Salt Accumulation, Potassium Formation Mechanism and Enrichment Model of Triassic in Northeast Sichuan Basin
-
摘要:
川东北地区三叠系发育巨厚的蒸发岩层，并赋存优质的深层富钾卤水. 因构造沉积条件的整体差异，川东北富钾卤水的成因机制与富集规律未有详尽研究. 以“气钾兼探”为指导思想，综合利用野外露头-岩心-测井等资料，对川东北地区三叠系蒸发岩分布规律以及岩相古地理演化进行分析，明确了膏盐盆在T1j4-5-T2l1期间规模逐渐缩小、向SW逐渐迁移的分布规律. 结合岩心与卤水地球化学分析，判定川东北地区富钾卤水成因机制以海水蒸发浓缩与表层淡水淋滤为主，深部水岩反应较弱. 结合井震分析，提出富钾卤水具备“膏盆盐盆控卤、孔隙裂缝储卤、背斜核部富卤”的富集规律. 综合认为富钾卤水为“构造-沉积”双重因素控制的“次级深凹”富集模式.
Abstract:During the Triassic period, the Northeast Sichuan developed a huge evaporative salt layer and accumulated high quality deep potassium-rich brine. Due to the overall differences in tectonic depositional conditions, the genetic mechanism and enrichment rules of potassium-rich brine in Northeast Sichuan Basin have not been studied in detail. In this study it takes "gas-potassium exploration" as the guiding ideology, and comprehensively utilizes the field outcrop-core-logging data to analyze the distribution and lithofacies paleogeographic evolution of the Triassic evaporite in the Northeast Sichuan basin, and finally it shows the size of salt basin in Northeast Sichuan decreased gradually and migrated to southwest during T1j4-5-T2l1. Combined with core and brine geochemical analysis, it is concluded that the genesis mechanism of potassium-rich brine in Northeast Sichuan is mainly seawater evaporation-concentration mechanism and surface fresh water leaching mechanism, and the deep water-rock reaction is weak. Combined with well logging and seismic interpretation, it is proposed that the potassium-rich brine has the enrichment rule of "controlling brine by the gypsum basin and salt basin; storing brine in the pores and fractures; enriching brine in the core of anticline". It is considered that the potassium-rich brine is a "secondary deep depression" enrichment model controlled by "structure-deposition" dual factors.
-
图 1 研究区构造位置 (a, b) 和综合柱状图 (c)
图a据龚大兴等（2014）修改；图b据李杰（2018）修改
Fig. 1. The structural location (a, b) and comprehensive histogram (c) of the study area
图 2 川东北地区三叠纪典型岩心、野外露头及镜下薄片特征
a. A井，泥微晶灰岩，T2l1；b. 营24S井，白云质灰岩，T1j4-5；c. A井，微晶白云岩，T2l1；d. A井，灰质白云岩，T2l1；e. A井，膏质白云岩，T2l1；f. 龙岗001-12井，颗粒白云岩，T1j4-5；g. 营24S井，石膏，T1j4-5；h. 四川广安，谢家槽剖面膏溶角砾岩，T1j4-5；i. 营24S井，盐岩，T1j4-5
Fig. 2. Characteristics of typical Triassic cores, outcrops and microscopic thin sections in Northeast Sichuan
图 3 嘉四五段 (a、b) 和雷一段 (c、d) 蒸发岩等厚图及岩相古地理图
Fig. 3. The evaporite thickness map and lithofacies palaeogeographic map of T1j4-5 (a, b) and T2l1 (c, d)
图 4 川东北富钾卤水海水蒸发浓缩机制
Fig. 4. Evaporation and concentration mechanism of potassium-rich brine in Northeast Sichuan
图 5 川东北富钾卤水淡水淋滤机制
Fig. 5. The leaching mechanism of potassium-rich brine in Northeast Sichuan
图 6 川东北宣汉地区A井样品C、O同位素和古水温
C、O同位素数据部分引自Zhang et al.（2018）
Fig. 6. C, O isotopes and paleowater temperature of samples from Well A in Xuanhan area, Northeast Sichuan
