Analysis and significance of shale reservoir differences between Wujiaping Formation in Hongxing area and Longmaxi Formation in Jiaoshiba area, eastern Sichuan Basin
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摘要: 四川盆地东部红星地区二叠系吴家坪组发育一套黑色富硅富碳页岩储层,目前已成为该地区页岩气领域重要的增储上产阵地。该套页岩储层与焦石坝地区龙马溪组含气页岩段下部①—③小层在沉积环境、页岩品质及含气性等方面具有较好的相似性,主要表现在二者均具备富碳、富硅、高含气的特点,但在后期开发过程中,吴家坪组页岩气层开发效果明显差于焦石坝地区龙马溪组页岩气层。为此,分析了2套页岩储层品质、含气性等方面差异性特征及其主要控制因素。吴家坪组页岩储层矿物组成具有硅质矿物含量低、碳酸盐矿物含量高的特征,有机碳含量高但成烃母质和有机质类型较差;孔隙结构表现为有机质孔隙和层理缝发育程度较低以及孔隙尺度偏小的特征,储层物性及含气性较焦石坝地区龙马溪组页岩储层略差。对比分析认为,沉积背景和沉积作用的差异导致2套页岩储层在岩矿、层理、成烃母质类型等原生品质上存在差异,这是2套储层在物性和含气性方面存在差异的物质基础;后续的构造保存条件等宏观地质条件的差异,导致2套储层在孔隙类型、孔隙尺度、孔隙度及含气性等方面存在较明显的差异。此外,探讨了2套储层差异性特征对其开发效果的影响,并针对2套页岩储层的差异性提出了相应的开发工程工艺技术对策。Abstract: In the Hongxing area of the eastern Sichuan Basin, the Permian Wujiaping Formation developed a set of black, silicon-rich, and carbon-rich shale reservoirs, which are currently pivotal for enhancing shale gas reserves and production in the region. These shale reservoirs show strong similarities with the lower sections (layers ① to ③) of the gas-bearing shale in the Longmaxi Formation of the Jiaoshiba area in terms of sedimentary environment, shale quality, and gas content. Both formations are characterized by high carbon, silicon, and gas contents. However, in later stages of development, the shale gas reservoirs of the Wujiaping Formation were significantly less productive compared to those in the Longmaxi Formation in the Jiaoshiba area. To address this, the study analyzes the differences in reservoir quality and gas content between the two shale sets and their primary controlling factors. The results reveal that the shale reservoir in the Wujiaping Formation is characterized by a low silica mineral content and a high carbonate mineral content. Although it has a high organic carbon content, the kerogen types and organic matter are relatively poorer. The pore structure is marked by less developed organic matter pores and lamellar fractures, with smaller pore sizes. Overall, its reservoir physical properties and gas content are slightly inferior to those of the Longmaxi Formation shale in the Jiaoshiba area. Comparative analysis suggests that differences in sedimentary backgrounds and processes lead to primary quality differences in mineral and lithological composition, lamellation, and kerogen types between the two shale reservoirs. These differences form the material basis for variations in physical properties and gas content. Furthermore, differences in subsequent structural preservation conditions and other macro-geological factors lead to significant disparities between the two reservoirs in terms of pore types, sizes, porosity, and gas content. In addition, the study explores the impact of these distinctive characte-ristics on the development effectiveness of the two reservoirs and proposes corresponding engineering and technological strategies tailored to the differences in the development of these reservoirs.
