Source Kitchen and Natural Gas Accumulation in Kuqa Depression, Tarim Basin

Abstract

Abstract: Based on the simulated test data, the chemical kinetics parameters of natural gas generation rate and carbon isotope from the typical source rocks in Kuqa depression of Tarim basin are established. In view of the geologic data and the present- and paleo- geothermal data from exploration wells and artificial wells, the changes of maturity and gas generation rate with time for each well are analyzed with BasinMod software. And the hydrocarbon generating history and source kitchen evolution of Jurassic-Triassic source rocks are recognized. It is suggested that the late and fast burial and mature of source rocks in Kuqa depression since the Neogene, in particular, the rapid deposition of Kuqa formation since the Pliocene (5×10⁶ a BP) lead to sudden increase of the maturity of source rocks, entering into dry gas stage with extremely high gas generation rate. This is a significant reason for formation of highly active natural gas pool in this depression. As shown by the chemical and stable carbon isotope compositions of the discovered gases, the formation of the giant gas pool in Kela-2, Yaha underwent very different geological processes due to the differences in their gas source kitchens. Gases in Yaha condensate gas field in the frontal uplift zone appear to represent gases generated within early to middle oil window with relatively isotopic light gas, whereas the isotopic heavy gases in Kela-2 gas field in Kelasu-Yigikelike Yi structural belt are most likely high maturity gases (R_o:1.0%~2.5%) generated since 5×10⁶ a BP.

Key words: Tarim basin, Kuqa depression, source kitchen, chemical kinetics, hydrocarbon generating history, gas generation and accumulation

CLC Number:

TE112.113

WANG Fei-yu, DU Zhi-li, ZHANG Shui-chang, ZHANG Bao-min, CHEN Jian-ping, Bernhard Cramer. Source Kitchen and Natural Gas Accumulation in Kuqa Depression, Tarim Basin[J]. Xinjiang Petroleum Geology, 2009, 30(4): 431-439.

References

[1] 贾承造,何登发. 前陆冲断带油气勘探[M]. 北京:石油工业出版社,2000.
[2] 贾承造,胡云杨. 塔里木盆地库车坳陷大气田勘探[M].北京:石油工业出版社,2001.
[3] Thomas B M,Moller-Pedersen P,Whitaker M F,et al.Organic facies and hydrocarbon distributions in the Nor-wegian North Sea [A]. In:Petroleum Geochemistry in Ex-ploration of the Norwegian Shelf,Graham and Trotman[C].London,1985:3-26.
[4] Demaison G J.Genetic classification of petroleum system[J].AAPG Bull.,1994,75:1 626-1 643.
[5] 王飞宇,张水昌,张宝民,等. 塔里木盆地库车坳陷中生界源岩有机成熟度[J].新疆石油地质,1999,15(4):301-306.
[6] 梁狄刚,陈建平,王飞宇,等. 塔里木盆地库车坳陷陆相油气的生成[M]. 北京:石油工业出版社,2004.
[7] 王飞宇,杜治利,李谦,等. 塔里木盆地库车坳陷中生界油源岩有机成熟度和生烃历史[J]. 地球化学,2005,34(2):136-146.
[8] 杜治利,王飞宇,张水昌,等. 库车坳陷中生界气源灶生气强度演化特征[J]. 地球化学,2006,35(4):333-345.
[9] 汤良杰,贾承造. 库车前陆褶皱带盆地构造样式[J]. 中国科学,2003,33(1):38-46.
[10] Brewer J.Thermal effects of thrust faulting[J]. Earth and Planetary Science Letters ,1981,56:233-244.
[11] Edman J D,Surdam R C.Influence of overthrusting on mat-uration of hydrocarbon in Phosphoria formation,Wyoming-Idaho-Utah overthrust belt[J]. AAPG Bull.,1984,8(11):1 803-1 817.
[12] Deming D,Chapman D S.Thermal histories and hydrocar-bon generation: example from Utah-Wyoming thrust belt[J]. AAPG Bull.,1989,73(12):1 455-1 471.
[13] Platte River Association,Inc. BasinMod 1-D for Windows.Denver,CO,USA,2001.
[14] 戴金星. 中国天然气地质学(卷一)[M]. 北京:石油工业出版社,1992.
[15] 戴金星. 中国大气田及气源[M]. 北京:科学出版社,2003.
[16] Cramer B,Krooss B M,Littke R.Modelling isotope frac-tionation during primary cracking of natural gas: a reaction kinetic approach[J]. Chemical Geology,1998,149:235-250.
[17] Cramer B,Faber E,Gerling P,et al.Reaction kinetics of stable carbon isotopes in natural gas: Insights from dry,open system pyrolysis experiments[J]. Energy & Fuels,2001,15:517-532.
[18] Zhao W Z,Zhang S C,Wang F Y,et al.Gas systems in the Kuche depression of the Tarim basin: source rock distributi-ons, generation kinetics and gas accumulation history[J].Org. Geochem.,2005,36(12): 1 583-1 601.
[19] 赵孟军,卢双舫. 克拉2 气田地球化学和成藏过程[J].科学通报,2002, (增刊):111-115.