Characteristics of reservoir space and sweet spot evaluation of shale oil in the second member of Paleogene Funing Formation in Subei Basin: a case study of well QY1 in Qintong Sag
-
摘要: 苏北盆地古近系阜宁组二段是常规油重点产层,同时也是中国东部陆相页岩油勘探开发的优选层位。对溱潼凹陷QY1井岩心样品进行分析测试表明,该套页岩具有低有机质丰度、较低镜质体反射率(Ro)、矿物组分均衡及孔隙网络复杂的特点;运用岩石学及地球化学方法等对该页岩油储层的岩相特征、储集空间特征、含油性与可动性、脆性指数与可压性特征等进行研究,指明了生产甜点段。阜二段是一套混积页岩纹层型储层,矿物组成以黏土、长英质和碳酸盐矿物为主,有机碳含量平均值为1.32%,Ro为0.9%~1.1%;平均孔隙度中下部为4%,上部为2.2%。根据“有机质丰度+构造特征+岩性”将阜二段页岩划分为6种岩相,其储集性具有明显差异,纹层发育特征的差异是导致不同岩相具有不同储集空间特征的重要原因。除低有机质纹层/层状灰云质页岩外,其他岩相都具有较好的含油性;高有机质层状灰质页岩的有机碳含量最高。纹层数量与油气可动性具有较好的对应性,从中有机质纹层状含灰云页岩到高有机质块状泥岩,平均含油饱和度指数从202.62 mg/g降至77.83 mg/g。高有机质块状泥岩由于存在大量塑性矿物,造缝效果是6种岩相中最差的。中有机质纹层状含灰云页岩是最优岩相,中有机质层状含灰云页岩和中有机质纹层/层状灰云质页岩略差,但也可以作为优势岩相成为勘探开发的重点。根据优势岩相在纵向上的分布,优选阜二段Ⅰ亚段③—⑤小层和Ⅱ亚段②—④小层为该区地质甜点段。Abstract: The second member of the Paleogene Funing Formation in the Subei Basin is a key production layer for conventional oil and an optimal target for the exploration and development of continental shale oil in East China. The analysis and testing of core samples from well QY1 in the Qintong Sag indicate that the shale features low total organic carbon (TOC) content, relatively low vitrinite reflectance (Ro), balanced mineral composition, and a complex pore network. Using petrological and geochemical methods, the lithofacies characteristics, reservoir space characteristics, oil-bearing and mobility characteristics, brittleness index, and compressibility characteristics of this shale oil reservoir were studied to identify production sweet spots. The second member of the Funing Formation is a mixed shale layered reservoir, with mineral composition mainly consisting of clay minerals, felsic minerals, and carbonate minerals. The average TOC value is 1.32%, and Ro ranges from 0.9% to 1.1%. The average porosity is 4% in the middle and lower parts and 2.2% in the upper part. Based on the abundance of organic matter, structural characteristics, and lithology, the shale of the second member of the Funing Formation can be divided into six lithofacies, with significant differences in reservoir properties. The development characteristics of the laminae are an important reason for the different reservoir space characteristics among different lithofacies. Except for low organic matter laminated/layered shale with poor calcite and dolomite, other lithofacies have good oil content. The high organic matter layered shale with rich calcite demonstrates the highest TOC content. The number of layers correlates well with oil and gas mobility, with the average OSI value decreasing from 202.62 mg/g in medium organic matter laminae shale with poor calcite and dolomite to 77.83 mg/g in high organic matter massive mudstone. High organic matter massive mudstone, due to the presence of a large amount of plastic minerals, has the worst fracturing effect among the six types of lithofacies. Medium organic matter laminae shale with poor calcite and dolomite is the optimal lithofacies, while medium organic matter layered shale with poor calcite and dolomite and medium organic matter layered shale with rich calcite and dolomite are slightly less favorable but can still be key targets for exploration and development. Based on the vertical distribution of the dominant lithofacies, sublayers ③ to ⑤ of submember Ⅰ and sublayers ② to ④ of submember Ⅱ of the second member of the Funing Formation are selected as geological sweet spots in this area.
