库车坳陷东秋里塔格构造带隐伏构造定量化计算
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摘要
库车坳陷膏盐层下伏是油气富集区,由于盐层遮蔽作用,盐下地震反射信息模糊,构造解释存在争议。依据临界楔理论测量克拉苏、迪那构造带盐下逆冲构造楔顶面坡度角α和底部滑脱层倾角β,线性拟合盐下构造楔回归直线,求解岩性强度和底部滑脱断层摩擦强度。东秋里塔格构造带与克拉苏、迪那构造带相邻,构造特征和变形机制一致,岩性强度和底部滑脱层强度参数相近。东秋里塔格构造带盐下逆冲构造楔顶面坡度角α为6°,底部滑脱面倾角β为7°,推断东秋里塔格背斜盐下发育低缓逆冲断层,逆冲断层沿中生界底部滑移。依据沉积楔构造缩短量计算方法,迪那构造带中生界缩短6.5 km,迪那背斜吸收全部缩短量,东秋里塔格构造带中生界缩短9 km,东秋里塔格背斜吸收6 km,剩余3 km需要断层吸收,预测东秋里塔格背斜下伏发育小规模逆冲断层。
The hydrocarbon enrichment zone is underlying the gypsum-salt bed of Kuqa depression. Due to the sheltering effect of salt bed,the under-salt seismic reflection information is fuzzy,and a controversy exists on structural interpretation. According to critical wedge theory,the slope angle α of top surface and dip angle β of basal detachment layer in Kelasu and Dina structural belt uner-salt thrust structure wedges were measured,and the linear fitting to the regression straight line of under-salt structure wedge was carried out to solve the rock strength and frictional strength of basal detachment fault. The Eastern Qiulitage structural belt is neighbored with Kelasu and Dina structural belt,presenting consistent structural characteristics and deformation mechanism as well as nearly the same rock strength and strength parameter of bottom detachment layer. The slope angle of top surface in the Eastern Qiulitage structural belt under-salt thrust structure wedge is α = 6°,and the dip angle of basal detachment layer is β = 7°. It is deduced that low gentle thrust fault was developed in Eastern Qiulitage structural belt under-salt layers,and thrust fault slipped along the bottom of Mesozoic formation. According to the calculation method for the shortening amount of sedimentary wedge structure,Dina structural belt Mesozoic strata were shortened by 6. 5 km and completely absorbed by the Dina anticline. The Mesozoic Eastern Qiulitage structural belt was shortened by 9 km,of which 6 km was absorbed by the Eastern Qiulitage anticline,and 3 km was absorbed by faults. It is predicted that there are small thrust faults underlying the Eastern Qiulitage anticline.
The hydrocarbon enrichment zone is underlying the gypsum-salt bed of Kuqa depression. Due to the sheltering effect of salt bed,the under-salt seismic reflection information is fuzzy,and a controversy exists on structural interpretation. According to critical wedge theory,the slope angle α of top surface and dip angle β of basal detachment layer in Kelasu and Dina structural belt uner-salt thrust structure wedges were measured,and the linear fitting to the regression straight line of under-salt structure wedge was carried out to solve the rock strength and frictional strength of basal detachment fault. The Eastern Qiulitage structural belt is neighbored with Kelasu and Dina structural belt,presenting consistent structural characteristics and deformation mechanism as well as nearly the same rock strength and strength parameter of bottom detachment layer. The slope angle of top surface in the Eastern Qiulitage structural belt under-salt thrust structure wedge is α = 6°,and the dip angle of basal detachment layer is β = 7°. It is deduced that low gentle thrust fault was developed in Eastern Qiulitage structural belt under-salt layers,and thrust fault slipped along the bottom of Mesozoic formation. According to the calculation method for the shortening amount of sedimentary wedge structure,Dina structural belt Mesozoic strata were shortened by 6. 5 km and completely absorbed by the Dina anticline. The Mesozoic Eastern Qiulitage structural belt was shortened by 9 km,of which 6 km was absorbed by the Eastern Qiulitage anticline,and 3 km was absorbed by faults. It is predicted that there are small thrust faults underlying the Eastern Qiulitage anticline.
