Genesis of lacustrine carbonate breccia and its significance for hydrocarbon exploration in Yingxi region, Qaidam Basin, NW China
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摘要
To examine the reservoir type and distribution regularity of high-and stable-yield lacustrine carbonates in the upper Member of Paleogene Xiaganchaigou Formation of Yingxi region and to determine the high-efficiency hydrocarbon exploration direction, the origin and significance of carbonate breccia in this area were investigated based on comprehensive analysis of a large number of well cores, thin sections, rock and mineral testing and log-seismic data. The study reveals that the carbonate breccia has three origins:(1) Sedimentary breccia, formed by the event-related collapse, fragmentation and re-deposition of the early weakly consolidated carbonate rock in the steep slope of underwater paleohighs due to short-term high-energy water body reformation and other geological processes.(2) Diagenetic breccia, with breccia-like structure, formed by deformation or breaking of host rock due to growth of idiomorphic and coarse crystalline gypsum-salt minerals in the weakly consolidated argillaceous carbonate rock of the penecontemporaneous period.(3) Tectonic breccia, can be further divided into fault breccia and interlayer slip breccia according to their occurrence characteristics, both of which are closely related to activity of the Shizigou thrust Fault. With a large number of partially filled pores, vugs and fractures between breccia, the two types of tectonic breccia are high-and stable-yield reservoirs in deep Yingxi region, and may occur extensively under gypsum-salt detachment layers of adjacent areas, so they are the exploration targets in the next step. Sedimentary breccia and diagenetic breccia are of great significance in searching for large-scale carbonate reservoirs.
To examine the reservoir type and distribution regularity of high-and stable-yield lacustrine carbonates in the upper Member of Paleogene Xiaganchaigou Formation of Yingxi region and to determine the high-efficiency hydrocarbon exploration direction, the origin and significance of carbonate breccia in this area were investigated based on comprehensive analysis of a large number of well cores, thin sections, rock and mineral testing and log-seismic data. The study reveals that the carbonate breccia has three origins:(1) Sedimentary breccia, formed by the event-related collapse, fragmentation and re-deposition of the early weakly consolidated carbonate rock in the steep slope of underwater paleohighs due to short-term high-energy water body reformation and other geological processes.(2) Diagenetic breccia, with breccia-like structure, formed by deformation or breaking of host rock due to growth of idiomorphic and coarse crystalline gypsum-salt minerals in the weakly consolidated argillaceous carbonate rock of the penecontemporaneous period.(3) Tectonic breccia, can be further divided into fault breccia and interlayer slip breccia according to their occurrence characteristics, both of which are closely related to activity of the Shizigou thrust Fault. With a large number of partially filled pores, vugs and fractures between breccia, the two types of tectonic breccia are high-and stable-yield reservoirs in deep Yingxi region, and may occur extensively under gypsum-salt detachment layers of adjacent areas, so they are the exploration targets in the next step. Sedimentary breccia and diagenetic breccia are of great significance in searching for large-scale carbonate reservoirs.
To examine the reservoir type and distribution regularity of high-and stable-yield lacustrine carbonates in the upper Member of Paleogene Xiaganchaigou Formation of Yingxi region and to determine the high-efficiency hydrocarbon exploration direction, the origin and significance of carbonate breccia in this area were investigated based on comprehensive analysis of a large number of well cores, thin sections, rock and mineral testing and log-seismic data. The study reveals that the carbonate breccia has three origins:(1) Sedimentary breccia, formed by the event-related collapse, fragmentation and re-deposition of the early weakly consolidated carbonate rock in the steep slope of underwater paleohighs due to short-term high-energy water body reformation and other geological processes.(2) Diagenetic breccia, with breccia-like structure, formed by deformation or breaking of host rock due to growth of idiomorphic and coarse crystalline gypsum-salt minerals in the weakly consolidated argillaceous carbonate rock of the penecontemporaneous period.(3) Tectonic breccia, can be further divided into fault breccia and interlayer slip breccia according to their occurrence characteristics, both of which are closely related to activity of the Shizigou thrust Fault. With a large number of partially filled pores, vugs and fractures between breccia, the two types of tectonic breccia are high-and stable-yield reservoirs in deep Yingxi region, and may occur extensively under gypsum-salt detachment layers of adjacent areas, so they are the exploration targets in the next step. Sedimentary breccia and diagenetic breccia are of great significance in searching for large-scale carbonate reservoirs.
