Dynamic sealing evolution and hydrocarbon accumulation of evaporite cap rocks:an example from Kuqa foreland basin thrust belt
Zhuo Qingong1, Zhao Mengjun1, Li Yong2, Wang Yuan2
1. PetroChina Research Institute of Petroleum Exploration and Development, Beijing 100083, China;
2. Research Institute of Petroleum Exploration and Development, PetroChina Tarim Oilfield Company, Xinjiang Korla 841000, China
Due to the effects of mechanical factors and regional tectonic stress, evaporites can form faults and fractures, leading to large-scale oil and gas migration through the cap rocks. The results of triaxial stress-strain experiment with heating and pressurizing show that evaporites feature embrittlement with shallow depth and low temperature, ductile deformation with deep depth and high temperature, and failure deformation with strong extrusion. The crucial formation temperature for brittle-ductile transition of evaporites is approximately 100℃. Taking into consideration the paleotemperature parameters during hydrocarbon accumulation, it is determined the crucial burial depth for brittle-ductile transition of evaporites reaches 3 000 m in Kuqa foreland thrust belt. The ductile evaporite cap rocks are hardly broken by flow during compression, and the existing faults are closed or welded due to salt rock flow. The above findings can be supported by strong evidence including field characteristics of salt structures and microscopic characteristics of fluid inclusions contained in evaporites. Therefore, the sealing of evaporite cap rocks is evolutive during the geological history in Kuqa foreland thrust belt and features specific spatial pattern, thereby controlling the process of hydrocarbon accumulation and associated difference in the thrust belt.
Ulisses T M,Carry D K.Development of sediment overpressure and its effective thermal maturation:application to the Gulf of Mexico Basin[J].AAPG Bulletin,1996,80(9):1367-1396.
Zhang Chaojun,Tian Zaiyi.The Tertiary salt structure and hydrocarbon in Kuqa depression,Tarim Basin[J].Acta Petrolei Sinica,1998,19(1):6-10.
[3]
Grunau H R.Worldwide review of seals for major accumulations of natural gas(abs.)[J].AAPG Bulletin,1981,65:933.
[4]
Mclntyre J F.Presence and control of evaporite top seals on occurrence and distribution of hydrocarbon traps:main fairway,central overthrust belt.Wyoming and Utah(abs.)[J].AAPG Bulletin,1988,72(1):221.
[5]
Rangel H D,Guimaraes P T,Spadini A R.Barracuda and Roncador giant oil fields,deep-water Campos Basin,Brazil[J].AAPG Memoir,2003,78:123-137.
Lin Wen,Zhou Jinying.The new progress of global deepwater oil and gas exploration and deepwater exploration in the north of South China Sea[J].Geophysical Prospecting for Petroleum,2009,48(6):601-605.
[7]
Schreiber B C.Evaporites and hydrocarbons[M].New York:Columbia University Press,1988.
Zhao Zhenyu,Zhou Yaoqi,Ma Xiaoming,et al.The impact of saline deposit upon the hydrocarbon accumulation in petroliferous basin[J].Oil & Gas Geology,2007,28(2):299-308.
Zhuo Qingong,Li Yong,Song Yan,et al.Evolution of Paleogene saline deposits and effectiveness of traps in Kelasu tectonic zone,Kuqa depression,Tarim Basin[J].Petroleum Geology & Experiment,2013,35(1):42-47.
[11]
Schleder Z,Urai J L,Nollet S,et al.Solution-precipitation creep and fluid flow in halite:a case study of Zechstein (Z1)rocksalt from Neuhof salt mine (Germany)[J].International Journal of Earth Science,2007,97(5):1045-1056.
[12]
Neal J T,Magorian T R,Thoms R L,et al.Anomalous zones in GulfCoast salt domes with special reference to Big Hill,TX,and Weeks Island,LA[R].Sandia National Laboratories Report,Albuquerque,New Mexico and Livermore,California.Unlimited Release Report,1993:92-2283.
[13]
Zhuo Qingong,Meng Fanwei,Song Yan,et al.Hydrocarbon migration through salt:evidence from Kelasu tectonic zone of Kuqa foreland basin in China[J].Carbonates and Evaporites,2014,29(3): 291-297.
