Neogene natural gas genesis and hydrocarbon differential enrichment mechanism in the basin marginal sag of Bohai Bay Basin: a case study of the eastern subsag of Huanghekou sag
Yang Haifeng, Wang Deying, Gao Yanfei, Wang Jun, Li Zhengyu, Qian Geng
Tianjin Branch, CNOOC China Limited, Tianjin 300459, China
It was previously considered that the basin marginal sag had shallow buried depth, small area and limited hydrocarbon generation capacity, thus attracting little attention. Now the basin marginal sag has become the key hotspot of oil and gas exploration in the Bohai Bay Basin, and the hydrocarbon accumulation mechanisms and enrichment laws needs to be further explored. Based on the geochemical data, the Neogene hydrocarbon accumulation mechanism and distribution laws of the eastern subsag in Huanghekou sag were systematically studied. The results show that the Neogene crude oil and natural gas of the eastern subsag in Huanghekou sag have different sources and geneses; the crude oil originated from source rocks in the Paleogene Members 3 and 4 of Shahejie Formation, while the natural gas was the secondary biogas resulting from crude oil degradation in Neogene reservoirs. The formation of crude oil was earlier than that of natural gas, while gas reservoir is shallower than that of oil reservoir. However, the specific distribution of gas and oil reservoirs was controlled by the sealing capacities of three sets of regional caps in the mid-upper Neogene Guantao Formation, the mid-lower Minghuazhen Formation and the upper bottom of Minghuazhen Formation, showing an overall distribution law of "rich oil in the south, rich gas in the north; rich oil in the west, rich gas in the east; rich oil in the lower part, rich gas in the upper part".
杨海风, 王德英, 高雁飞, 王军, 李正宇, 钱赓. 渤海湾盆地盆缘洼陷新近系天然气成因与油气差异富集机理——以黄河口凹陷东洼为例[J]. 石油学报, 2019, 40(5): 509-518.
Yang Haifeng, Wang Deying, Gao Yanfei, Wang Jun, Li Zhengyu, Qian Geng. Neogene natural gas genesis and hydrocarbon differential enrichment mechanism in the basin marginal sag of Bohai Bay Basin: a case study of the eastern subsag of Huanghekou sag[J]. Acta Petrolei Sinica, 2019, 40(5): 509-518.
ZHANG Shulin,FEI Qi,YE Jiaren.Types and structural characteristics of brink sags in faulted basin[J].Petroleum Geology and Experiment,2007,29(1):47-51.
DENG Yunhua,XUE Yong'an,YU Shui,et al.Shallow hydrocarbon migration and accumulation theory and discovery of giant oilfield group in Bohai Sea[J].Acta Petrolei Sinica,2017,38(1):1-8.
XUE Yong'an.The "catchment ridge" model of hydrocarbon migration in Bohai Sea and its control on Neogene hydrocarbon accumulation[J].Acta Petrolei Sinica,2018,39(9):963-970.
XUE Yong'an,YANG Haifeng,XU Changgui.Differential reservoir-controlling effect and hydrocarbon enrichment of slope zone in Huanghekou sag,Bohai Bay Basin[J].China Petroleum Exploration,2016,21(4):65-74.
ZHU Guangyou,JIN Qiang,ZHOU Jianlin,et al.Physical properties and genesis of oil in Shengtuo oilfield in Jiyang depression[J].Oil & Gas Geology,2004,25(1):9-13.
LIU Hua,JIANG Youlu,CAI Dongmei,et al.Physical properties and influence factors of crude oil from Paleogene in Dongying sag[J].Petroleum Geology and Recovery Efficiency,2006,13(3):8-11.
HAO Bin,ZHAO Wenzhi,HU Suyun,et al.Bitumen genesis and hydrocarbon accumulation history of the Cambrian Longwangmiao Formation in Central Sichuan Basin[J].Acta Petrolei Sinica,2017,38(8):863-875.
WANG Jun,ZHOU Xinhuai,YANG Bo,et al.Oil-source correlation of severely biodegraded oil of PL 9-1 oilfield in Bohai Sea[J].China Offshore Oil and Gas,2017,29(6):32-42.
[9]
PETERS K E,MOLDOWAN J M.Effects of source,thermal maturity,and biodegradation on the distribution and isomerization of homohopanes in petroleum[J].Organic Geochemistry,1991,17(1):47-61.
[10]
PETERS K E,WALTERS C C,MOLDOWAN J M.The biomarker guide:biomarkers and isotopes in petroleum exploration and earth history[M].2nd ed.Cambridge:Cambridge University Press,2005:569.
PANG Xiongqi,GUO Yonghua,JIANG Fujie,et al.High-quality source rocks and their distribution prediction in the Bohai Sea water[J].Oil & Gas Geology,2009,30(4):393-397.
[12]
朱伟林,米立军,龚再升.渤海海域油气成藏与勘探[M].北京:科学出版社,2009:11-226.