图 7 川东北富钾卤水深部水岩反应机制
Fig. 7. The reaction mechanism of deep water rock of potassium-rich brine in Northeast Sichuan
图 8 A井原始地幔标准化微量元素蛛网图
Fig. 8. The primitive mantle-normalized trace element spider diagram of Well A
图 9 川东北地区岩石微观特征
a. 普光5井×4（+），井深2 675.2 m，针孔砂屑云岩，铸模孔、粒内溶孔；b. 普光8井×2（+），井深2 366 m，泥粉晶云岩，晶间溶孔；c. 普光11井×10（+），井深3 182.6 m，亮晶砂屑灰质云岩，粒间、粒内溶孔；d. A井×10（‒），井深3 338.6 m，粒间溶孔；e. A井×10（‒），井深3 338.6 m，微裂隙填充及填充物溶蚀；f. A井×10（+），井深3 425.7 m，微晶白云岩，裂缝
Fig. 9. Microcosmic characteristics of rocks in Northeast Sichuan region
图 11 川东北三叠系富钾卤水“次级深凹”聚盐模式
Fig. 11. The "secondary deep concave" polysalt pattern of Triassic potassium-rich brine in Northeast Sichuan
表 1 A井富钾卤水分析结果
Table 1. Analysis results of potassium-rich brine in Well A
元素 浓度（mg/L） K+ 31 961.25 Na+ 88 217.50 Mg2+ 1 016.48 Cl‒ 210 365.11 Br‒ 1 342.51 SO42‒ 418.08 注：深藏卤水工业开采标准参考《矿产地质勘查规范DZ/T0212 4⁃2020》：K+/Cl-为0.5%~1%；Br-为50~60 mg/L. 
下载: 导出CSV
表 2 A井岩心微量元素含量（μg/g）
Table 2. Contents of trace elements in Well A core (μg/g)
样品数 参数 U Ta Sr Th Hf Sm 19 最大值 9 523.81 142.77 11.14 560.55 12.57 11.41 最小值 226.76 29.74 1.09 13.84 2.09 0.46 平均值 3 974.22 74.52 4.56 174.76 4.96 3.71
下载: 导出CSV
表 3 宣汉‒达州地区雷口坡组和嘉陵江组储层孔渗数据
Table 3. Statistical data of reservoir porosity and permeability of Leikoupo Formation and Jialingjiang Formation in Xuanhan⁃ Dazhou district
系 组 层位 孔隙度（%） 渗透率（10-3 µm2) 平均孔隙度（%） 平均渗透率（10-3 µm2） 储层类别划分 三叠系 雷口坡组 雷三段 2.46 < 0.1 2.57 0.1 Ⅰ类：POR≥12%Ⅱ类：6%≤POR < 12%Ⅲ类：3%≤POR < 6% 雷二段 3.02 < 0.1 雷一段 2.24 < 0.1 嘉陵江组 嘉五段 2.26 \ 3.97 0.642 嘉四段 5.05 0.012 嘉三段 2.36 \ 嘉二段 4.21 0.667 嘉一段 3.12 \
下载: 导出CSV
-
Chen, A.Q., Wang, L.C., Ji, G.J., et al., 2015. Evaporatic Environment and the Concentration Model of Potash in the Early-Middle Triassic, Northeastern Sichuan Basin. Acta Petrologica Sinica, 31(9): 2757-2769 (in Chinese with English abstract). Dong, W.Y., 2012. Reservoir Characteristics of Changxing Formation of Permian in Xuanhan, Northeast Sichuan (Dissertation). Chengdu University of Technology, Chengdu (in Chinese with English abstract). Gong, D.X., 2016. The Triassic Salt-Forming Environment, Potash-Forming Conditions and Genetic Mechanism in Sichuan Basin (Dissertation). Chengdu University of Technology, Chengdu (in Chinese with English abstract). Gong, D.X., Zhou, J.Y., Chen, K.G., et al., 2014. Identification of the Potassium-Rich Member in Carbonate Platform and Its Response to the Gamma Ray Well Logging from the Perspective of Cyclostratigraphy: A Case Study in Triassic of Guangan Area, in the Central Sichuan Basin. Geological Journal of China Universities, 20(2): 230-238 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-GXDX201402007.htm Hou, E.G., Gao, J.H., Wang, X.L., et al., 2015. Geochemical Characteristics and Environmental Significance of the Upper Triassic Riganpeicuo Formation in Gaize, Tibet. Bulletin