Characteristics and significance of supergene karst of the Upper Permian Changxing Formation in Puguang Gasfield,Sichuan Basin
Yang Fei1, Zhang Hong-An1, Wang Xue-Jun1, Peng Jun1, Mo Jian-Wu1, Zhuo Se-Qiang1, Zeng Zheng-Qing1, Zhou Kai1, Wang Yun-Suo1, Wei Ming-Yang2, Li Zong-Feng2, Lu Kai2
1 Exploration and Development Research Institute,Sinopec Zhongyuan Oilfield Company,Zhengzhou 450046,China; 2 College of Geosciences,China University of Petroleum(Beijing),Beijing 102249,China;
Abstract There is a great dispute in understanding the contact relationship between the Permian and Triassic, and origins of the karst of Changxing Formation in Sichuan Basin for a long time. Through the analysis of field outcrops, drilling, cores, imaging logging, C-O isotope and other data, this paper finds that large-scale karst gullies, karst caves, cystic karst caves and karst breccias occurred in Changxing Formation of Puguang Gasfield. The carbon isotopes of the dissolved limestone in Changxing Formation were negatively excursed near the Permian-Triassic boundary. The top of Changxing Formation is an obvious unconformity, and the karst facies variations are obvious on the imaging logging map. Furthermore, at the top of Changxing Formation, some strata is missing. According to the comprehensive analysis, the results reveal that the supergene karst had occurred in the Changxing Formation of Puguang Gasfield, and that the major factor causing the supergene karst is the great regression event at late Changxing Stage. Changxing Formation had been modified by the supergene karst for a long time. In addition to the reef-bank reservoirs at the edge of the platform, the interior of the platform and the up-slope at the front of the platform where the reef-bank is not occurred are also the favourable areas to search for the unconformity karst reservoirs.
Fund:Co-funded by the National Key Research and Development Programs of China (Nos.2017YFC0603104, 2018YFC0604304),Sinopec Science and Technology Major Project (No. P16108)
About author: Yang Fei,born in 1987,is a postdoctoral fellow of Sinopec Zhongyuan Oilfield Company. He is mainly engaged in carbonate lithofacies paleogeography and karst. E-mail: jerryford2@126.com.
Cite this article:
Yang Fei,Zhang Hong-An,Wang Xue-Jun et al. Characteristics and significance of supergene karst of the Upper Permian Changxing Formation in Puguang Gasfield,Sichuan Basin[J]. JOPC, 2019, 21(6): 901-912.
Yang Fei,Zhang Hong-An,Wang Xue-Jun et al. Characteristics and significance of supergene karst of the Upper Permian Changxing Formation in Puguang Gasfield,Sichuan Basin[J]. JOPC, 2019, 21(6): 901-912.