[14]
Evans J P,Chester F M.Fluid-rock interaction in faults of the San Andreas system:inferences from San Gabriel fault rock geochemistry and microstructures[J].Journal of Geophysical Research,1995,100(B7):13007-13020.
[15]
Faulkner D R,Jackson C A L,Lunn R J,et al.A review of recent developments concerning the structure,mechanics and fluid flow properties of fault zones[J].Journal of Structural Geology,2010,32(11):1557-1575.
Gao Xiaoping,Yang Chunhe,Wu Wen,et al.Experimental studies on temperature effect of mechanical properties of rock salt[J].Rock and Soil Mechanics,2005,26(11):1775-1778.
He Guangyu,Lu Huafu,Wang Liangshu,et al.Characteristics of source rocks and hydrocarbon generation in the Kuqa Basin,northwest China[J].Journal of China Coal Society,2002,27(6):570-574.
Zhao Mengjun,Zhang Baomin.Source rocks for a giant gas-accumulating area in the Kuqa forleland depression[J].Chinese Journal of Geology,2002,37(Z1):35-44.
Wang Xin,Jia Chengzao,Yang Shufeng,et al.The time of deformation on the Kuqa fold-and-thrust belt in the southern Tianshan-based on the Kuqa river area[J].Chinese Journal of Geology,2002,76(1):55-63.
Wu Guanghui,Luo Chunshu,Hu Taiping,et al.Fold-related faulting:an example from the Cenozoic salt-overlying beds in the Kuqa depression[J].Chinese Journal of Geology,2007,42(3):496-505.
Jia Chengzao,Song Yan,Wei Guoqi,et al.Geological features and petroleum accumulation in the foreland basins in central and western China[J].Earth Science Frontiers,2005,12(3):3-13.
Zhuo Qingong,Zhao Mengjun,Xie Huiwen,et al.Relationship between reservoir bitumen and hydrocarbon migration in Dabei region,Kuqa foreland basin[J].Petroleum Geology & Experiment,2011,33(2):193-196.
Zhao Mengjun,Song Yan,Qin Shengfei,et al.The multi-stage formation of oil-gas pools and late-stage accumulation of gas in the foreland basins in central and western China[J].Earth Science Frontiers,2005,12(4):525-533.
Li Zhensheng,Liu Deliang.Fault systems in Kuqa area,northern Tarim and its control to oil-gas accumulation[J].Chinese Journal of Geology,2009,44(1):26-34.
Wang Feiyu,Du Zhili,Li Qian,et al.Organic maturity and hydrocarbon generation history of the Mesozoic oil-prone source rocks in Kuqa depression,Tarim Basin[J].Geochimica,2005,34(2):136-144.
Wang Liangshu,Li Cheng,Liu Shaowen,et al.Terrestrial heat flow distribution in Kuqa foreland basin,Tarim,NW China[J].Petroleum Exploration and Development,2005,32(4):79-84.
[28]
Davison I.Faulting and fluid flow through salt[J].Journal of the Geological Society,2009,166(2):205-216.
Liang Weiguo,Zhang Chuanda,Gao Hongbo,et al.Experimental study of mechanical properties of gypsum saturated in brine[J].Chinese Journal of Rock Mechanics and Engineering,2010,29(6):1156-1163.
Wu Fangfang,Zhu Guangyou,Zhang Shuichang,et al.Types of hydrocarbon migration pathways and its controlling effects on hydrocarbon distribution in Tarim Basin[J].Acta Petrolei Sinica,2009,30(3):333-341.
Wang Xin,Tang Pengcheng,Xie Huiwen,et al.Cenozoic salt structures and evolution in the western Kuqa depression,Tarim Basin,China[J]. Geotectonica et Metallogenia,2009,33(1):57-65.
Qi Jiafu,Lei Ganglin,Li Minggang,et al.Analysis of structure model and formation mechanism of Kelasu structure zone,Kuqa, Depression[J].Geotectonica et Metallogenia,2009,33(1):49-56.
Neng Yuan,Qi Jiafu,Xie Huiwen,et al.Structural characteristics of northern margin of Kuqa depression,Tarim Basin[J].Geological Bulletin of China,2012,31(9):1510-1519.