Dissolution Stage and Pattern of Reservoirs in Maokou Formation in Yunjin Area, Southern Sichuan Basin

doi:10.7657/XJPG20220505

Abstract

Abstract:

In order to determine the genesis of the carbonate reservoirs in the Middle Permian Maokou formation in Yunjin area, southern Sichuan basin, the dissolution stage and mechanism were investigated through core and thin section observations, petrological analysis and isotopic geochemical analysis. There are three stages of dissolution in the reservoirs of the Maokou formation in the study area: (1) atmospheric water karstification in the supergene stage, with atmospheric precipitation as the karstification fluid and the fractures formed in the Dongwu movement period as the flow channels, which showed the transformation from fractures to dissolution fractures/vugs and karst cavities, mainly under the control of unconformity surface and paleomorphology; (2) hydrothermal dissolution in the early diagenetic stage, when the deep mantle-derived hydrothermal fluid in the post-magmatic stage related to the eruption of the Emeishan basalt moved up along the fault to the interior of the Maokou formation and reformed the formation, and saddle-shaped dolomite was developed; and (3) burial dissolution in the late diagenetic stage, when the dissolution fluid was mainly the mixed acid fluid composed of the fluid in Permian carbonate rock and the fluid in mudstone diagenetic transition, and the flow channels were mainly the fractures and stylolite formed in the Yanshan movement period, with dissolution fractures/vugs developed along fractures and stylolite. On the whole, the atmospheric water karstification in the supergene stage is the decisive diagenesis for the formation of the reservoirs in the study area, and the hydrothermal dissolution in the early diagenetic stage and the burial dissolution in the late diagenetic stage allowed the formation of a small amount of dissolution pores/vugs and dissolution fractures, which could improve the storage performance of the reservoirs.

Key words: Sichuan basin, Yunjin area, Maokou formation, reservoir, dissolution, dissolution stage, isotopic geochemistry

CLC Number:

TE122.221

HE Zhao, GAO Zhaolong, LI Guorong, HE Sai, MO Guochen, TIAN Jiaqi, LI Xiaoxiao. Dissolution Stage and Pattern of Reservoirs in Maokou Formation in Yunjin Area, Southern Sichuan Basin[J]. Xinjiang Petroleum Geology, 2022, 43(5): 537-545.