of Mineralogy, Petrology and Geochemistry, 34(3): 556-563 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-KYDH201503016.htm Huang, X., 2013. The Enrichment Regularity of Triassic Potassium-Rich Brines of the Salt-Bearing Sichuan Basin (Dissertation). China University of Geosciences, Beijing (in Chinese with English abstract). Li, J., 2018. Formation and Preservation Mechanism of the High-Quality Dolostone Reservoir in the Feixianguan Formation, Xuanhan-Daxian Area (Dissertation). China University of Geosciences, Wuhan (in Chinese with English abstract). Li, T.W., Tan, H.B., Fan, Q.S., 2006. Hydrochemical Characteristics and Origin Analysis of the Underground Brines in West Qaidam Basin. Journal of Salt Lake Research, 14(4): 26-32 (in Chinese with English abstract). Lin, L.B., Chen, H.D., Dan, Y., et al., 2012. Characteristics and Genesis of Middle Cambrian Gypsum Rock in Sichuan Basin. Journal of Jilin University (Earth Science Edition), 42(S2): 95-103 (in Chinese with English abstract). http://www.cnki.com.cn/Article/CJFDTotal-CCDZ2012S2012.htm Lin, Y.T., Cao, S.X., 2001. Potassium-Rich Brines Resources in Sichuan Province and Its Exploitation Prospect. Conservation and Utilization of Mineral Resources, (4): 14-17 (in Chinese with English abstract). Lin, Y.T., Chen, S.L., 2008. Discussion on the Evaporite Generating Modes, Salt Forming Mechanism and Potassium-Hunting Prospect of Lower-Middle Triassic in Sichuan Basin. Journal of Salt Lake Research, 16(3): 1-10 (in Chinese with English abstract). Liu, C.L., Wu, C.H., Wang, L.C., et al., 2016. Advance in the Study of Forming Condition and Prediction of Potash Deposits of Marine Basins in China's Small Blocks: Review. Acta Geoscientica Sinica, 37(5): 581-606 (in Chinese with English abstract). http://www.researchgate.net/publication/313388676_Advance_in_the_study_of_forming_condition_and_prediction_of_potash_deposits_of_marine_basins_in_China's_small_blocks_Review Liu, C.L., Zhao, Y.J., Fang, X.M., et al., 2015. Plate Tectonics Control on the Distribution and Formation of the Marine Potash Deposits. Acta Geologica Sinica, 89(11): 1893-1907 (in Chinese with English abstract). Qian, Y.X., Zou, Y.R., Chen, Q.L., et al., 2005. Geological and Geochemical Implications for Multi-Period and Origin of Carbonate Karstification in the Northwestern Tazhong: Taking Well Zhong 1 as an Example. Acta Sedimentologica Sinica, 23(4): 596-603 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-CJXB200504005.htm Su, N., Yang, W., Yuan, B.G., et al., 2021. Structural Features and Deformation Mechanism of Transtensional Faults in Himalayan Period, Sichuan Basin. Earth Science, 46(7): 2362-2378 (in Chinese with English abstract). Wang, S.C., 2011. Potassium-Rich Brine in the Middle Triassic Enrichment Model and the Prediction of Favorable in the