岩油是准噶尔盆地油气勘探的新领域,明确其优质“甜点”发育段,对试油层位选择及水平井的部署具有重要意义.从页岩油评价中的2个关键地质工程参数——游离油、脆性指数入手,以系统实验为基础,开展了玛湖风城组页岩油游离油、脆性指数的测井评价方法研究,并分析了2个参数对产量的影响,建立了产量潜力指数计算模型,形成了“甜点”分类方法.结果表明:(1)二维核磁共振谱(T2,T1)可以有效区分可动水、游离油、吸附油(T1/T2:可动水 < 游离油 < 吸附油),风城组页岩油层游离油孔隙度低,主要为0.5%~3.0%;(2)页岩油层脆性好,脆性指数在70%以上,但杨氏模量大,水力压裂起裂难度较大;(3)根据产能潜力指数分为三类甜点,纵向上三类甜点交互叠合发育,可以优选出2套优质甜点集中发育段.建立的页岩油甜点评价关键技术为风城组页岩油试油选层及水平井目标层选择提供了重要依据,可为国内其他陆相盆地页岩油甜点评价提供借鉴.Abstract: Mahu Fengcheng Formation shale oil is a new field of oil and gas exploration in Junggar Basin. Clarifying its high-quality "sweet spot" development section is of great significance to the oil test horizon and the deployment of horizontal wells. Starting with two key geological engineering parameters in shale oil evaluation: free oil and brittleness index, and based on the systematic experimental site, in this paper it studies the logging evaluation method of free oil and brittleness index of shale oil in Mahu Fengcheng Formation, analyzes the influence of the two parameters on production, establishes the calculation model of production potential index, and forms the "sweet spot" classification method. The research shows that: (1) (T2, T1) 2D NMR method can effectively distinguish movable water, free oil and adsorbed oil (T1/T2: movable water < free oil < adsorbed oil). The porosity of free oil in shale reservoir of Fengcheng Formation is low, mainly 0.5%-3.0%. (2) Shale oil layer has good brittleness, and the brittleness index is more than 70%, but the Young's modulus is large, so it is difficult to start fracturing by hydraulic fracturing. (3) According to the productivity potential index, it is divided into three types of sweet spots. Vertically, the three types of sweet spots are overlapped and developed, and three sets of high-quality sweet spots can be selected. The key technology of shale oil sweet spot evaluation proposed in the research provides an important basis for shale oil testing and layer selection of Fengcheng Formation and target layer selection of horizontal wells. This technical method can provide a reference for shale oil sweet spot evaluation in other continental basins in China.
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Key words:
- Fengcheng Formation /
- shale oil /
- free oil /
- brittleness index /
- sweet spot evaluation /
- geophysics
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表 1 实验样品的规格
Table 1. Specifications of experimental samples
编号 重量
(g)平均长度(cm) 平均直径(cm) 体积
(cm3)井名 1-1 56.46 4.57 2.51 22.67 MY1 1-2 76.63 5.69 2.50 28.10 MY1 1-3 72.21 5.60 2.51 27.71 MY1 1-4 51.66 4.31 2.51 21.39 MY1 1-5 57.40 4.59 2.51 22.76 MY1 表 2 三轴抗压实验力学参数
Table 2. Mechanical parameters of triaxial compression test
井号 深度
(m)围压
(MPa)峰值压力
(MPa)静态杨氏模量
(GPa)静态
泊松比弹性形变
(10‒3 m)塑性形变
(10‒3 m)脆性指数
(%)粘土矿物