Figures/Tables 8

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References 32

[1]	张健, 周刚, 张光荣, 等. 四川盆地中二叠统天然气地质特征与勘探方向[J]. 天然气工业, 2018, 38(1):10-20.
	ZHANG Jian, ZHOU Gang, ZHANG Guangrong, et al. Geological characteristics and exploration orientation of Mid-Permian natural gas in the Sichuan basin[J]. Natural Gas Industry, 2018, 38(1):10-20.
[2]	黄士鹏, 江青春, 冯庆付, 等. 川南地区中二叠统茅口组岩溶储集层类型与分布规律[J]. 石油勘探与开发, 2019, 46(2):281-289.
	HUANG Shipeng, JIANG Qingchun, FENG Qingfu, et al. Type and distribution of Mid-Permian Maokou formation karst reservoirs in southern Sichuan basin,SW China[J]. Petroleum Exploration and Development, 2019, 46(2):281-289.
[3]	桑琴, 未勇, 程超, 等. 蜀南地区二叠系茅口组古岩溶地区水系分布及岩溶地貌单元特征[J]. 古地理学报, 2012, 4 (3):393-402.
	SANG Qin, WEI Yong, CHENG Chao, et al. Distribution of palaeokarst water system and palaeogeomorphic unit characteristics of the Permian Maokou formation in southern Sichuan province[J]. Journal of Palaeogeography, 2012, 4 (3):393-402.
[4]	江青春, 胡素云, 汪泽成, 等. 四川盆地茅口组风化壳岩溶古地貌及勘探选区[J]. 石油学报, 2012, 33 (6):949-960. doi: 10.7623/syxb201206005
	JIANG Qingchun, HU Suyun, WANG Zecheng, et al. Paleokarst landform of the weathering crust of Middle Permian Maokou formation in Sichuan basin and selection of exploration regions[J]. Acta Petrolei Sinica, 2012, 33 (6):949-960. doi: 10.7623/syxb201206005
[5]	李双建, 杨天博, 韩月卿, 等. 四川盆地中二叠统热液白云石化作用及其储层改造意义[J]. 石油与天然气地质, 2021, 42 (6):1 265-1 280.
	LI Shuangjian, YANG Tianbo, HAN Yueqing, et al. Hydrothermal dolomitization and its role in improving Middle Permian reservoirs for hydrocarbon accumulation,Sichuan basin[J]. Oil & Gas Geology, 2021, 42 (6):1 265-1 280.
[6]	任海侠, 林小兵, 刘叶, 等. 川西南二叠系茅口组一段滑石化特征及其形成机理:以A1井茅一段样品为例[J]. 石油实验地质, 2021, 43 (6):1 038-1 047.
	REN Haixia, LIN Xiaobing, LIU Ye, et al. Characteristics and formation mechanism of talc in Permian Maokou formation,southwestern Sichuan basin:a case study of First member of Maokou formation in Well A1[J]. Petroleum Geology & Experiment, 2021, 43 (6):1 038-1 047.
[7]	陈轩, 赵文智, 刘银河, 等. 川西南地区中二叠统热液白云岩特征及勘探思路[J]. 石油学报, 2013, 34 (3):460-466. doi: 10.7623/syxb201303006
	CHEN Xuan, ZHAO Wenzhi, LIU Yinhe, et al. Characteristics and exploration strategy of the Middle Permian hydrothermal dolomite in southwestern Sichuan basin[J]. Acta Petrolei Sinica, 2013, 34 (3):460-466. doi: 10.7623/syxb201303006
[8]	任梦怡, 汪泽成, 江青春, 等. 川南地区中二叠统茅口组碳酸盐岩储层孔隙特征与储层成因[J]. 东北石油大学学报, 2021, 45 (3):32-43.
	REN Mengyi, WANG Zecheng, JIANG Qingchun, et al. The carbonate reservoir charactertics and pore genesis in the Middle Permian Maokou formation,southern Sichuan basin[J]. Journal of Northeast Petroleum University, 2021, 45 (3):32-43.
[9]	黎荣, 胡明毅, 杨威, 等. 四川盆地中二叠统沉积相模式及有利储集体分布[J]. 石油与天然气地质, 2019, 40 (2):369-379.
	LI Rong, HU Mingyi, YANG Wei, et al. Sedimentary facies model and favorable reservoir distribution of the Middle Permian in Sichuan basin[J]. Oil & Gas Geology, 2019, 40 (2):369-379.
[10]	肖笛, 谭秀成, 山述娇, 等. 四川盆地南部中二叠统茅口组古岩溶地貌恢复及其石油地质意义[J]. 地质学报, 2014, 88 (10):1 992-2 002.