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图 4 川东红星地区吴家坪组页岩储层与焦石坝地区龙马溪组页岩储层微观对比照片
a.硅质骨针类化石,吴家坪组,HY1井,3 309 m;b.硅质类放射虫,吴家坪组,HY1井,3 305 m;c.硅质类放射虫,龙马溪组,JYC井,2 558 m;d.硅质类放射虫,龙马溪组,JYB井,2 407 m;e.钙质介屑顺层展布,吴家坪组,HY1井,3 306 m;f.钙质介屑顺层展布,吴家坪组,HY1井,3 301m;g.碳酸盐矿物晶粒展布于地层中,龙马溪组,JYC井,2 571 m;h.阴极发光碳酸盐矿物晶粒,龙马溪组,JYB井,2 114 m。
Figure 4. Microscopic photos comparing shale reservoirs in Wujiaping Formation of Hongxing area and Longmaxi Formation of Jiaoshiba area, eastern Sichuan Basin
图 5 川东红星地区吴家坪组页岩与焦石坝地区龙马溪组页岩储层纹/夹层岩心、薄片对比照片
图中黄色箭头指示纹/夹层岩心特征。HY1井吴家坪组:a.3 309 m,c.3 299 m,e.3 302 m,g-h.3 296 m;JYA井龙马溪组:b.2 323 m,d.2 335 m,f.2 285 m。
Figure 5. Photos of core and thin section comparing laminae and interbedded layers between shale reservoirs of Wujiaping Formation of Hongxing area and Longmaxi Formation of Jiaoshiba area, eastern Sichuan Basin
图 6 川东红星地区吴家坪组页岩储层(a-c)与焦石坝地区龙马溪组页岩储层(d-f)成烃生物微观对比照片
a.藻纹层,HY1井,3 308 m;b.藻纹层及分散状藻残屑,HY1井,3 309 m;c.高等植物碎片,HY1井,3 305 m;d.硅质放射虫,JYA井2 361 m;e.硅质放射虫,JYA井,2 359 m;f.波罗的海藻,JYA井,2 353 m。
Figure 6. Microscopic photos of hydrocarbon-generating organisms between shale reservoirs of Wujiaping Formation of Hongxing area (a-c) and Longmaxi Formation of Jiaoshiba area (d-f), eastern Sichuan Basin
图 7 川东红星地区吴家坪组页岩储层(a-d)与焦石坝龙马溪组页岩储层(e-h)孔隙类型对比照片
a.不规则状有机质孔隙,有机质表面面孔率9.15%,HY1井,3 309 m;b.植物碎片内少量气泡孔,面孔率低,HY1井,3 304 m;c.长石内溶蚀孔隙,面孔率低,HY1井,3 302 m;d.方解石内溶蚀孔隙,面孔率低,连通性较差,HY1井,3 299 m;e.圆形—椭圆形有机质孔隙,有机质表面面孔率32%,JYA井,2 361 m;f.圆形有机质孔隙,孔隙孔径大,JYB井,2 399 m;g.黏土孔隙,黏土成岩收缩孔缝,JYB井,2 389 m;h.碎屑孔隙,少量方解石溶蚀孔,JYA井,2 353 m。
Figure 7. Microscopic photos comparing pore types between shale reservoirs in Wujiaping Formation of Hongxing area (a-d) and Longmaxi Formation of Jiaoshiba area (e-h), eastern Sichuan Basin
图 8 川东红星地区吴家坪组页岩储层(a)与焦石坝地区龙马溪组页岩储层(b)层理缝对比岩心照片
a.吴家坪组岩心抛光面层理缝照片,较稀疏,55条/m,HY1井,3 304~3 304.3 m;b.龙马溪组岩心抛光面层理缝照片,密集发育,420条/m,JYA井,2 344~2 344.3 m。
Figure 8. Core photos comparing laminae and fractures between shale reservoirs in Wujiaping Formation of Hongxing area (a) and Longmaxi Formation of Jiaoshiba area (b), eastern Sichuan Basin
表 1 川东红星地区吴家坪组页岩储层与焦石坝地区龙马溪组页岩储层原生品质参数对比
Table 1. Comparison of primary quality parameters between shale reservoirs in Wujiaping Formation of Hongxing area and Longmaxi Formation of Jiaoshiba area, eastern Sichuan Basin
页岩储层 岩矿特征 纹/夹层特征 地球化学特征 硅质 碳酸盐矿物 隐性纹层 显性薄夹层 成烃母质 有机碳含量/% Ro/% 龙马溪组①-③小层,厚20 m 含量65%~70%,生物硅为主 含量10%左右,分散晶粒状 陆源长英质纹层 凝灰岩薄夹层,硅质条带(见) 硅质类浮游生物、藻类、少量陆生孢型植物 3.5~6.0 2.58 吴家坪组,厚18 m 含量43%~57%,生物硅/硅化 含量22%~45%,钙质生屑/交代成因 硅质纹层、钙质介屑纹层 凝灰岩薄夹层、钙质介屑夹层,硅质条带(发育) 硅质类浮游生物、藻类、部分陆生高等植物 5.0~9.5 2.25 表 2 川东红星地区吴家坪组页岩储层与焦石坝地区龙马溪组页岩储层物性及含气性参数对比
Table 2. Comparison of physical properties and gas content parameters between shale reservoirs in Wujiaping Formation of Hongxing area and Longmaxi Formation of Jiaoshiba area, eastern Sichuan Basin