(%)方解石+白云石(%) MY1 4 715.07 55.0 530.3 60.0 0.22 13.20 5.13 72.0 2.8 20.9 MY1 4 717.40 55.0 450.8 56.4 0.40 11.85 4.38 73.0 2.5 64.6 MY1 4 731.65 55.0 610.8 72.0 0.29 12.92 0.82 94.0 5.5 34.2 MY1 4 733.79 55.0 465.1 64.0 0.37 10.41 0.32 97.0 3.7 59.3 MY1 4 747.42 56.0 403.7 53.5 0.38 11.35 4.87 70.0 1.8 60.9 MY1 4 755.60 56.0 410.0 50.0 0.39 12.25 4.31 74.0 5.3 54.1 MY1 4 758.23 56.0 723.8 67.4 0.36 16.49 1.63 91.0 1.6 47.0 MY1 4 780.23 57.0 768.0 70.5 0.35 16.52 0.17 99.0 2.9 18.8 MY1 4 792.17 57.0 662.1 73.1 0.30 13.70 1.69 89.0 6.0 26.4 MY1 4 810.43 57.0 734.1 70.5 0.20 15.80 1.19 93.0 3.6 52.8 表 3 MY1井试油层段相关参数
Table 3. Statistics of relevant parameters of Well MY1 test interval
级数 射孔簇 游离油孔隙度
(%)脆性指数
(%)六次平均产量(t) 7 7-2 3.4 77.6 1.36 7 7-1 0.3 83.5 0.24 6 6-3 1.3 88.1 0.64 6 6-2 0.1 86.8 0.35 6 6-1 0.3 88.2 0.36 4 4-2 1.9 95.7 0.14 4 4-1 4.1 94.0 1.66 3 3-2 0.7 95.9 0.50 3 3-1 2.3 98.9 0.77 2 2-2 1.7 99.1 0.98 2 2-1 1.3 99.0 0.27 1 1-2 0.2 73.8 0.43 1 1-1 1.1 76.8 0.48 -
[1] Atici, U., Ersoy, A., 2009. Correlation of Specific Energy of Cutting Saws and Drilling Bits with Rock Brittleness and Destruction Energy. Journal of Materials Processing Technology, 209(5): 2602-2612. https://doi.org/10.1016/j.jmatprotec.2008.06.004 [2] Birdwell, J. E., Washburn, K. E., 2015. Multivariate Analysis Relating Oil Shale Geochemical Properties to NMR Relaxometry. Energy & Fuels, 29(4): 2234-2243. https://doi.org/10.1021/ef502828k [3] Cao, H. R., Zou, Y. R., Lei, Y., et al., 2017. Shale Oil Assessment for the Songliao Basin, Northeastern China, Using Oil Generation⁃Sorption Method. Energy & Fuels, 31(5): 4826-4842. https://doi.org/10.1021/acs.energyfuels.7b00098 [4] Cao, J., Lei, D. W., Li, Y. W., et al., 2015. Ancient High⁃Quality Alkaline Lacustrine Source Rocks Discovered in the Lower Permian Fengcheng Formation, Junggar Basin. Acta Petrolei Sinica, 36(7): 781-790 (in Chinese with English abstract). [5] Dang, W., Zhang, J. C., Nie, H. K., et al., 2022. Microscopic Occurrence Characteristics of Shale Oil and Their Main Controlling Factors: A Case Study of the 3rd Submember Continental Shale of Member 7 of Yanchang Formation in Yan'an Area, Ordos Basin. Acta Petrolei Sinica, 43(4): 507-523 (in Chinese with English abstract). [6] Han, W. Z., Zhao, X. Z., Jin, F. M., et al., 2021. Sweet Spots Evaluation and Exploration of Lacustrine Shale Oil of the Second Member of Paleogene Kongdian Formation in Cangdong Sag, Bohai Bay Basin. Petroleum Exploration and Development, 48(4): 777-786 (in Chinese with English abstract). [7] Howell, J. V., 1960. Glossary of Geology and Related Sciences. American Geological Institute, Washington, D. C., 99-102. [8] Hucka, V., Das, B., 1974. Brittleness Determination of Rocks by Different Methods. International Journal of Rock Mechanics and Mining Sciences & Geomechanics Abstracts, 11(10): 389-392. https://doi.org/10.1016/0148⁃9062(74)91109⁃7 [9] Jarvie, D. M., Hill, R. J., Ruble, T. E., et al., 2007. Unconventional Shale⁃Gas Systems: The Mississippian Barnett Shale of North⁃Central Texas as One Model for Thermogenic Shale⁃Gas Assessment. AAPG