Discussion on genesis and geological significance of "low resistivity and low gas content" of Longmaxi Formation shale in southeastern Sichuan
-
摘要: 为了明确五峰组—龙马溪组页岩“低电阻、低含气”成因，有效指导四川盆地下一步页岩气的勘探部署，依托全区大量钻井调查、解剖及分析化验测试结果，对问题开展了较为详细的研究。该区龙马溪组页岩低电阻率测井按其电性特征、地质特征的差异，可分为小于1 Ω·m和1~10 Ω·m两类。电阻率小于1 Ω·m的页岩气井基本不含气，以干井为主，分布区域相对集中，主要位于川西南、长宁西等地区；其电阻率曲线形态具“细脖子”特征，拉曼反射率普遍在3.70%以上且出现高幅度石墨峰；另外不同状态下岩电实验电阻值变化范围小，且均呈现极低—低电阻特征，说明石墨化造成的岩石骨架导电是影响该类页岩的主要原因。页岩电阻率在1~10 Ω·m范围的钻井分布区域较广，以微含气为主，在盆内、盆外均有分布，其电性、激光拉曼及岩电实验等表现出来的特征与电阻率小于1 Ω·m的页岩差异明显，页岩电阻率曲线具“渐变”特征，激光拉曼实测反射率在3.50% 左右，激光拉曼图谱也没有表现出明显的石墨峰特征。该类页岩进行烘干水及饱和水两种状态下的岩电实验变化范围大，即烘干前、后页岩电阻率变化在7~20倍，且呈现中—高电阻率特征，揭示页岩含水量对页岩电阻率有显著影响。结合实钻资料认为，页岩气保存条件变差、含水率增高是造成该类低阻井的主要原因。Abstract: In order to clarify the genesis of "low resistivity and low gas content" in the shale of Wufeng-Longmaxi formations and effectively guide the next step of shale gas exploration in Sichuan Basin, a detailed study on the problem based on a large number of drilling surveys, dissections, and analysis of laboratory test results in the entire area was carried out herein. Low-resistivity wells of Longmaxi Formation shale in this area can be divided into two types based on their electrical and geological characteristics, which are less than 1 Ω·m and 1-10 Ω·m. Shale gas wells with resistivity less than 1 Ω·m are basically gas-free and mostly dry wells with relatively concentrated distribution areas, mainly located in southwestern Sichuan and western Changning. The resistivity curve of the shale exhibits a "thin neck" characteristic, with a Raman reflectance generally above 3.70% and a high amplitude graphite peak. In addition, the variation range of resistance values in rock electrical experiments under different states is small, and they all exhibit extremely low to low resistance characteristics, indicating that the conductivity of the rock skeleton caused by graphitization is the main factor affecting this type of shale. The drilling distribution area of shale with resistivity in the range of 1-10 Ω·m is relatively wider, mainly with slight gas content, distributed both inside and outside the basin. The characteristics exhibited by its electrical properties, laser Raman, and rock electrical experiments are significantly different from those of shale less than 1 Ω·m. The resistance curve of this type of shale exhibits a "gradual" characteristic, with a measured Raman reflectance of around 3.50% by laser Raman spectroscopy. The laser Raman spectrum also does not show obvious graphite peak characteristics. This type of shale undergoes a wide range of changes in rock electrical experiments under two states: dry water and saturated water, with a change in shale resistivity of 7 to 20 times before and after drying, and exhibits medium to high electrical resistance characteristics, revealing a significant impact of shale water content on shale resistivity. Based on actual drilling data, it is believed that the deterioration of shale gas preservation conditions and the increase in water content are the main reasons for this type of low-resistivity well.
