摘要
明确塔里木盆地秋里塔格构造带东部箱形褶皱的变形特征与形成机制,可为该构造带的演化过程恢复及油气勘探提供重要参考。根据地震资料反映出的深部地质结构以及箱形褶皱内部的断层和裂缝特征,分析了秋里塔格构造带东部地表箱形褶皱的力学机制及构造演化过程,并讨论了褶皱内部断层和裂缝的成因以及对油气勘探的启示。结果表明:秋里塔格构造带地表箱形褶皱是在喜马拉雅中期和晚期自北向南的强烈挤压背景下,在盐上构造层发生共轭膝折而形成的构造,经历了库车组沉积前的构造平静期、库车组沉积早中期的褶皱雏形期和库车组沉积晚期—现今的褶皱定型与抬升剥蚀期3个演化阶段。箱形褶皱前翼发育的北倾逆冲断层和网状裂缝体系形成于库车组沉积早中期,受深部高矿化度地层水影响被石膏大量充填,但断层的后期活动可将充填物错开;核部上端发育北倾张性断层及近EW向张性裂缝,下端发育小型背冲构造和近NS向的剪切裂缝,中性面位于褶皱中下部;后翼发育南倾反冲断层和层间滑脱作用形成的近EW向层间剪切裂缝;褶皱核部和后翼受高矿化度地层水波及较小,发育的断层及裂缝均未见明显的矿物充填。膝折带及附近地层的储集和渗流能力较强,具有形成油气藏的潜力,正确地解释出覆盖区的膝折带,有望拓展原有油气藏的规模或发现新的油气勘探领域。秋里塔格构造带深层和浅层断层体系相互连通使深部油气向浅层运移成藏,潜在的勘探领域包括在古近系薄砂层和下白垩统上部形成的构造—岩性油气藏,以及在盐上浅表背斜砂岩段形成的构造油气藏2类。
Understanding deformation and formation mechanism of the box fold on the eastern Qiulitage structural belt could provide an important reference for the reconstruction of evolution and petroleum exploration of the Qiulitage structural belt.Using the deep geological structure reflected by seismic data and characteristics of faults and fractures within the box fold,the mechanical mechanism and tectonic evolution of the box fold on the eastern Qiulitage structural belt were analyzed,and the origin of faults and fractures within the box fold were discussed.Besides,the enlightenment of the box fold to petroleum exploration was also discussed.The results show that the surficial box fold on the Qiulitage structural belt was formed by conjugate kinking which was caused by intense compression from north to south at Middle and Late Himalayan Period in the supra salt structural layer.The box fold has experienced three stages,which are tectonic stabilization stage at the pre-Kuqa Period,fold prototype stage at the Early-Middle Kuqa Period,and fold finalization,uplift and denudation stage.The north trend thrust faults and netlike fractures system within the forelimb was formed at the Early-Middle Kuqa Period,and was cemented by gypsum as the influence of deep formation water with high degree of mineralization,but latter fault activity could cut off the cements.The upper fold core develops north trend tensile faults and~EW strike tensile fractures,while the lower develops small back thrust and~NS strike shearing fractures,and the neutral plane was supposed to be at the middle-lower of the fold.The backlimb develops south trend backthrust faults and~EW strike interbedded shearing fractures by interbedded detachment.The core and backlimb of the fold were weakly affected by formation water with high degree of mineralization,therefore faults and fractures in them have not remarkable cementation.The kinks and nearby formation have high reserve and seepage capacity,and thus have the potential to form petroleum reservoirs.Interpreting kinking bands in the overburden areas correctly would be hopeful to broaden the scale of original petroleum reservoirs or discover new petroleum exploration realms.In the Qiulitage structural belt,the interconnection of deep and shallow fault system leads to deep oil and gas migrating to shallow and accumulating in shallow.The potential exploration fields in shallow including two primary types,i.e.structural-lithologic petroleum reservoir formed in the thin sand layer of Palaeogene and the upper layer of Lower Cretaceous,and structural petroleum reservoir formed in sandstone layers of suprasalt surficial folds.
作者
王珂
张荣虎
曾庆鲁
王俊鹏
WANG Ke;ZHANG Ronghu;ZENG Qinglu;WANG Junpeng(PetroChina Hangzhou Research Institute of Geology,Hangzhou 310023,China;PetroChina Research Institute of Petroleum Exploration and Development,Beijing 100083,China)
出处
《天然气地球科学》
CAS
CSCD
北大核心
2022年第9期1384-1396,共13页
Natural Gas Geoscience
基金
中国石油“十四五”上游领域前瞻性基础性课题(编号:2021DJ0302)
国家重点研发计划(编号:2019YFC0605501)联合资助
关键词
箱形褶皱
断层
裂缝
膝折
构造演化
油气勘探
秋里塔格构造带
Box fold
Faults
Fractures
Kink
Tectonic evolution
Petroleum exploration
Qiulitage structural belt
作者简介
王珂(1987-),男,山东郓城人,高级工程师,博士,主要从事前陆盆地构造地质与储层地质研究.E-mail:wangk_hz@petrochina.com.cn.