引文
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[16]王招明.塔里木盆地库车坳陷克拉苏盐下深层大气田形成机制与富集规律[J].天然气地球科学,2014,25(2):153-166.Wang Zhaoming.Formation mechanism and enrichment regularities of Kelasu subsalt deep large gas field in Kuqa depression,Tarim Basin[J].Natural Gas Geoscience,2014,25(2):153-166.
[17]谢会文,李勇,漆家福,等.库车坳陷中部构造分层差异变形特征和构造演化[J].现代地质,2012,26(4):682-690.Xie Huiwen,Li Yong,Qi Jiafu,et al.Differential structural deformation and tectonic evolution in the middle part of Kuqa depression,Tarim Basin[J].Geoscience,2012,26(4):682-690.
[18]Bilotti F,Shaw J H.Deep-water Niger Delta fold and thrust belt modeled as a critical-taper wedge:the influence of elevated basal fluid pressure on structural styles[J].AAPG Bulletin,2005,89(11):1475-1491.
[19]Hubbard J,Shaw J H.Uplift of the Longmen Shan and Tibetan plateau,and the 2008 Wenchuan(M=7.9)earthquake[J].Nature,2009,458(7235):194-197.
[20]Yue Lifan,Suppe J,Hung J H.Structural geology of a classic thrust belt earthquake:the 1999 Chi-Chi earthquake Taiwan(Mw=7.6)[J].Journal of Structural Geology,2005,27(11):2058-2083.
[21]Suppe J.Geometry and kinematics of fault-bend folding[J].American Journal of Science,1983,283(7):684-721.
[2]Dahlen F A,Suppe J,Davis D.Mechanics of fold-and-thrust belts and accretionary wedges:cohesive Coulomb theory[J].Journal of Geophysical Research,1984,89(B12):10087-10101.
[3]Dahlen F A.Critical taper model of fold-and-thrust belts and accretionary wedges[J].Annual Review of Earth and Planetary Sciences,1990,18(1):55-99.
[4]Suppe J.Absolute fault and crustal strength from wedge tapers[J].Geology,2007,35(12):1127-1130.
[5]李世琴.南天山库车前陆盆地中—西段挤压盐构造及同构造沉积地层研究[D].杭州:浙江大学,2009.Li Shiqin.Compression salt tectonics and synkinematic strata study in the middle to western Kuqa foreland basin,Southern Tian Shan[D].Hangzhou:Zhejiang University,2009.
[6]唐鹏程.南天山库车坳陷西段新生代盐构造:构造分析和物理模拟[D].杭州:浙江大学,2011.Tang Pengcheng.Cenozoic salt structures in the western Kuqa depression,Southern Tianshan:structural analysis and physical modeling[D].Hangzhou:Zhejiang University,2011.
[7]Li Shiqin,Wang Xin,Suppe J.Compressional salt tectonics and synkinematic strata of the western Kuqa foreland basin,southern Tian Shan,China[J].Basin Research,2012,24(4):475-497.
[8]唐鹏程,饶刚,李世琴,等.库车褶皱—冲断带前缘盐层厚度对滑脱褶皱构造特征及演化的影响[J].地学前缘,2015,22(1):312-327.Tang Pengcheng,Rao Gang,Li Shiqin,et al.The impact of salt layer thickness on the structural characteristics and evolution of detachment folds in the leading edge of Kuqa fold and thrust belt[J].Earth Science Frontiers,2015,22(1):312-327.