-
Key words:
- low resistivity /
- graohitization /
- high water content /
- preservation condition /
- shale gas /
- Longmaxi Formation /
- southeastern
-
图 1 四川盆地及周缘地区龙马溪组页岩低电阻率井分布
Figure 1. Distribution of shale low-resistivity wells in Longmaxi Formation in Sichuan Basin and surrounding areas
图 2 小于1 Ω·m极低电阻率页岩“细脖子型”特征
Figure 2. "Thin neck" characteristics of shale with extremely low resistivity less than 1 Ω·m
图 3 不同电阻率页岩TOC含量与电阻率值相关关系
Figure 3. Correlation between TOC content and resistivity values of shale with different resistivity
图 4 四川盆地小于1 Ω·m极低电阻率页岩有机质激光拉曼谱图
Figure 4. Laser Raman spectroscopy of organic matter in shale with extremely low resistivity less than 1 Ω·m, Sichuan Basin
图 5 四川盆地小于1 Ω·m极低电阻率页岩不同状态下电阻率统计直方图
Figure 5. Statistical histograms of shale resistivity in different states for shale with extremely low resistivity less than 1 Ω·m, Sichuan Basin
图 6 四川盆地MY1井页岩电阻率随含水饱和度变化趋势
Figure 6. Trend of shale resistivity variation with water saturation in well MY1 in Sichuan Basin
图 7 1~10 Ω·m低电阻率页岩“渐变型”特征
低电阻率页岩段主要集中在龙一亚段—五峰组。
Figure 7. "Gradient type" characteristics of shale with low resistivity of 1-10 Ω·m
图 8 1~10 Ω·m低电阻率页岩与大于10 Ω·m电阻率页岩有机质激光拉曼谱图对比
Figure 8. Comparison of organic matter Laser Raman spectrograms between shales with low resistivity of 1-10 Ω·m and shales with resistivity greater than 10 Ω·m
图 9 四川盆地SHY1井龙马溪组页岩透射电子成像图
Figure 9. Transmission electron imaging of shale in Longmaxi Formation of well SHY1 in Sichuan Basin
图 10 1~10 Ω · m低电阻率页岩与大于10 Ω · m电阻率页岩在不同状态下电阻率变化对比
Figure 10. Comparison of resistivity changes between shale with low resistivity of 1-10 Ω · m and shale with resistivity greater than 10 Ω · m in different states
表 1 四川盆地五峰组—龙马溪组部分典型低电阻率页岩气井测试产能统计
Table 1. Production capacity of some typical low-resistivity shale gas wells in Wufeng-Longmaxi formations in Sichuan Basin
井名 电阻率/(Ω·m) 含气量/(m3/t) 孔隙度/% 测试产量/(104 m3/d) N211井 8.30 直井测试0.7 JYT1井 6.60 3.90 4.30 水平井测试0.96 LY4井 2.80 2.90 水平井测试1.1 H201井 5.10 2.79 产微气、产水 X202井 4.80 水平井测试0.03 SHY1井 4.10 2.28 3.20 未测试 MY1井 0.13 0.10 1.10 未测试 YZ1井 0.60 0.46 1.91 未测试 LY1井 0.59 0.34 0.69 未测试 
下载: 导出CSV
表 2 四川盆地小于1 Ω·m极低电阻率页岩电阻值与激光拉曼反射率对应表
Table 2. Corresponding table of shale resistance values and laser Raman reflectance for shale with extremely low resistivity less than 1 Ω·m, Sichuan Basin
项目 N222井 HY1井 LY1井 MY1井 激光拉曼反射率/% 3.71~3.92 3.80~4.00 3.73 3.76 电阻率/(Ω﹒m) 0.14 0.20 0.60 0.15
下载: 导出CSV
-
[1] 郭旭升, 腾格尔, 魏祥峰, 等. 四川盆地深层海相页岩气赋存机理与勘探潜力[J]. 石油学报, 2022, 43(4): 453-468. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202204001.htmGUO Xusheng, TENGER B, WEI Xiangfeng, et al. Occurrence mechanism and exploration potential of deep marine shale gas in Sichuan Basin[J]. Acta Petrolei Sinica, 2022, 43(4): 453-468. https://www.cnki.com.cn/Article/CJFDTOTAL-SYXB202204001.htm [2] 魏富彬, 刘珠江, 陈斐然, 等. 川东南五峰组—龙马溪组深层、超深层页岩储层特征及其页岩气勘探意义[J]. 石油实验地质, 2023, 45(4): 751-760. doi: 10.11781/sysydz202304751WEI Fubin, LIU Zhujiang, CHEN Feiran, et al. Characteristics of the deep and ultra-deep shale reservoirs of the Wufeng-Longmaxi formations in the southeastern Sichuan Basin and the significance of shale gas exploration[J]. Petroleum Geology & Experiment, 2023, 45(4): 751-760. doi: 10.11781/sysydz202304751 [3] 赵文韬, 荆铁亚, 熊鑫, 等. 海相页岩有机质石墨化特征研究: 以渝东南地区牛蹄塘组为例[J]. 地质科技情报, 2018, 37(2): 183-191. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201802025.htmZHAO Wentao, JING Tieya, XIONG Xin, et al. Graphitization characteristics of organic matters in marine-facies shales[J]. Geological Science and Technology Information, 2018, 37(2): 183-191. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ201802025.htm [4] 王玉满, 魏国齐, 沈均均, 等. 