-
Key words:
- reservoir space /
- sweet spot evaluation /
- shale oil /
- Funing Formation /
- Paleogene /
- Qingtong Sag /
- Subei Basin
-
表 1 苏北盆地溱潼凹陷阜宁组二段岩相基本特征
Table 1. Characteristics of lithofacies of second member of Funing Formation, Qintong Sag, Subei Basin
岩相类型 岩心照片 薄片照片 矿物组分图 三元图 ω(TOC)/% ①中有机质纹层状含灰云页岩 $ \frac{0.59 \sim 3.27}{1.32(78)}$ ②中有机质层状含灰云质页岩 $ \begin{array}{r} 0.32 \sim 2.69 \\ \hline 1.35(59) \end{array}$ ③中有机质纹层/层状灰云质页岩 $ \frac{0.36 \sim 4.92}{1.20(88)}$ ④低有机质纹层/层状灰云质页岩 $ \begin{gathered} 0.12 \sim 1.66 \\ \hline 0.52(99) \end{gathered}$ ⑤高有机质层状灰质页岩 $ \frac{1.60 \sim 3.49}{2.42(32)}$ ⑥高有机质块状泥岩 $ \begin{array}{r} 1.64 \sim 2.27 \\ \hline 2.04(20) \end{array}$ 注: ω(TOC)数据意义为$ \frac{\text { 最小值 最大值 }}{\text { 平均值(样品数) }}$。 表 2 苏北盆地溱潼凹陷阜宁组二段各岩相储集空间特征
Table 2. Reservoir space characteristics of various lithofacies in second member of Funing Formation, Qintong Sag, Subei Basin
岩相类型 扫描电镜图像 孔隙形态 孔径分布 孔隙度/% ①中有机质纹层状含灰云页岩 $ \begin{gathered} 0.65 \sim 7.18 \\ \hline 4.14(86) \end{gathered}$ ②中有机质层状含灰云页岩 $ \begin{gathered} 0.17 \sim 8.49 \\ \hline 4.33(63) \end{gathered}$ ③中有机质纹层/层状灰云质页岩 $ \frac{0.24 \sim 9.05}{4.09(98)}$ ④低有机质纹层/层状灰云质页岩 $ \frac{0.27 \sim 7.13}{4.49(111)}$ ⑤高有机质层状灰质页岩 $ \frac{1.43 \sim 9.01}{2.50(35)}$ ⑥高有机质块状泥岩 $ \frac{2.48 \sim 7.86}{5.03(20)}$ 注: 孔隙度数据意义为$ \frac{\text { 最小值 } \sim \text { 最大值 }}{\text { 平均值(样品数) }}$。 表 3 苏北盆地溱潼凹陷阜宁组二段各岩相可压性特征
Table 3. Compressibility characteristics of each lithofacies in second member of Funing Formation, well QY1, Qintong Sag, Subei Basin
项目 ①中有机质纹层状含灰云页岩 ②中有机质层状含灰云页岩 ③中有机质纹层/层状灰云质页岩 ④低有机质纹层/层状灰云质页岩 ⑤高有机质层状灰质页岩 ⑥高有机质块状泥岩 三轴力学压前照片 三轴力学压后照片 薄片照片 脆性塑性矿物占比 表 4 页岩层系富集层评价标准[25]
Table 4. Evaluation criteria for "sweet spot" of shale strata
核心要素 评价参数 北美 中国 含油性 TOC含量大于2%,氢指数大于400 mg/g,Ro>1.0% TOC含量大于1%,S1>2 mg/g,Ro>1.0% 储集性 厚度大于25~30 m(理想值大于50 m),平均孔隙度大于6%~12%,发育天然裂缝 厚度大于10 m,孔隙度大于3%,裂缝发育 可动性 页岩段具气测显示和测试产量,地层超压等 地层压力系数大于1.0,地层超压 可压性 硅/钙质等脆性矿物含量大于45%,蒙脱石等黏土矿物含量低 脆性指数大于30%,黏土矿物含量小于35% 可采性 埋深小于4 100 m 埋深小于4 500 m -
[1] 郭旭升, 蔡勋育, 刘金连, 等. 中国石化"十三五"天然气勘探进展与前景展望[J]. 天然气工业, 2021, 41(8): 12-22.GUO Xusheng, CAI Xunyu, LIU Jinlian, et al. Natural gas exploration progress of SINOPEC during the 13th Five-Year Plan and prospect forecast during the 14th Five-Year Plan[J]. Natural Gas Industry, 2021, 41(8): 12-22. [2] 邹才能, 潘松圻, 荆振华, 等. 页岩油气革命及影响[J]. 石油学报, 2020, 41(1): 1-12.ZOU Caineng, PAN Songqi, JING Zhenhua, et al. Shale oil and gas revolution and its impact[J]. Acta Petrolei Sinica, 2020, 41(1): 1-12. [3] 马永生, 黎茂稳, 蔡勋育, 等. 中国海相深层油气富集机理与勘探开发: 研究现状、关键技术瓶颈与基础科学问题[J]. 石油与天然气地质, 2020, 41(4): 655-672.MA Yongsheng, LI Maowen, CAI Xunyu, et al. Mechanisms and exploitation of deep marine petroleum accumulations in China: advances, technological bottlenecks and basic scientific problems[J]. Oil & Gas Geology, 2020, 41(4): 655-672. [4] 王作乾, 范喆, 陈希, 等. 2022年度全球油气开发现状、形势及启示[J]. 石油勘探与开发, 2023, 50(5): 1016-1031.WANG Zuoqian, FAN Zhe, CHEN Xi, et al. Global oil and gas development in 2022: situation, trend and enlightenment[J]. Petroleum Exploration and Development, 2023, 50(5): 1016-1031. [5] 郭旭升, 魏志红, 魏祥峰, 等. 