Bulletin, 91(4): 475-499. https://doi.org/10.1306/12190606068 [10] Jiang, Q. G., Li, M. W., Qian, M. H., et al., 2016. Quantitative Characterization of Shale Oil in Different Occurrence States and Its Application. Petroleum Geology & Experiment, 38(6): 842-849 (in Chinese with English abstract). [11] Jiang, Z. X., Zhang, W. Z., Liang, C., et al., 2016. Basic Characteristics and Evaluation of Shale Oil Reservoirs. Petroleum Research, 1(2): 149-163. https://doi.org/10.1016/S2096⁃2495(17)30039⁃X [12] Jin, Z. J., Zhu, R. K., Liang, X. P., et al., 2021. Several Issues Worthy of Attention in Current Lacustrine Shale Oil Exploration and Development. Petroleum Exploration and Development, 48(6): 1276-1287 (in Chinese with English abstract). [13] Kausik, R., Fellah, K., Feng, L., et al., 2016. High⁃ and Low⁃Field NMR Relaxometry and Diffusometry of the Bakken Petroleum System. In: SPWLA 57th Annual Logging Symposium. SPWLA, Reykjavik. [14] Korb, J. P., Nicot, B., Jolivet, I., 2018. Dynamics and Wettability of Petroleum Fluids in Shale Oil Probed by 2D T1⁃T2 and Fast Field Cycling NMR Relaxation. Microporous and Mesoporous Materials, 269: 7-11. https://doi.org/10.1016/j.micromeso.2017.05.055 [15] Kuang, L. C., Hou, L. H., Yang, Z., et al., 2021. Key Parameters and Methods of Lacustrine Shale Oil Reservoir Characterization. Acta Petrolei Sinica, 42(1): 1-14 (in Chinese with English abstract). doi: 10.1038/s41401-020-0366-x [16] Li, C. S., Zhang, W. X., Lei, Y., et al., 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, J. B., Jiang, C. Q., Wang, M., et al., 2020. Adsorbed and Free Hydrocarbons in Unconventional Shale Reservoir: A New Insight from NMR T1⁃T2 Maps. Marine and Petroleum Geology, 116: 104311. https://doi.org/10.1016/j.marpetgeo.2020.104311 [18] Li, M. W., Chen, Z. H., Cao, T. T., et al., 2018. Expelled Oils and Their Impacts on Rock⁃Eval Data Interpretation, Eocene Qianjiang Formation in Jianghan Basin, China. International Journal of Coal Geology, 191: 37-48. https://doi.org/10.1016/j.coal.2018.03.001 [19] Li, S. F., Hu, S. Z., Xie, X. N., et al., 2016a. Assessment of Shale Oil Potential Using a New Free Hydrocarbon Index. International Journal of Coal Geology, 156: 74-85. https://doi.org/10.1016/j.coal.2016.02.005 [20] Li, Z., Zou, Y. R., Xu, X. Y., et al., 2016b. Adsorption of Mudstone Source Rock for Shale Oil-Experiments, Model and a Case Study. Organic Geochemistry, 92: 55-62. https://doi.org/10.1016/j.orggeochem.2015.12.009 [21] Liang, W., Li, X. P., 2020. Lithological Exploration and Potential in Mixed Siliciclastic⁃Carbonate Depositional Area of Eastern Pearl River Mouth Basin. Earth Science, 45(10): 3870-3884 (in Chinese with English abstract). [22] Liu, D. G., Zhou, L., Li, S. H., et al., 2020. Characteristics of Source Rocks and Hydrocarbon Generation Models of Fengcheng Formation in Mahu Depression. Acta Sedimentologica Sinica, 38(5): 946-955 (in Chinese with English