层位 孔隙类型 有机质孔隙 孔隙尺度占比 孔隙连通性 页理缝/(条/m) 孔隙度/% 含气量/(m3/t) 游离气∶吸附气 面孔率/% 孔径 体积占比/% 龙马溪组①-③小层 有机质孔隙为主,其次为黏土孔隙,少量碎屑孔隙 30.0 数十nm~2.5 μm,最大达2.5 μm左右 60 微孔24%,中孔71%,大孔5% 大孔小喉型(墨水瓶型孔隙) 420 5.0~6.5 6.0~7.0 6∶4 吴家坪组 有机质、碎屑孔隙为主,少量黏土孔隙 9.2 数十~数百nm,最大619 nm 40 微孔47%,中孔41%,大孔12% 大孔小喉型(墨水瓶型孔隙) 45 4.6~6.2 4.0~6.6 4∶6 -
[1] 胡德高, 周林, 包汉勇, 等. 川东红星地区HY1井二叠系页岩气勘探突破及意义[J]. 石油学报, 2023, 44(2): 241-252.HU Degao, ZHOU Lin, BAO Hanyong, et al. Breakthrough and significance of Permian shale gas exploration of well HY1 in Hongxing area, eastern Sichuan Basin[J]. Acta Petrolei Sinica, 2023, 44(2): 241-252. [2] 郑爱维, 孟志勇, 李凯, 等. 川东红星地区二叠系吴家坪组页岩储层纵向非均质性特征及其发育主控因素[J]. 天然气地球科学, 2023, 34(9): 1500-1514.ZHENG Aiwei, MENG Zhiyong, LI Kai, et al. Vertical heterogeneity characteristics and main controlling factors of the Permian Wujiaping Formation shale reservoir in Hongxing area, eastern Sichuan[J]. Natural Gas Geoscience, 2023, 34(9): 1500-1514. [3] 周志, 翟刚毅, 石砥石, 等. 鄂西—渝东北地区五峰组—龙马溪组页岩气成藏地质条件分析[J]. 石油实验地质, 2019, 41(1): 1-9. doi: 10.11781/sysydz201901001ZHOU Zhi, ZHAI Gangyi, SHI Dishi, et al. Shale gas reservoir geology of the Upper Ordovician Wufeng Formation-Lower Silurian Longmaxi Formation in western Hubei and northeastern Chongqing[J]. Petroleum Geology & Experiment, 2019, 41(1): 1-9. doi: 10.11781/sysydz201901001 [4] 孟志勇. 四川盆地涪陵地区五峰组—龙马溪组含气页岩段纵向非均质性及其发育主控因素[J]. 石油与天然气地质, 2016, 37(6): 838-846.MENG Zhiyong. Vertical heterogeneity and its controlling factors of the gas shale in the Wufeng-Longmaxi Fms in Fuling area, the Sichuan Basin[J]. Oil & Gas Geology, 2016, 37(6): 838-846. [5] 李凤杰, 刘殿鹤, 刘琪. 四川宣汉地区吴家坪组硅质岩地球化学特征及其成因探讨[J]. 天然气地球科学, 2010, 21(1)62-67.LI Fengjie, LIU Dianhe, LIU Qi. Geochemical characteristics and genesis discussion of Wujiaping Formation siliceous rocks in Xuanhan area of Sichuan Basin[J]. Natural Gas Geoscience, 2010, 21(1): 62-67. [6] 林良彪, 陈洪德, 朱利东. 重庆石柱吴家坪组硅质岩地球化学特征[J]. 矿物岩石, 2010, 30(3): 52-58.LIN Liangbiao, CHEN Hongde, ZHU Lidong. Geochemical characteristics of silicalites from Wujiaping Formation in Shizhu, Chongqing[J]. Journal of Mineralogy and Petrology, 2010, 30(3): 52-58. [7] 石文睿, 张占松, 黄梓桑, 等. 低阻页岩气储层含气饱和度计算方法: 以涪陵地区焦石坝区块为例[J]. 断块油气田, 2022, 29(2): 183-188.SHI Wenrui, ZHANG Zhansong, HUANG Zisang, et al. Study on calculation method of gas saturation in low-resistivity shale gas reservoir: a case study of Jiaoshiba block in Fuling area[J]. Fault-Block Oil and Gas Field, 2022, 29(2): 183-188. [8] 张士万, 孟志勇, 郭战峰, 等. 涪陵地区龙马溪组页岩储层特征及其发育主控因素[J]. 天然气工业, 2014, 34(12): 16-24.ZHANG Shiwan, MENG Zhiyong, GUO Zhanfeng, et al. Characteristics and major controlling factors of shale reservoirs in the Longmaxi Fm, Fuling area, Sichuan Basin[J]. Natural Gas Industry, 2014, 34(12): 16-24. [9] 赵志根, 唐修义. 