四川盆地侏罗系陆相页岩油气富集条件及勘探方向[J]. 石油学报, 2023, 44(1): 14-27.GUO Xusheng, WEI Zhihong, WEI Xiangfeng, et al. Enrichment conditions and exploration direction of Jurassic continental shale oil and gas in Sichuan Basin[J]. Acta Petrolei Sinica, 2023, 44(1): 14-27. [6] 金之钧, 王冠平, 刘光祥, 等. 中国陆相页岩油研究进展与关键科学问题[J]. 石油学报, 2021, 42(7): 821-835.JIN Zhijun, WANG Guanping, LIU Guangxiang, et al. Research progress and key scientific issues of continental shale oil in China[J]. Acta Petrolei Sinica, 2021, 42(7): 821-835. [7] 何发岐, 徐兵威, 邵隆坎. 再论油气勘探开发哲学和创新性思维: 纪念"中国陆上第一口油井"延1井[J]. 油气藏评价与开发, 2022, 12(2): 265-273.HE Faqi, XU Bingwei, SHAO Longkan. On philosophy and innovative thinking of oil & gas exploration and development: commemoration of the first oil well on land in China, well-Yan1[J]. Reservoir Evaluation and Development, 2022, 12(2): 265-273. [8] 卢双舫, 黄文彪, 陈方文, 等. 页岩油气资源分级评价标准探讨[J]. 石油勘探与开发, 2012, 39(2): 249-256.LU Shuangfang, HUANG Wenbiao, CHEN Fangwen, et al. Classification and evaluation criteria of shale oil and gas resources: discussion and application[J]. Petroleum Exploration and Development, 2012, 39(2): 249-256. [9] 杨智, 邹才能, 付金华, 等. 大面积连续分布是页岩层系油气的标志特征: 以鄂尔多斯盆地为例[J]. 地球科学与环境学报, 2019, 41(4): 459-474.YANG Zhi, ZOU Caineng, FU Jinhua, et al. Characteristics and "sweet area (section)" evaluation of continuous tight & shale oil and gas in Ordos Basin, north-central China[J]. Journal of Earth Sciences and Environment, 2019, 41(4): 459-474. [10] 赵文智, 朱如凯, 胡素云, 等. 陆相富有机质页岩与泥岩的成藏差异及其在页岩油评价中的意义[J]. 石油勘探与开发, 2020, 47(6): 1079-1089.ZHAO Wenzhi, ZHU Rukai, HU Suyun, et al. Accumulation contribution differences between lacustrine organic-rich shales and mudstones and their significance in shale oil evaluation[J]. Petroleum Exploration and Development, 2020, 47(6): 1079-1089. [11] 邹才能, 赵群, 丛连铸, 等. 中国页岩气开发进展、潜力及前景[J]. 天然气工业, 2021, 41(1): 1-14.ZOU Caineng, ZHAO Qun, CONG Lianzhu, et al. Development progress, potential and prospect of shale gas in China[J]. Natural Gas Industry, 2021, 41(1): 1-14. [12] 郭秋麟, 米石云, 张倩, 等. 中国页岩油资源评价方法与资源潜力探讨[J]. 石油实验地质, 2023, 45(3): 402-412. doi: 10.11781/sysydz202303402GUO Qiulin, MI Shiyun, ZHANG Qian, et al. Assessment methods and potential of shale oil resources in China[J]. Petroleum Geology & Experiment, 2023, 45(3): 402-412. doi: 10.11781/sysydz202303402 [13] 吴松涛, 朱如凯, 罗忠, 等. 中国中西部盆地典型陆相页岩纹层结构与储层品质评价[J]. 中国石油勘探, 2022, 27(5): 62-72.WU Songtao, ZHU Rukai, LUO Zhong, et al. Laminar structure of typical continental shales and reservoir quality evaluation in central-western basins in China[J]. China Petroleum Exploration, 2022, 27(5): 62-72. [14] 王然, 何文军, 赵辛楣, 等. 准噶尔盆地吉174井芦草沟组页岩油地质剖面分析[J]. 油气藏评价与开发, 2022, 12(1): 192-203.WANG Ran, HE Wenjun, ZHAO Xinmei, et al. Geological section analysis of shale oil in Lucaogou Formation of well-Ji-174, Junggar Basin[J]. Reservoir Evaluation and Development, 2022, 12(1): 192-203. [15] YU Shaoyong, 刘玉慧. 页岩及致密地层油气井的生产特征及可采储量计算方法[J]. 