abstract). [23] Lu, S. F., Huang, W. B., Chen, F. W., et al., 2012. Classification and Evaluation Criteria of Shale Oil and Gas Resources: Discussion and Application. Petroleum Exploration and Development, 39(2): 268-276. https://doi.org/10.1016/S1876⁃3804(12)60042⁃1 [24] Morley, M., 1944. Strength of Materials. Longman Green, London, 70-72. [25] Nie, H. K., Zhang, P. X., Bian, R. K., et al., 2016. Oil Accumulation Characteristics of China Continental Shale. Earth Science Frontiers, 23(2): 55-62 (in Chinese with English abstract). [26] Obert, L., Duvall, W. I., 1967. Rock Mechanics and the Design of Structures in Rock. John Wiley, New York, 78-82. [27] Ramsay, J. G., 1967. Folding and Fracturing of Rockslmi. Mcgraw⁃Hill, London, 44-47. [28] Rickman, R., Mullen, M., Petre, E., et al., 2008. A Practical Use of Shale Petrophysics for Stimulation Design Optimization: All Shale Plays are not Clones of the Barnett Shale. In: SPE Annual Technical Conference & Exhibition. SPE, Denver. [29] Song, Y. Q., Kausik, R., 2019. NMR Application in Unconventional Shale Reservoirs—A New Porous Media Research Frontier. Progress in Nuclear Magnetic Resonance Spectroscopy, 112-113: 17-33. https://doi.org/10.1016/j.pnmrs.2019.03.002 [30] Testamanti, M. N., Rezaee, R., 2019. Considerations for the Acquisition and Inversion of NMR T2 Data in Shales. Journal of Petroleum Science and Engineering, 174: 177-188. https://doi.org/10.1016/j.petrol.2018.10.109 [31] Wang, Z. L., Sun, T., Feng, C. H., et al., 2018. An Improved Method for Predicting Brittleness of Rocks via Well Logs in Tight Oil Reservoirs. Journal of Geophysics and Engineering, 15(3): 1042-1049. https://doi.org/10.1088/1742⁃2140/aaa935 [32] Yagiz, S., 2009. Assessment of Brittleness Using Rock Strength and Density with Punch Penetration Test. Tunnelling and Underground Space Technology, 24(1): 66-74. https://doi.org/10.1016/j.tust.2008.04.002 [33] Yang, Z. F., Tang, Y., Guo, X. G., et al., 2021. Occurrence States and Potential Influencing Factors of Shale Oil in the Permian Fengcheng Formation of Mahu Sag, Junggar Basin. Petroleum Geology & Experiment, 43(5): 784-796 (in Chinese with English abstract). [34] Zhang, J. C., Lin, L. M., Li, Y. X., et al., 2012. Classification and Evaluation of Shale Oil. Earth Science Frontiers, 19(5): 322-331 (in Chinese with English abstract). [35] Zhang, P. F., 2019. Research on Shale Oil Reservoir, Occurrence and Movability Using Nuclear Magnetic Resonance (NMR) (Dissertation). China University of Petroleum, Qingdao (in Chinese with English abstract). [36] Zhang, P. F., Lu, S. F., Li, J. Q., et al., 2020.1D and 2D Nuclear Magnetic Resonance (NMR) Relaxation Behaviors of Protons in Clay, Kerogen and Oil⁃Bearing Shale Rocks. Marine and Petroleum Geology, 114: 104210. https://doi.org/10.1016/j.marpetgeo.2019.104210 [37] Zhi, D. M., Tang, Y., Zheng, M. L., et al., 2019. Geological Characteristics and Accumulation Controlling Factors of Shale