引文
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[17]ZHAO Wenzhi,SHEN Anjiang,HU Suyun,et al.Geological conditions and distributional features of large-scale carbonate reservoirs onshore China.Petroleum Exploration and Development,2012,39(1):1-12.
[18]LIU Wei,MENG Qingyang,ZHANG Guangya,et al.Geologic characteristics of oil and gas reservoirs in old lower Paleozoic and Sinian Carbonate rocks.Marine Origin Petroleum Geology,2010,15(1):15-20.
[19]LI Yuankui,TIE Zhanyuan,WANG Bo,et al.N1-E1+2 fractured reservoir evaluation and control factors of petroleum accumulation in Shizigou Structure,Qaidam Basin.Qinghai Petroleum,2010,28(2):1-6.
[20]LI Hai,TANG Dazhen,XU Hao,et al.Analysis of hydrocarbon accumulation period in Paleogene reservoirs,Shizigou oilfield of Qaidam Basin.Petroleum Geology&Recovery Efficiency,2013,20(3):30-32.
[21]CHEN Dengqian,SHEN Xiaoshuang,CUI Jun,et al.Reservoir characteristics and controlling factors of deep diamictite in Yingxi area,Qaidam Basin.Lithologic Reservoirs,2015,27(5):211-217.
[22]HUANG Chenggang,GUAN Xin,NI Xianglong,et al.The characteristics and major factors controlling on the E32 dolomite reservoirs in saline lacustrine basin in the Yingxi area of Qaidam Basin.Natural Gas Geoscience,2017,28(2):219-231.
[23]LIU Zhanguo,ZHU Chao,LI Senming,et al.Geological features and exploration fields of tight oil in the Cenozoic of western Qaidam Basin,NW China.Petroleum Exploration and Development,2017,44(2):196-204.
[24]DENG Hongwen,QIAN Kai.Sedimentary geochemistry and environmental analysis.Lanzhou:Gansu Science Press,1993.
[25]CHEN Nenggui,WANG Yanqing,XU Feng,et al.Palaeo-salinity and its sedimentary response to the Cenozoic salt water lacustrine deposition in Qaidam Basin.Journal of Palaeogeography,2015,17(3):371-380.
[26]XIA Zhiyuan,LIU Zhanguo,LI Senming,et al.Origin and developing model of rock salt:A case study of Lower Ganchaigou Formation of Paleogene in the west of Yingxiong ridge,Qaidam Basin.Acta Petrolei Sinica,2017,38(1):55-66.
[2]RYU I C,DOH S J,CHOI S G.Carbonate breccias in the lower-middle Ordovician Maggol limestone(Taebacksan Basin,South Korea):Implications for regional tectonism.Facies,2002,46(1):35-56.
[3]FRDRIC B,MICHEL S,ALEXIS M.Coarse carbonate breccias as a result of water-wave cyclic loading(uppermost Jurassic-South-East Basin,France).Sedimentology,2001,48(4):767-789.
[4]SEGURET M,MOUSSINE-POUCHKINE A,GABAGLIA GR,et al.Storm deposits and storm-generated coarse carbonate breccias on a pelagic outer shelf(South-East Basin,France).Sedimentology,2001,48(2):231-254.
[5]PAYROS A,PUJALTE V,ORUE-ETXEBARRIA X.The South Pyrenean Eocene carbonate megabreccias revisited:New interpretation based on evidence from the Pamplona Basin.Sedimentary Geology,1999,125(3):165-194.
[6]HONG Qingyu.The carbonate gravity flow sediments in the juncture of Yunnan,Guizhou and Guangxi.Journal of Southwest Petroleum Institute,1982,4(1):1-11.
[7]MEI Zhichao,CHEN Jingwei,LU Huanyong,et al.Deep water carbonate debris flow in the middle Ordovician Pingliang formation of Fuping,Shaanxi.Oil and Gas Geology,1982,3(1):49-56.
[8]Carbonate Rock Research Office.Deep water carbonate brecclas in the Nanpan river area during the Permian and Triassic periods.Journal of Southwest Petroleum Institute,1982,4(3):1-26.