[1] 鲍志东,金之钧,孙龙德,王招明,王清华,张清海,时晓章,李伟,吴茂炳,顾乔元,武新民,张宏伟. 2006. 塔里木地区早古生代海平面波动特征: 来自地球化学及岩溶的证据. 地质学报, 80(3): 366-373. [Bao Z D,Jin Z J,Sun L D,Wang Z M,Wang Q H,Zhang Q H,Shi X Z,Li W,Wu M B,Gu Q Y,Wu X M,Zhang H W.2006. Sea-level fluctuation of the Tarim area in the Early Paleozoic: Respondence from geochemistry and karst. Acta Geologica Sinica, 80(3): 366-373] [2] 陈景山,李忠,王振宇,谭秀成,李凌,马青. 2008. 塔里木盆地奥陶系碳酸盐岩古岩溶作用于储层分布. 沉积学报, 25(6): 858-868. [Chen J S,Li Z,Wang Z Y,Tan X C,Li L,Ma Q.2008. Paleokarstification and reservoir distribution of Ordovician carbonates in Tarim Basin. Acta Sedimentologica Sinica, 25(6): 858-868] [3] 杜永灯,张磊,王伟洁,冯庆来. 2009. 浙江湖州黄芝山剖面长兴组顶部古剥蚀面的识别及其地质意义. 地质论评, 55(4): 503-508. [Du Y D,Zhang L,Wang W J,Feng Q L.2009. Paleo-weathering crust at the top of the Changxing Formation in Huangzhishan Section,Huzhou,Zhejiang,and its geological significance. Geological Review, 55(4): 503-508] [4] 黎虹玮,唐浩,苏成鹏,陈虹宇,刘宏,胡广,李凌,谭秀成. 2015. 四川盆地东部涪陵地区上二叠统长兴组顶部风化壳特征及地质意义. 古地理学报, 17(4): 477-492. [Li H W,Tang H,Su C P,Chen H Y,Liu H,Hu G,Li L,Tan X C.2015. Characteristics of weathering crust at top of Upper Permian Changxing Formation in Fuling area,eastern Sichuan Basin and its geological significance. Journal of Palaeogeography(Chinese Edition), 17(4): 477-492] [5] 罗冰,谭秀成,李凌,刘宏,夏吉文,杜本强,刘晓光,牟晓慧. 2010. 蜀南地区长兴组顶部岩溶不整合的发现及其油气地质意义. 石油学报, 31(3): 408-414. [Luo B,Tan X C,Li L,Liu H,Xia J W,Du B Q,Liu X G,Mou X H.2010. Discovery and geologic significance of paleokarst unconformity between Changxing Formation and Feixianguang Formation in Shunan area of Sichuan Basin. Acta Petrolei Sinica, 31(3): 408-414] [6] 马永生,牟传龙,郭旭升,谭钦银,余谦. 2006. 四川盆地东北部长兴期沉积特征与沉积格局. 地质论评, 52(1): 25-31. [Ma Y S,Mou C L,Guo X S,Tan Q Y,Yu Q.2006. Characteristics and framework of the Changxingian sedimentation in the Northeastern Sichuan Basin. Geological Review, 52(1): 25-31] [7] 马永生,牟传龙,谭钦银,余谦,王瑞华. 2007. 达县—宣汉地区长兴组—飞仙关组礁滩相特征及其对储层的制约. 地学前缘, 14(1): 182-192. [Ma Y S,Mou C L,Tan Q Y,Yu Q,Wang R H.2007. Reef-bank features of Permian Changxing Formation and Triassic Feixianguan Formation in the Daxian-Xuanhan area,Sichuan Province,South China and constraint for the reservoirs of natural gas. Earth Science Frontiers, 14(1): 182-192] [8] 马永生. 2008. 普光气田天然气地球化学特征及气源探讨. 天然气地球科学, 19(1): 1-7. [Ma Y S.2008. Geochemical characteristics and origin of natural gases from Puguang Gas Field on eastern Sichuan Basin. Natural Gas Geoscience, 19(1): 1-7] [9] 王宝清,张金亮. 1996. 古岩溶的形成条件及其特征. 西安石油学院学报: 自然科学版, 11(4): 8-10. [Wang B Q,Zhang J L.1996. The forming conditions and characteristics of palaeokarst. Journal of Xi’an Petroleum Institute: Natural Science Edition, 11(4): 8-10] [10] 王春梅,王春连,刘成林,龙胜祥,吴世祥,张军涛. 2011. 四川盆地东北部长兴期沉积相、沉积模式及其演化. 中国地质, 38(3): 594-609. [Wang C M,Wang C L,Liu C L,Long S X,Wu S X,Zhang J T.2011. Sedimentary facies,sedimentary model and evolution of Changxing Formation in northeast Sichuan Basin. Geology in China, 38(3): 594-609] [11] 王一刚,张静,杨雨,刘划一,余晓锋. 1997. 四川盆地东部上二叠统长兴组生物礁气藏形成机理. 海相油气地质,5(1/2): 145-152. [Wang Y G,Zhang J,Yang Y,Liu H Y,Yu X F.1997. Formation mechanism of reefs gas pools in the Changxing Formation in eastern Sichuan Basin. Marine Origin Petroleum Geology,5(1/2): 145-152] [12] 吴亚生,姜红霞,廖太平. 2006. 重庆老龙洞二叠系—三叠系界线地层的海平面下降事件. 岩石学报, 22(9): 2405-2412. [Wu Y S,Jiang H X,Liao T P.2006. Sea-level drops in the Permian-Triassic boundary section at Laolongdong,Chongqing,Sichuan Province. Acta Petrologica Sinica, 22(9): 2405-2412] [13] 夏明军,曾大乾,邓瑞健,姜贻伟,毕建霞,靳秀菊,谭国华,苗箐. 2009. 普光气田长兴组台地边缘礁、滩沉积相及储层特征. 