Reservoirs in Fengcheng Formation, Mahu Sag, Junggar Basin. China Petroleum Exploration, 24(5): 615-623 (in Chinese with English abstract). doi: 10.3969/j.issn.1672-7703.2019.05.008 [38] Zhou, X. H., Chen, D. X., Xia, Y. X., et al., 2022. Spontaneous Imbibition Characteristics and Influencing Factors of Chang 7 Shale Oil Reservoirs in Longdong Area, Ordos Basin. Earth Science, 47(8): 3045-3055 (in Chinese with English abstract). [39] Zhu, C. F., Guo, W., Li, Y. J., et al., 2021. Effect of Occurrence States of Fluid and Pore Structures on Shale Oil Movability. Fuel, 288: 119847. https://doi.org/10.1016/j.fuel.2020.119847 [40] Zou, C. N., Zhang, G. S., Yang, Z., et al., 2013. Geological Concepts, Characteristics, Resource Potential and Key Techniques of Unconventional Hydrocarbon: On Unconventional Petroleum Geology. Petroleum Exploration and Development, 40(4): 385-399, 454 (in Chinese with English abstract). [41] 曹剑, 雷德文, 李玉文, 等, 2015. 古老碱湖优质烃源岩: 准噶尔盆地下二叠统风城组. 石油学报, 36(7): 781-790. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB201507002.htm [42] 党伟, 张金川, 聂海宽, 等, 2022. 页岩油微观赋存特征及其主控因素——以鄂尔多斯盆地延安地区延长组7段3亚段陆相页岩为例. 石油学报, 43(4): 507-523. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202204005.htm [43] 韩文中, 赵贤正, 金凤鸣, 等, 2021. 渤海湾盆地沧东凹陷孔二段湖相页岩油甜点评价与勘探实践. 石油勘探与开发, 48(4): 777-786. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK202104012.htm [44] 蒋启贵, 黎茂稳, 钱门辉, 等, 2016. 不同赋存状态页岩油定量表征技术与应用研究. 石油实验地质, 38(6): 842-849. https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD201606020.htm [45] 金之钧, 朱如凯, 梁新平, 等, 2021. 当前陆相页岩油勘探开发值得关注的几个问题. 石油勘探与开发, 48(6): 1276-1287. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK202106021.htm [46] 匡立春, 侯连华, 杨智, 等, 2021. 陆相页岩油储层评价关键参数及方法. 石油学报, 42(1): 1-14. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202101001.htm [47] 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 [48] 梁卫, 李小平, 2020. 珠江口盆地东部碎屑岩‒碳酸盐混合沉积区岩性油气藏形成地质条件与潜力. 地球科学, 45(10): 3870-3884. doi: 10.3799/dqkx.2020.174 [49] 刘得光, 周路, 李世宏, 等, 2020. 玛湖凹陷风城组烃源岩特征与生烃模式. 沉积学报, 38(5): 946-955. https://www.cnki.com.cn/Article/CJFDTOTAL-CJXB202005005.htm [50] 聂海宽, 张培先, 边瑞康, 等, 2016. 中国陆相页岩油富集特征. 地学前缘, 23(2): 55-62. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY201602009.htm [51] 杨智峰, 唐勇, 郭旭光, 等, 2021. 准噶尔盆地玛湖凹陷二叠系风城组页岩油赋存特征与影响因素. 石油实验地质, 43(5): 784-796. https://www.cnki.com.cn/Article/CJFDTOTAL-SYSD202105008.htm [52] 张金川, 林腊梅, 李玉喜, 等, 2012. 页岩油分类与评价. 地学前缘, 19(5): 322-331. https://www.cnki.com.cn/Article/CJFDTOTAL-DXQY201205032.htm [53] 张鹏飞, 2019. 基于核磁共振技术的页岩油储集、赋存与可流动性研究(博士学位论文). 青岛: 中国石油大学. [54] 支东明, 唐勇, 郑孟林, 等, 2019. 准噶尔盆地玛湖凹陷风城组页岩油藏地质特征与成藏控制因素. 中国石油勘探, 24(5): 615-623. https://www.cnki.com.cn/Article/CJFDTOTAL-KTSY201905008.htm [55] 周小航, 陈冬霞, 夏宇轩, 等, 2022. 鄂尔多斯盆地陇东地区长7段页岩油储层自发渗吸特征及影响因素. 地球科学, 47(8): 3045-3055. doi: 10.3799/dqkx.2022.208 [56] 邹才能, 张国生, 杨智, 等, 2013. 非常规油气概念、特征、潜力及技术——兼论非常规油气地质学. 石油勘探与开发, 40(4): 385-399, 454. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK201304000.htm