低温氮吸附法测试煤中微孔隙及其意义[J]. 煤田地质与勘探, 2001, 29(5): 28-30.ZHAO Zhigen, TANG Xiuyi. Study of micropore in coal by low-temperature nitrogen adsorption method and its significance[J]. Coal Geology & Exploration, 2001, 29(5): 28-30. [10] 严继民, 张培元. 吸附与凝聚: 固体的表面与孔[M]. 北京: 科学出版社, 1979.YAN Jimin, ZHANG Peiyuan. Adsoption & condensation[M]. Beijing: Science Press, 1979. [11] DE BORE J H. The shape of capillaries[M]//EVERETT D H, STONE F S. The structure and properties of porous materials. London: Butterworth, 1958. [12] 陈尚斌, 朱炎铭, 王红岩, 等. 川南龙马溪组页岩气储层纳米孔隙结构特征及其成藏意义[J]. 煤炭学报, 2012, 37(3): 438-444.CHEN Shangbin, ZHU Yanming, WANG Hongyan, et al. Structure characteristics and accumulation significance of nanopores in Longmaxi shale gas reservoir in the southern Sichuan Basin[J]. Journal of China Coal Society, 2012, 37(3): 138-444. [13] 何治亮, 聂海宽, 胡东风, 等. 深层页岩气有效开发中的地质问题: 以四川盆地及其周缘五峰组—龙马溪组为例[J]. 石油学报, 2020, 41(4): 379-391.HE Zhiliang, NIE Haikuan, HU Dongfeng, et al. Geological problems in the effective development of deep shale gas: a case study of Upper Ordovician Wufeng-Lower Silurian Longmaxi formations in Sichuan Basin and its periphery[J]. Acta Petrolei Sinica, 2020, 41(4): 379-391. [14] 郭伟, 李熙喆, 张晓伟, 等. 深水陆棚富有机质页岩沉积微相—微地貌及其对储层的控制作用: 以四川盆地南部五峰组—龙马溪组页岩为例[J]. 石油学报, 2022, 43(8): 1089-1106.GUO Wei, LI Xizhe, ZHANG Xiaowei, et al. Sedimentary microfacies and microrelief of organic-rich shale in deep-water shelf and their control on reservoirs: a case study of shale from Wufeng-Longmaxi formations in southern Sichuan Basin[J]. Acta Petrolei Sinica, 2022, 43(8): 1089-1106. [15] 胡宗全, 杜伟, 朱彤, 等. 四川盆地及其周缘五峰组—龙马溪组细粒沉积的层序地层与岩相特征[J]. 石油与天然气地质, 2022, 43(5): 1024-1038.HU Zongquan, DU Wei, ZHU Tong, et al. Sequence stratigraphy and lithofacies characteristics of fine-grained deposits of Wufeng- Longmaxi formations in the Sichuan Basin and on its periphery[J]. Oil & Gas Geology, 2022, 43(5): 1024-1038. [16] 梁峰, 吴伟, 张琴, 等. 四川盆地南部下寒武统筇竹寺组页岩孔隙结构特征与页岩气赋存模式[J]. 天然气工业, 2024, 44(3): 131-142.LIANG Feng, WU Wei, ZHANG Qin, et al. Shale pore structure characteristics and shale gas occurrence pattern of the Lower Cambrian Qiongzhusi Formation in the southern Sichuan Basin[J]. Natural Gas Industry, 2024, 44(3): 131-142. [17] 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 [18] 魏富彬, 刘珠江, 陈斐然, 等. 川东南地区龙马溪组页岩"低电阻、低含气"成因及地质意义[J]. 石油实验地质, 2023, 45(6): 1089-1096. doi: 10.11781/sysydz2023061089WEI Fubin, LIU Zhujiang, CHEN Feiran, et al. Discussion on genesis and geological significance of "low resistivity and low gas content" of Longmaxi Formation shale in southeastern Sichuan[J]. Petroleum Geology & Experiment, 2023, 45(6): 1089-1096. doi: 10.11781/sysydz2023061089