[9]唐鹏程,李世琴,雷刚林,等.库车褶皱—冲断带拜城凹陷盐构造特征与成因[J].地球科学:中国地质大学学报,2012,37(1):69-76.Tang Pengcheng,Li Shiqin,Lei Ganglin,et al.Characteristics and formation of salt structures in Baicheng sag,Kuqa fold-and-thrust belt[J].Earth Science:Journal of China University of Geosciences,2012,37(1):69-76.
[10]卓勤功,赵孟军,李勇,等.膏盐岩盖层封闭性动态演化特征与油气成藏——以库车前陆盆地冲断带为例[J].石油学报,2014,35(5):847-856.Zhuo Qingong,Zhao Mengjun,Li Yong,et al.Dynamic sealing evolution and hydrocarbon accumulation of evaporite cap rocks:an example from Kuqa foreland basin thrust belt[J].Acta Petrolei Sinica,2014,35(5):847-856.
[11]赵孟军,鲁雪松,卓勤功,等.库车前陆盆地油气成藏特征与分布规律[J].石油学报,2015,36(4):395-404.Zhao Mengjun,Lu Xuesong,Zhuo Qingong,et al.Characteristics and distribution law of hydrocarbon accumulation in Kuqa foreland basin[J].Acta Petrolei Sinica,2015,36(4):395-404.
[12]卢华复,贾东,陈楚铭,等.库车新生代构造性质和变形时间[J].地学前缘,1999,6(4):215-221.Lu Huafu,Jia Dong,Chen Chuming,et al.Nature and timing of the Kuqa Cenozoic structures[J].Earth Science Frontiers,1999,6(4):215-221.
[13]卢华复,陈楚铭,刘志宏,等.库车再生前陆逆冲带的构造特征与成因[J].石油学报,2000,21(3):18-24.Lu Huafu,Chen Chuming,Liu Zhihong,et al.The structural features and origin of the Kuqa rejuvenation foreland thrust belt[J].Acta Petrolei Sinica,2000,21(3):18-24.
[14]汪新,唐鹏程,谢会文,等.库车坳陷西段新生代盐构造特征及演化[J].大地构造与成矿学,2009,33(1):57-65.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.
[15]汪新,贾承造,杨树锋.南天山库车褶皱冲断带构造几何学和运动学[J].地质科学,2002,37(3):372-384.Wang Xin,Jia Chengzao,Yang Shufeng.Geometry and kinematics of the Kuqa fold-and-thrust belt in the southern Tianshan[J].Chinese Journal of Geology,2002,37(3):372-384.
[16]王招明.塔里木盆地库车坳陷克拉苏盐下深层大气田形成机制与富集规律[J].天然气地球科学,2014,25(2):153-166.Wang Zhaoming.Formation mechanism and enrichment regularities of Kelasu subsalt deep large gas field in Kuqa depression,Tarim Basin[J].Natural Gas Geoscience,2014,25(2):153-166.
[17]谢会文,李勇,漆家福,等.库车坳陷中部构造分层差异变形特征和构造演化[J].现代地质,2012,26(4):682-690.Xie Huiwen,Li Yong,Qi Jiafu,et al.Differential structural deformation and tectonic evolution in the middle part of Kuqa depression,Tarim Basin[J].Geoscience,2012,26(4):682-690.
[18]Bilotti F,Shaw J H.Deep-water Niger Delta fold and thrust belt modeled as a critical-taper wedge:the influence of elevated basal fluid pressure on structural styles[J].AAPG Bulletin,2005,89(11):1475-1491.
[19]Hubbard J,Shaw J H.Uplift of the Longmen Shan and Tibetan plateau,and the 2008 Wenchuan(M=7.9)earthquake[J].Nature,2009,458(7235):194-197.
[20]Yue Lifan,Suppe J,Hung J H.Structural geology of a classic thrust belt earthquake:the 1999 Chi-Chi earthquake Taiwan(Mw=7.6)[J].Journal of Structural Geology,2005,27(11):2058-2083.
[21]Suppe J.Geometry and kinematics of fault-bend folding[J].American Journal of Science,1983,283(7):684-721.