[9]LUO Zuyu.Preliminary study on Triassic and late Paleoxoic reef facies in Yunnan-Guizhou-Guangxi region and their Petroleum prospect.Experimental Petroleum Geology,1983,5(1):18-28.
[10]DU Yelong,LI Shuangying,JIA Zhihai,et al.Re-discussion on the origin of the rudstone in Middle Permian Qixia Formation along Lower Yangtze River of Anhui Province.Geological Review,2012,58(3):426-433.
[11]BLOUNT D N,MOORE C H.Depositional and non-depositional carbonate breccias,Chiantla Quadrangle,Guatemala.Geological Society of America Bulletin,1969,80(3):429-442.
[12]MORROW D W.Descriptive field classification of sedimentary and diagenetic breccia fabrics in carbonate rocks.Bulletin of Canadian Petroleum Geology,1982,30(3):227-229.
[13]LIU Hong,MA Teng,TAN Xiucheng,et al.Origin of structurally controlled hydrothermal dolomite in epigenetic karst system during shallow burial:An example from Middle Permian Maokou Formation,central Sichuan Basin,SW China.Petroleum Exploration and Development,2016,43(6):1000-1012.
[14]LI Wenke,ZHANG Yan,ZHANG Baomin,et al.Origin,characteristics and significance of collapsed-paleocave systems in Sinian to Permian carbonate strata in Central Sichuan Basin,SW China.Petroleum Exploration and Development,2014,41(5):513-522.
[15]WILSHIRE H G,HOWARD K A,OFFIELD T W.Impact breccias in carbonate rocks,Sierra Madera,Texas.Geological Society of America Bulletin,1971,82(4):1009-1017.
[16]TARASEWICZ J P T,WOODCOCK N H,DICKSON J A D.Carbonate dilation breccias:Examples from the damage zone to the Dent Fault,northwest England.Geological Society of America Bulletin,2005,117(5):6722-6723.
[17]ZHAO Wenzhi,SHEN Anjiang,HU Suyun,et al.Geological conditions and distributional features of large-scale carbonate reservoirs onshore China.Petroleum Exploration and Development,2012,39(1):1-12.
[18]LIU Wei,MENG Qingyang,ZHANG Guangya,et al.Geologic characteristics of oil and gas reservoirs in old lower Paleozoic and Sinian Carbonate rocks.Marine Origin Petroleum Geology,2010,15(1):15-20.
[19]LI Yuankui,TIE Zhanyuan,WANG Bo,et al.N1-E1+2 fractured reservoir evaluation and control factors of petroleum accumulation in Shizigou Structure,Qaidam Basin.Qinghai Petroleum,2010,28(2):1-6.
[20]LI Hai,TANG Dazhen,XU Hao,et al.Analysis of hydrocarbon accumulation period in Paleogene reservoirs,Shizigou oilfield of Qaidam Basin.Petroleum Geology&Recovery Efficiency,2013,20(3):30-32.
[21]CHEN Dengqian,SHEN Xiaoshuang,CUI Jun,et al.Reservoir characteristics and controlling factors of deep diamictite in Yingxi area,Qaidam Basin.Lithologic Reservoirs,2015,27(5):211-217.
[22]HUANG Chenggang,GUAN Xin,NI Xianglong,et al.The characteristics and major factors controlling on the E32 dolomite reservoirs in saline lacustrine basin in the Yingxi area of Qaidam Basin.Natural Gas Geoscience,2017,28(2):219-231.
[23]LIU Zhanguo,ZHU Chao,LI Senming,et al.Geological features and exploration fields of tight oil in the Cenozoic of western Qaidam Basin,NW China.Petroleum Exploration and Development,2017,44(2):196-204.
[24]DENG Hongwen,QIAN Kai.Sedimentary geochemistry and environmental analysis.Lanzhou:Gansu Science Press,1993.
[25]CHEN Nenggui,WANG Yanqing,XU Feng,et al.Palaeo-salinity and its sedimentary response to the Cenozoic salt water lacustrine deposition in Qaidam Basin.Journal of Palaeogeography,2015,17(3):371-380.
[26]XIA Zhiyuan,LIU Zhanguo,LI Senming,et al.Origin and developing model of rock salt:A case study of Lower Ganchaigou Formation of Paleogene in the west of Yingxiong ridge,Qaidam Basin.Acta Petrolei Sinica,2017,38(1):55-66.