Southern Section of Western Sichuan Depression (Dissertation). Chengdu University of Technology, Chengdu (in Chinese with English abstract). Wu, S.H., Chen, K., Li, X.G., et al., 2020. Discovery of the Large Early Platform Margin of Upper Sinian Dengying Formation in Central and Northeast Sichuan Basin and Its Implications for Hydrocarbon Exploration. Earth Science, 45(3): 998-1012 (in Chinese with English abstract). Xu, G.S., Chen, M.L., Liu, W., et al., 2012. Lithofacies Palaeogeography and Forecast of Potassium-Rich Brine of Leikoupo Formation in Western Sichuan. Mineral Deposits, 31(2): 309-322 (in Chinese with English abstract). Yang, Y.R., Zhang, Y., Xie, C., et al., 2019. Hydrothermal Action of Middle Permian Qixia Formation in Northwestern Sichuan Basin and Its Effect on Reservoirs. Lithologic Reservoirs, 31(6): 44-53 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTotal-YANX201906005.htm Zhang, B., Yang, K., Wang, X.B., et al., 2018. Salt‐Gathering and Potassium Formation of Potassium‐Rich Brine during the Triassic in the Sichuan Basin, China. Acta Geologica Sinica (English Edition), 92(6): 2233-2250. https://doi.org/10.1111/1755-6724.13725 Zhang, G.R., 1997. Geological Characteristics and Emplacement Mechanism of Caledonian Intrusive Rocks in Jianping, Liaoning. Liaoning Geology, (1): 9-13 (in Chinese with English abstract). http://en.cnki.com.cn/Article_en/CJFDTOTAL-LOAD701.001.htm Zheng, M.P., Hou, X.H., Yu, C.Q., et al., 2015. The Leading Role of Salt Formation Theory in the Breakthrough and Important Progress in Potash Deposit Prospecting. Acta Geoscientica Sinica, 36(2): 129-139 (in Chinese with English abstract). http://www.zhangqiaokeyan.com/academic-journal-cn_acta-geoscientica-sinica_thesis/0201253091984.html Zheng, M.P., Qi, W., Zhang, Y.S., 2006. Present Situation of Potash Resources and Direction of Potash Search in China. Geological Bulletin of China, 25(11): 1239-1246 (in Chinese with English abstract). Zheng, M.P., Yuan, H.R., Zhang, Y.S., et al., 2010. Regional Distribution and Prospects of Potash in China. Acta Geologica Sinica, 84(11): 1523-1553 (in Chinese with English abstract). Zhou, J.Y., Gong, D.X., Li, M., 2015. The Characteristic of Evaporite, Migration of Salt Basins and Its Tectonic Control in Triassic Sichuan Basin. Acta Geologica Sinica, 89(11): 1945-1952 (in Chinese with English abstract). http://www.en.cnki.com.cn/Article_en/ http://search.cnki.net/down/default.aspx?filename=DZXE201511006&dbcode=CJFD&year=2015&dflag=pdfdown Zhou, X., Cao, Q., Yin, F., et al., 2015. Characteristics of the Brines and Hot Springs in the Triassic Carbonates in the High and Steep Fold Zone of the Eastern Sichuan Basin. Acta Geologica Sinica, 89(11): 1908-1920 (in Chinese with English abstract). http://www.en.cnki.com.cn/Article_en/ http://search.cnki.net/down/default.aspx?filename=DZXE201511003&dbcode=CJFD&year=2015&dflag=pdfdown 陈安清, 王立成, 姬广建, 等, 2015. 