ZHU Weilin,MI Lijun,GONG Zaisheng.Hydrocarbon accumulation and exploration of Bohai Sea[M].Beijing:Science Press,2009:11-226.
[13]
HAO Fang,ZHOU Xinhuai,ZHU Yangming,et al.Charging of the Neogene Penglai 19-3 field,Bohai Bay Basin,China:oil accumulation in a young trap in an active fault zone[J].AAPG Bulletin,2009,93(2):155-179.
XIE Yuhong,ZHANG Gongcheng,SHEN Pu,et al.Formation conditions and exploration direction of large gas field in Bozhong sag of Bohai Bay Basin[J].Acta Petrolei Sinica,2018,39(11):1199-1210.
[15]
FU Jiamo,SHENG Guoying,XU Jiayou,et al.Application of biological markers in the assessment of paleoenvironments of Chinese non-marine sediments[J]. Organic Geochemistry,1990,16(4/6):769-779.
LIU Wenhui,CHEN Mengjin,GUAN Ping,et al.Ternary geochemical-tracing system and practice in natural gas generation and accumulation[M].Beijing:Science Press,2009:119-126.
[17]
宋岩,徐永昌.天然气成因类型及其鉴别[J].石油勘探与开发,2005,32(4):24-29.
SONG Yan,XU Yongchang.Origin and identification of natural gases[J].Petroleum Exploration and Development,2005,32(4):24-29.
[18]
戴金星.各类烷烃气的鉴别[J].中国科学:B辑,1992(2):187-193.
DAI Jinxing.Identification and distinction of various alkane gases[J].Science in China:Series B,1992(2):187-193.
[19]
刘文汇,徐永昌.天然气成因类型及判别标志[J].沉积学报,1996,14(1):110-116.
LIU Wenhui,XU Yongchang.Genetic indicators for natural gases[J].Acta Sedimentologica Sinica,1996,14(1):110-116.
DAI Jinxing,CHEN Ying.Characteristics of carbon isotopes of alkane components and identification marks of biogenic gases in China[J].Science in China:Series B,1994,37(2):231-241.
WANG Quan,CAO Yijun,DIAO Fan,et al.The distribution and origin analysis of natural gas in Langgu sag,Bohai Bay Basin[J].Natural Gas Geoscience,2017,28(9):1363-1374.
WANG Zhengjun,ZHU Guangyou,WANG Zhengguo,et al.Characteristics of oil-biodegradation gas and their discriminant index system[J].Natural Gas Industry,2008,28(11):29-33.
[23]
HEAD I M,JONES D M,LARTER S R.Biological activity in the deep subsurface and the origin of heavy oil[J].Nature,2003,426(6964):344-352.
[24]
WILHELMS A,LARTER S R,HEAD I,et al.Biodegradation of oil in uplifted basins prevented by deep-burial sterilization[J].Nature,2001,411(6841):1034-1037.
[25]
LARTER S R,WILHELM A,HEAD I,et al.The controls on the composition of biodegraded oils in the deep subsurface-part 1:biodegradation rates in petroleum reservoir[J].Organic Geochemistry,2003,34(4):601-613.
[26]
李明宅,张洪年.生物气成藏规律研究[J].天然气工业,1997,17(2):6-10.
LI Mingzhai,ZHANG Hongnian.Research on the formation of biogas reservoir[J].Natural Gas Industry,1997,17(2):6-10.
[27]
KRUMHOLZ L R.Microbial communities in the deep subsurface[J].Hydrogeology Journal,2000,8(1):4-10.
YANG Haifeng,LIU Guangdi,LEI Dewen,et al.Differences between oil and gas accumulations in Zhongguai,5th & 8th districts of Karamay oil field,northwestern margin of Junggar Basin[J].Geological Journal of China Universities,2008,14(2):262-268.
CAO Qian,JIN Qiang,CHENG Fuqi.Approach to sealing ability of biological gas cap rock of Quaternary in eastern Qaidam Basin[J].Xinjiang Petroleum Geology,2012,33(5):623-626.
LV Yanfang,ZHANG Shaochen,WANG Yaming.Research of quantitative relations between sealing ability and thickness of cap rock[J].Acta Petrolei Sinica,2000,21(2):27-30.
WU Zhiping.Structural evolution of Tan-Lu fault zone in south area of Bohai Sea and its control on petroleum migration and accumulation[R].Tianjin:Tianjin Branch of CNOOC China Limited,2015.
CHEN Jianyu,CAO Shuchun,CAO Zhongxiang,et al.Dynamics features of gas reservoir forming with shallow-middle depth in the east of China:taking gas reservoirs with shallow-middle depth of Jiyang depression as an example[J].Petroleum Geology and Recovery Efficiency,2001,8(1):13-17.
HUANG Lei,ZHOU Xinhuai,LIU Chiyang,et al.The important turning points during evolution of cenozoic basin offshore the Bohai Sea:evidence and regional dynamics analysis[J].Science China Earth Sciences,2012,55(3):476-487.