	XIAO Di, TAN Xiucheng, SHAN Shujiao, et al. The restoration of palaeokarst geomorphology of Middle Permian Maokou formation and its petroleum geological significance in southern Sichuan basin[J]. Acta Geologica Sinica, 2014, 88 (10):1 992-2 002.
[11]	霍飞, 杨西燕, 王兴志, 等. 川西北地区茅口组储层特征及其主控因素[J]. 成都理工大学学报(自然科学版), 2018, 45 (1):45-52.
	HUO Fei, YANG Xiyan, WANG Xingzhi, et al. Characteristics and main controlling factors of the Middle Permian Maokou formation reservoir in northwestern Sichuan basin,China[J]. Journal of Chengdu University of Technology (Science & Technology Edition), 2018, 45 (1):45-52.
[12]	刘树根, 孙玮, 李智武, 等. 四川叠合盆地海相碳酸盐岩油气分布特征及其构造主控因素[J]. 岩性油气藏, 2016, 28 (5):1-17.
	LIU Shugen, SUN Wei, LI Zhiwu, et al. Distribution characteristics of marine carbonate reservoirs and their tectonic controlling factors across the Sichuan superimposed basin[J]. Lithologic Reserviors, 2016, 28 (5):1-17.
[13]	杨柳, 臧殿光, 徐宝亮, 等. 川西南地区茅口组柱状凹陷异常体分布特征及成因[J]. 石油地质与工程, 2020, 34 (5):19-24.
	YANG Liu, ZANG Dianguang, XU Baoliang, et al. Distribution and origin of the columnar sag anomalies of Maokou formation in southwestern Sichuan basin[J]. Petroleum Geology and Engineering, 2020, 34 (5):19-24.
[14]	郭旭升, 黄仁春, 付孝悦, 等. 四川盆地二叠系和三叠系礁滩天然气富集规律与勘探方向[J]. 石油与天然气地质, 2014, 35 (3):295-302.
	GUO Xusheng, HUANG Renchun, FU Xiaoyue, et al. Gas accumulation and exploration direction of the Permian and Triassic reservois of reef-bank facies in Sichuan basin[J]. Oil & Gas Geology, 2014, 35 (3):295-302.
[15]	田雪松. 川东南地区茅口组碳酸盐岩储层地球化学特征研究[D]. 成都: 成都理工大学, 2014:19-23.
	TIAN Xuesong. The geochemical study on the carbonate resevior of the Maokou formation in southeastern Sichuan province[D]. Chengdu: Chengdu University of Technology, 2014:19-23.
[16]	杨柳, 巫芙蓉, 郭鸿喜, 等. 川南YJ向斜区茅口组储层地震预测与主控因素分析[J]. 断块油气田, 2021, 28 (3):363-368.
	YANG Liu, WU Furong, GUO Hongxi, et al. Reservoir seismic prediction and main controlling factors analysis of Maokou formation in YJ syncline area,south Sichuan basin[J]. Fault-Block Oil & Gas Field, 2021, 28 (3):363-368.
[17]	李蓉, 胡昊, 石国山, 等. 川东北阆中地区二叠系茅口组白云岩化成因[J]. 新疆石油地质, 2020, 41(2):127-132.
	LI Rong, HU Hao, SHI Guoshan, et al. Genesis of dolomitization of Permian Maokou formation in Langzhong area,northeastern Sichuan basin[J]. Xinjiang Petroleum Geology, 2020, 41(2):127-132.
[18]	白晓亮, 郗诚, 和源, 等. 四川盆地中二叠统栖霞组层序地层特征及沉积演化模式[J]. 东北石油大学学报, 2020, 44(6):33-42.
	BAI Xiaoliang, XI Cheng, HE Yuan, et al. Sequence stratigraphic characteristics and sedimentary evolution model of the Middle Permian Qixia formation in the Sichuan basin[J]. Journal of Northeast Petroleum University, 2020, 44(6):33-42.
[19]	李源, 陈胜, 王鹏, 等. 川南地区下二叠统茅口组岩溶储集体地震识别[J]. 新疆石油地质, 2021, 42(5):259-540.
	LI Yuan, CHEN Sheng, WANG Peng, et al. Seismic response identification of karst reservoir in Lower Permian Maokou formation in southern Sichuan basin[J]. Xinjiang Petroleum Geology, 2021, 42(5):259-540.
[20]	徐祖新. 川东地区中二叠统茅口组天然气成因及气源[J]. 特种油气藏, 2019, 26 (2):16-22.
	XU Zuxin. Genesis and source of gas in Middle Permian Maokou formation of eastern Sichuan basin[J]. Special Oil & Gas Reserviors, 2019, 26 (2):16-22.