川东北早-中三叠世聚盐环境及海水浓缩成钾模式. 岩石学报, 31(9): 2757-2769. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB201509023.htm 董文玉, 2012. 川东北宣汉地区二叠系长兴组储层特征研究. 成都: 成都理工大学. 龚大兴, 2016. 四川盆地三叠纪成盐环境、成钾条件及成因机制. 成都: 成都理工大学. 龚大兴, 周家云, 陈科贵, 等, 2014. 海相碳酸盐台地含钾层段旋回地层学响应和识别——以川中广安地区三叠系为例. 高校地质学报, 20(2): 230-238. doi: 10.3969/j.issn.1006-7493.2014.02.007 侯恩刚, 高金汉, 王训练, 等, 2015. 西藏改则上三叠统日干配错组碳酸盐岩地球化学特征及沉积环境意义. 矿物岩石地球化学通报, 34(3): 556-563. doi: 10.3969/j.issn.1007-2802.2015.03.012 黄熙, 2013. 四川盆地三叠纪盐盆富钾卤水富集规律. 北京: 中国地质大学. 李杰, 2018. 宣汉-达县地区飞仙关组优质白云岩储层形成与保存机制(博士学位论文). 武汉: 中国地质大学. 李廷伟, 谭红兵, 樊启顺, 2006. 柴达木盆地西部地下卤水水化学特征及成因分析. 盐湖研究, 14(4): 26-32. doi: 10.3969/j.issn.1008-858X.2006.04.005 林良彪, 陈洪德, 淡永, 等, 2012. 四川盆地中寒武统膏盐岩特征与成因分析. 吉林大学学报(地球科学版), 42(S2): 95-103. https://www.cnki.com.cn/Article/CJFDTOTAL-CCDZ2012S2012.htm 林耀庭, 曹善行, 2001. 四川卤水钾资源及其开发利用前景. 矿产保护与利用, (4): 14-17. doi: 10.3969/j.issn.1001-0076.2001.04.005 林耀庭, 陈绍兰, 2008. 论四川盆地下、中三叠统蒸发岩的生成模式、成盐机理及找钾展望. 盐湖研究, 16(3): 1-10. https://www.cnki.com.cn/Article/CJFDTOTAL-YHYJ200803000.htm 刘成林, 吴驰华, 王立成, 等, 2016. 中国陆块海相盆地成钾条件与预测研究进展综述. 地球学报, 37(5): 581-606. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXB201605008.htm 刘成林, 赵艳军, 方小敏, 等, 2015. 板块构造对海相钾盐矿床分布与成矿模式的控制. 地质学报, 89(11): 1893-1907. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201511002.htm 钱一雄, 邹远荣, 陈强路, 等, 2005. 塔里木盆地塔中西北部多期、多成因岩溶作用地质-地球化学表征——以中1井为例. 沉积学报, 23(4): 596-603. doi: 10.3969/j.issn.1000-0550.2005.04.006 苏楠, 杨威, 苑保国, 等, 2021. 四川盆地喜马拉雅期张扭性断裂构造特征及形成机制. 地球科学, 46(7): 2362-2378. doi: 10.3799/dqkx.2020.202 王帅成, 2011. 川西坳陷南段中三叠统富钾卤水富集模式及有利区预测. 成都: 成都理工大学. 吴仕虎, 陈康, 李小刚, 等, 2020. 川中-川东北地区上震旦统灯影组大型早期台缘带的发现及其油气勘探意义. 地球科学, 45(3): 998-1012. doi: 10.3799/dqkx.2019.293 徐国盛, 陈美玲, 刘为, 等, 2012. 川西地区雷口坡组岩相古地理与富钾卤水预测. 矿床地质, 31(2): 309-322. doi: 10.3969/j.issn.0258-7106.2012.02.011 杨雨然, 张亚, 谢忱, 等, 2019. 川西北地区中二叠统栖霞组热液作用及其对储层的影响. 岩性油气藏, 31(6): 44-53. https://www.cnki.com.cn/Article/CJFDTOTAL-YANX201906005.htm 张国仁, 1997. 利用沉积地球化学特征分析古环境及海平面变化——以鲁西东部中下寒武统为例. 辽宁地质, (1): 9-13. https://www.cnki.com.cn/Article/CJFDTOTAL-LOAD701.001.htm 郑绵平, 侯献华, 于常青, 等, 2015. 成盐理论引领我国找钾取得重要进展. 地球学报, 36(2): 129-139. https://www.cnki.com.cn/Article/CJFDTOTAL-DQXB201502001.htm 郑绵平, 齐文, 张永生, 2006. 中国钾盐地质资源现状与找钾方向初步分析. 地质通报, 25(11): 1239-1246. doi: 10.3969/j.issn.1671-2552.2006.11.001 郑绵平, 袁鹤然, 张永生, 等, 2010. 中国钾盐区域分布与找钾远景. 地质学报, 84(11): 1523-1553. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201011002.htm 周家云, 龚大兴, 李萌, 2015. 四川盆地三叠纪蒸发岩特征、盐盆迁移及其构造控制. 地质学报, 89(11): 1945-1952. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201511006.htm 周训, 曹琴, 尹菲, 等, 2015. 四川盆地东部高褶带三叠系地层卤水和温泉的地球化学特征及成因. 地质学报, 89(11): 1908-1920. https://www.cnki.com.cn/Article/CJFDTOTAL-DZXE201511003.htm -
点击查看大图
计量
- 文章访问数: 893
- HTML全文浏览量: 662
- PDF下载量: 68
- 被引次数: 0