四川盆地及其周缘海相页岩有机质炭化区分布规律与主控因素浅析[J]. 天然气地球科学, 2022, 33(6): 843-859. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX202206001.htmWANG Yuman, WEI Guoqi, SHEN Junjun, et al. Analysis on carbonization distribution and main controlling factors of organic matter in marine shale in Sichuan Basin and its periphery[J]. Natural Gas Geoscience, 2022, 33(6): 843-859. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX202206001.htm [5] 张琴, 赵群, 罗超, 等. 有机质石墨化及其对页岩气储层的影响: 以四川盆地南部海相页岩为例[J]. 天然气工业, 2022, 42(10): 25-36. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202210003.htmZHANG Qin, ZHAO Qun, LUO Chao, et al. Effect of graphitization of organic matter on shale gas reservoirs: take the marine shales in the southern Sichuan Basin as examples[J]. Natural Gas Industry, 2022, 42(10): 25-36. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG202210003.htm [6] 王玉满, 李新景, 王皓, 等. 中上扬子地区下志留统龙马溪组有机质碳化区预测[J]. 天然气地球科学, 2020, 31(2): 151-162. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX202002001.htmWANG Yuman, LI Xinjing, WANG Hao, et al. Prediction of organic matter carbonization zones for Lower Silurian Longmaxi Formation in Middle-Upper Yangtze region[J]. Natural Gas Geoscience, 2020, 31(2): 151-162. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX202002001.htm [7] 黄莉莎, 闫建平, 胡兴中, 等. 川南五峰组—龙马溪组低阻页岩特征分析及启示[J/OL]. 西南石油大学学报(自然科学版), 1-15. [2023-11-05]. http://kns.cnki.net/kcms/detail/51.1718.te.20230927.1013.002.html .HUANG Lisha, YAN Jianping, HU Xingzhong, et al. Characte-ristics analysis and its enlightenment of shale of low resistivity in Wufeng–Longmaxi formation in southern Sichuan Basin[J/OL]. Journal of Southwest Petroleum University (Science & Technology Edition), 1-15. [2023-11-05].http://kns.cnki.net/kcms/detail/51.1718.te.20230927.1013.002.html .[8] 蒋珊, 王玉满, 王书彦, 等. 四川盆地川中古隆起及周缘下寒武统筇竹寺组页岩有机质石墨化区预测[J]. 天然气工业, 2018, 38(10): 19-27. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG201810004.htmJIANG Shan, WANG Yuman, WANG Shuyan, et al. Distribution prediction of graphitized organic matter areas in the Lower Cambrian Qiongzhusi shale in the central Sichuan paleo-uplift and its surrounding areas in the Sichuan Basin[J]. Natural Gas Industry, 2018, 38(10): 19-27. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG201810004.htm [9] 王玉满, 李新景, 陈波, 等. 海相页岩有机质炭化的热成熟度下限及勘探风险[J]. 石油勘探与开发, 2018, 45(3): 385-395. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK201803004.htmWANG Yuman, LI Xinjing, CHEN Bo, et al. Lower limit of thermal maturity for the carbonization of organic matter in marine shale and its exploration risk[J]. Petroleum Exploration and Development, 2018, 45(3): 385-395. https://www.cnki.com.cn/Article/CJFDTOTAL-SKYK201803004.htm [10] 薛子鑫, 姜振学, 郝绵柱, 等. 川南深层页岩有机质石墨化对储层孔隙的控制作用[J]. 中南大学学报(自然科学版), 2022, 53(9): 3532-3544. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202209019.htmXUE Zixin, JIANG Zhenxue, HAO Mianzhu, et al. Controlling effect of organic matter graphitization on reservoir pore structure in deep shale reservoirs, southern Sichuan[J]. Journal of Central South University (Science and Technology), 2022, 53(9): 3532-3544. https://www.cnki.com.cn/Article/CJFDTOTAL-ZNGD202209019.htm [11] 侯宇光, 张坤朋, 何生, 等. 南方下古生界海相页岩极低电阻率成因及其地质意义[J]. 地质科技通报, 2021, 40(1): 80-89. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202101008.htmHOU Yuguang, ZHANG Kunpeng, HE Sheng, et al. Origin and geological significance of ultra-low resistivity in Lower Paleozoic marine shale, South China[J]. Bulletin of Geological Science and Technology, 2021, 40(1): 80-89. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKQ202101008.htm [12] 高和群, 丁安徐, 蔡潇, 等. 中上扬子海相页岩电阻率异常成因分析[J]. 