[21]	刘建华, 朱西养, 王四利, 等. 四川盆地地质构造演化特征与可地浸砂岩型铀矿找矿前景[J]. 铀矿地质, 2005, 21(6):321-330.
	LIU Jianhua, ZHU Xiyang, WANG Sili, et al. Geologic-tectonic evolutional characteristics and prospecting potential for ISL-amenable sandstone-type uranium deposits in Sichuan basin[J]. Uranium Geology, 2005, 21(6):321-330.
[22]	胡明毅, 胡忠贵, 魏国齐, 等. 四川盆地茅口组层序岩相古地理特征及储集层预测[J]. 石油勘探与开发, 2012, 39(1):45-55.
	HU Mingyi, HU Zhonggui, WEI Guoqi, et al. Sequence lithofacies paleogeography and reservoir prediction of the Maokou formation in Sichuan basin[J]. Petroleum Exploration and Development, 2012, 39(1):45-55.
[23]	周进高, 姚根顺, 杨光, 等. 四川盆地栖霞组—茅口组岩相古地理与天然气有利勘探区带[J]. 天然气工业, 2016, 36 (4):8-15.
	ZHOU Jingao, YAO Genshun, YANG Guang, et al. Lithofacies palaeogeography and favorable gas exploration zones of Qixia and Maokou Fms in the Sichuan basin[J]. Natural Gas Industry, 2016, 36 (4):8-15.
[24]	王文飞. 四川盆地东部中二叠统茅口组沉积与层序地层特征[J]. 断块油气田, 2015, 22 (2):154-159.
	WANG Wenfei. Sedimentary and sequence stratigraphic characteristics of Middle Permian Maokou formation in eastern Sichuan basin[J]. Fault-Block Oil & Gas Field, 2015, 22 (2):154-159.
[25]	李国蓉, 武恒志, 叶斌, 等. 元坝地区长兴组储层溶蚀作用期次与机制研究[J]. 岩石学报, 2014, 30 (3):709-717.
	LI Guorong, WU Hengzhi, YE Bin, et al. Stages and mechanism of dissolution in Changxing reservoir,Yuanba area[J]. Acta Petrologica Sinica, 2014, 30 (3):709-717.
[26]	JAN V, DAVIN A, KAREM A, et al. ⁸⁷Sr/⁸⁶Sr,δ¹³C and δ¹⁸O evolution of Phanerozoic seawater[J]. Chemical Geology, 1999, 161:59-88. doi: 10.1016/S0009-2541(99)00081-9
[27]	赵金, 冯明友, 沈安江, 等. 川西南中二叠统栖霞组斑马状构造白云岩形成机理:以宝兴五龙剖面为例[J]. 海相油气地质, 2020, 25 (3):223-233.
	ZHAO Jin, FENG Mingyou, SHEN Anjiang, et al. Genesis of zebra dolomite of the Middle Permian Qixia formation in the southwestern Sichuan basin:taking Wulong ourcrop in Baoxing area as an example[J]. Marine Origin Petroleum Geology, 2020, 25 (3):223-233.
[28]	韩晓涛, 鲍征宇, 谢淑云, 等. 四川盆地西南中二叠统白云岩的地球化学特征及其成因[J]. 地球科学, 2016, 41 (1):167-176.
	HAN Xiaotao, BAO Zhengyu, XIE Shuyun, et al. Origin and geochemical characteristics of dolomites in the Middle Permian formation,SW Sichuan basin,China[J]. Earth Science, 2016, 41 (1):167-176.
[29]	PALMER M R, EDMOND J M. The strontium isotope budget of the modern ocean[J]. Earth & Planetary Science Letters, 1989, 92(1):11-26.
[30]	PALMER M R, ELDERFIELD H. Sr isotope composition of sea water over the past 75Ma[J]. Nature, 1985, 314 (11):526-528. doi: 10.1038/314526a0
[31]	黄思静. 上扬子地台区晚古生代海相碳酸盐岩的碳、锶同位素研究[J]. 地质学报, 1997, 71 (1):45-53.
	HUANG Sijing. A study on carbon and strontium isotopes of Late Paleozoic carbonate rocks in the Upper Yangtze platform[J]. Acta Geologica Sinica, 1997, 71 (1):45-53.
[32]	林耀庭, 熊淑君, 宋鹤彬. 氢氧同位素习性及其在四川盆地卤水成因分类的研究[J]. 四川地质学报, 2001, 21 (3):153-158.
	LIN Yaoting, XIONG Shujun, SONG Hebin. Hydrogen and oxygen isotope composition and their significance of genetic classification of brines in Sichuan basin[J]. Acta Geologica Sichuan, 2001, 21 (3):153-158.