油气藏评价与开发, 2021, 11(2): 146-153.YU Shaoyong, LIU Yuhui. Production performance and EUR forecast of wells producing from tight/shale reservoirs[J]. Reservoir Evaluation and Development, 2021, 11(2): 146-153. [16] 李志明, 孙中良, 鲍云杰, 等. 冀北坳陷中元古界洪水庄组页岩油勘探前景探讨[J]. 石油实验地质, 2023, 45(1): 29-40. doi: 10.11781/sysydz202301029LI Zhiming, SUN Zhongliang, BAO Yunjie, et al. Discussion on prospecting shale oil potential of Mesoproterozoic Hongshuizhuang Formation in the Jibei Depression[J]. Petroleum Geology & Experiment, 2023, 45(1): 29-40. doi: 10.11781/sysydz202301029 [17] 冯动军. 四川盆地侏罗系大安寨段陆相页岩油气地质特征及勘探方向[J]. 石油实验地质, 2022, 44(2): 219-230. doi: 10.11781/sysydz202202219FENG Dongjun. Geological characteristics and exploration direction of continental shale gas in Jurassic Daanzhai Member, Sichuan Basin[J]. Petroleum Geology & Experiment, 2022, 44(2): 219-230. doi: 10.11781/sysydz202202219 [18] 云露, 何希鹏, 花彩霞, 等. 苏北盆地溱潼凹陷古近系陆相页岩油成藏地质特征及资源潜力[J]. 石油学报, 2023, 44(1): 176-187.YUN Lu, HE Xipeng, HUA Caixia, et al. Accumulation characteristics and resource potential of Paleogene continental shale oil in Qintong Sag of Subei Basin[J]. Acta Petrolei Sinica, 2023, 44(1): 176-187. [19] 昝灵, 白鸾羲, 印燕铃, 等. 苏北盆地溱潼凹陷古近系阜宁组二段页岩油基本特征及成因分析[J]. 石油实验地质, 2023, 45(2): 356-365. doi: 10.11781/sysydz202302356ZAN Ling, BAI Luanxi, YIN Yanling, et al. Basic characteristics and genesis analysis of shale oil in the second member of Paleogene Funing Formation in Qintong Sag, Subei Basin[J]. Petroleum Geology & Experiment, 2023, 45(2): 356-365. doi: 10.11781/sysydz202302356 [20] 侯连华, 吴松涛, 姜晓华, 等. 页岩油地质评价实验方法现状、挑战与发展方向[J]. 石油学报, 2023, 44(1): 72-90.HOU Lianhua, WU Songtao, JIANG Xiaohua, et al. Situation, challenge and future direction of experimental methods for geological evaluation of shale oil[J]. Acta Petrolei Sinica, 2023, 44(1): 72-90. [21] 赵兰. 致密砂岩储层微裂缝发育特征及对物性的影响: 以杭锦旗地区十里加汗区带为例[J]. 油气藏评价与开发, 2022, 12(2): 285-291.ZHAO Lan. Development characteristics of microfractures in tight sandstone reservoir and its influence on physical properties: a case study of Shiligiahan zone in Hangjinqi[J]. Petroleum Reservoir Evaluation and Development, 2022, 12(2): 285-291. [22] 赵金洲, 许文俊, 李勇明, 等. 页岩气储层可压性评价新方法[J]. 天然气地球科学, 2015, 26(6): 1165-1172.ZHAO Jinzhou, XU Wenjun, LI Yongming, et al. A new method for fracability evaluation of shale-gas reservoirs[J]. Natural Gas Geoscience, 2015, 26(6): 1165-1172. [23] 李宁, 冯周, 武宏亮, 等. 中国陆相页岩油测井评价技术方法新进展[J]. 石油学报, 2023, 44(1): 28-44.LI Ning, FENG Zhou, WU Hongliang, et al. New advances in methods and technologies for well logging evaluation of continental shale oil in China[J]. Acta Petrolei Sinica, 2023, 44(1): 28-44. [24] 唐颖, 邢云, 李乐忠, 等. 页岩储层可压裂性影响因素及评价方法[J]. 地学前缘, 2012, 19(5): 356-363.TANG Ying, XING Yun, LI Lezhong, et al. Influence factors and evaluation methods of the gas shale fracability[J]. Earth Science Frontiers, 2012, 19(5): 356-363. [25] 孙龙德, 赵文智, 刘合, 等. 页岩油"甜点"概念及其应用讨论[J]. 石油学报, 2023, 44(1): 1-13.SUN Longde, ZHAO Wenzhi, LIU He, et al. Concept and application of "sweet spot" in shale oil[J]. Acta Petrolei Sinica, 2023, 44(1): 1-13.