断块油气田, 2016, 23(5): 578-582. https://www.cnki.com.cn/Article/CJFDTOTAL-DKYT201605007.htmGAO Hequn, DING Anxu, CAI Xiao, et al. Genetic analysis of abnor-mal resistivity of Middle-Upper Yangtze marine shales[J]. Fault-Block Oil & Gas Field, 2016, 23(5): 578-582. https://www.cnki.com.cn/Article/CJFDTOTAL-DKYT201605007.htm [13] 邹辰, 吴永辉, 章超, 等. 渝西地区龙马溪组页岩低阻主控因素及有利区预测[J]. 东北石油大学学报, 2023, 47(2): 81-90. https://www.cnki.com.cn/Article/CJFDTOTAL-DQSY202302007.htmZOU Chen, WU Yonghui, ZHANG Chao, et al. Main controlling factors of the low resistivity Longmaxi Formation shale and prediction of favorable area in Yuxi area[J]. Journal of Northeast Petroleum University, 2023, 47(2): 81-90. https://www.cnki.com.cn/Article/CJFDTOTAL-DQSY202302007.htm [14] 邹辰, 李德华, 杨庆, 等. 滇黔北地区龙马溪组有机质石墨化特征及成因[J]. 天然气工业, 2021, 41(S1): 67-72. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG2021S1010.htmZOU Chen, LI Dehua, YANG Qing, et al. Characteristics and genesis of organic matter graphitization in Longmaxi Formation, northern Yunnan and Guizhou[J]. Natural Gas Industry, 2021, 41(S1): 67-72. https://www.cnki.com.cn/Article/CJFDTOTAL-TRQG2021S1010.htm [15] 周天琪. 低温热流体及基底深大断裂对富有机质页岩电性差异的影响[C]//第十七届全国古地理学及沉积学学术会议摘要集——专题21陆相页岩油富集机理与勘探进展. 青岛: [s. n. ], 2023: 9.ZHOU Tianqi. The influence of low temperature thermal fluid and deep fault on the electrical properties of organic rich shale[C]//Summary of the 17th National Academic Conference on Paleogeography and Sedimentology-Topic 21: Mechanism of continental shale oil enrichment and exploration progress. Qingdao: [s. n. ], 2023: 9. [16] 崔瑞康, 孙建孟, 刘行军, 等. 低阻页岩电阻率主控因素研究[J]. 物探与化探, 2022, 46(1): 150-159. https://www.cnki.com.cn/Article/CJFDTOTAL-WTYH202201016.htmCUI Ruikang, SUN Jianmeng, LIU Xingjun, et al. Major controlling factors of low-resistance shale gas reservoirs[J]. Geophysical and Geochemical Exploration, 2022, 46(1): 150-159. https://www.cnki.com.cn/Article/CJFDTOTAL-WTYH202201016.htm [17] 王滢, 何嘉, 寇一龙, 等. 长宁地区龙马溪组页岩储层低电阻率成因[J]. 油气地质与采收率, 2022, 29(3): 53-61. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS202203007.htmWANG Ying, HE Jia, KOU Yilong, et al. Causes of low resistivity of Longmaxi Formation shale reservoirs in Changning area[J]. Petroleum Geology and Recovery Efficiency, 2022, 29(3): 53-61. https://www.cnki.com.cn/Article/CJFDTOTAL-YQCS202203007.htm [18] 王宏坤, 吕修祥, 王玉满, 等. 鄂西下志留统龙马溪组页岩储集特征[J]. 天然气地球科学, 2018, 29(3): 415-423. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201803012.htmWANG Hongkun, LV Xiuxiang, WANG Yuman, et al. The reservoir characteristics of Lower Silurian Longmaxi Formation in western Hubei[J]. Natural Gas Geoscience, 2018, 29(3): 415-423. https://www.cnki.com.cn/Article/CJFDTOTAL-TDKX201803012.htm [19] 刘德汉, 肖贤明, 田辉, 等. 固体有机质拉曼光谱参数计算样品热演化程度的方法与地质应用[J]. 科学通报, 2013, 58(13): 1228-1241. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB201313010.htmLIU Dehan, XIAO Xianming, TIAN Hui, et al. Sample maturation calculated using Raman spectroscopic parameters for solid organics: methodology and geological applications[J]. Chinese Science Bulletin, 2013, 58(11): 1285-1298. https://www.cnki.com.cn/Article/CJFDTOTAL-KXTB201313010.htm [20] 肖贤明, 周秦, 程鹏, 等. 高—过成熟海相页岩中矿物—有机质复合体(MOA)的显微激光拉曼光谱特征作为成熟度指标的意义[J]. 中国科学(地球科学), 2020, 50(9): 1228-1241. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK202009006.htmXIAO Xianming, ZHOU Qin, CHENG Peng, et al. Thermal maturation as revealed by micro-Raman spectroscopy of mineral-organic aggregation (MOA) in marine shales with high and over maturities[J]. Science China (Earth Sciences), 2020, 63(10): 1540-1552. https://www.cnki.com.cn/Article/CJFDTOTAL-JDXK202009006.htm -
计量
- 文章访问数: 506
- HTML全文浏览量: 250
- PDF下载量: 83
- 被引次数: 0
苏公网安备32021102000780号