天然气地球科学, 20(4): 549-562. [Xia M J,Zeng D Q,Deng R J,Jiang Y W,Bi J X,Jin X J,Tan G H,Miao Q.2009. Formation conditions and distribution rules of lithologic reservoirs in the Southwest margin of Qikou sag,and some representative examples. Natural Gas Geoscience, 20(4): 549-562] [14] 杨晓宁,沈安江,陈子炓,陈俊明. 2002. 中国南方二叠纪生物礁油气系统成因类型. 石油学报, 23(3): 6-10. [Yang X N,Shen A J,Chen Z L,Chen J M.2002. Genetic types for petroliferous system of organic reefs in the Permian System of South China. Acta Petrolei Sinica, 23(3): 6-10] [15] Chen J,Beatty T W,Henderson C M,Rowe H.2009. Conodont biostratigraphy across the Permian-Triassic boundary at the Dawen section,Great Bank of Guizhou Province,South China: Implications for the Late Permian extinction and correlation with Meishan. Journal of Asian Earth Sciences, 36(6): 442-458. [16] Enzo F,Perri M C,Posenato R.2007. Environmental and biotic changes across the Permian-Triassic boundary in western Tethys: The Bulla parastratotype,Italy. Global and Planetary Chang, 55(1): 109-135. [17] Ezaki Y,Liu J B,Adach N.2003. Earliest Triassic microbialite micro-tomegastructures in the Huaying area of Sichuan Province,South China: Implications for the nature of oceanic conditions after the end-Permian extinction. Palaios, 18(4-5): 388-402. [18] Hallam A,Wignall P B.1999. Mass extinctions and sea-level changes. Earth-Science Reviews, 48(4): 217-250. [19] Krull E S,Lehrmann D J,Druke D,Kessel B,Yu Y Y, Li R X.2004. Stable carbon isotope stratigraphy across the Permian-Triassic boundary in shallow marine carbonate platforms,Nanpanjiang Basin,south China. Palaeogeography,Palaeoclimatology,Palaeoecology, 204(3): 297-315. [20] Lehrmann D J,Payne J L,Felix S V,Dillett P M,Wang H,Yu Y,Wei J.2003. Permian-Triassic boundary sections from shallow-marine carbonate platforms of the Nanpanjiang Basin,south China: Implications for oceanic conditions associated with the end-Permian extinction and its aftermath. Palaios, 18(2): 138-152. [21] Song H J,Tong J N,Chen Z Q,Yang H,Wang Y B.2009. End-Permian mass extinction of foraminifers in the Nanpanjiang Basin,South China. Journal Information, 83(5): 718-738. [22] Sun D Y,Tong J N,Xiong Y N,Tian L,Yin H F.2012. Conodont biostratigraphy and evolution across Permian-Triassic boundary at Yangou Section,Leping,Jiangxi Province,South China. Journal of Earth Science, 23(3): 311-325. [23] Wu Y S,Fan J S,Jiang H X,Yang W.2007. Extinction pattern of reef ecosystems in lates Permian. Chinese Science Bulletin, 52(4): 512-520. [24] Wu Y S,Jiang H X,Fan J S.2010. Evidence for sea-level falls in the Permian-Triassic transition in the Ziyun area,South China. Geological Journal, 45(2-3): 170-185. [25] Yang F,Bao Z D,Zhang D M,Jia X,Xiao J.2017. Carbonate secondary porosity development in a polyphaser paleokarst from Precambrian system: Upper Sinian examples,North Tarim Basin,Northwest China. Carbonates and Evaporites, 32: 243-256. [26] Yin H F,Jiang H S,Xia W C,Feng Q L.2014. The end-Permian regression in South China and its implication on mass extinction. Earth-Science Reviews, 137: 19.
