【作者】 余一欣；

【导师】 汤良杰；

【作者基本信息】 中国石油大学 ， 地质资源与地质工程， 2006， 博士

【摘要】 库车坳陷秋里塔格构造带沉积有较厚的古近系和新近系膏盐层,受盐下基底构造、沉积差异负载和构造挤压应力等因素影响,膏盐层发生了明显的塑性流动,影响了该地区的构造变形与演化过程,形成了丰富多样的盐相关构造样式,并对油气运聚成藏过程有重要的控制作用。秋里塔格构造带构造变形特征表现为复杂的盐下层、盐层和盐上层“三位一体”叠加构造变形。纵向上,可分为盐下构造、盐层构造和盐上构造三类,横向上,盐相关构造表现出明显的分段差异变形特征。秋里塔格构造带西段前古近纪基底表现为受先存基底断裂控制的古隆起形态,其雏形开始形成于奥陶纪,在泥盆纪-三叠纪得到进一步发展,定型期则主要为侏罗纪。前古近纪基底古构造对盐相关构造的形成产生了重要的影响作用。通过平衡剖面复原,得出秋里塔格构造带盐相关构造的主要形成期为库车期-第四纪。库车坳陷南北向缩短量为20~35 km,约占整个剖面的20%~35%。库车坳陷挤压构造变形具有“分层缩短、分带缩短”的特点,膏盐层在盐上层和盐下层的差异变形过程中起到了非常重要的滑脱、调节作用。库车坳陷盐构造形成演化序列整体具有从北往南迁移的特点,在前缘秋里塔格构造带则表现为从西往东迁移。在盐构造发育的初期阶段,控制盐体运动与盐构造发育的主要因素是由拜城凹陷巨厚沉积物所导致的沉积差异负载作用,但对目前已发育较成熟的盐构造而言,最主要的影响因素则是挤压应力作用。盐构造物理模拟实验证实,基底断裂、古隆起和构造斜坡的存在影响了盐体的运动方式,导致盐体在古隆起顶部聚集增厚,以及大型北倾滑脱断层和断层传播褶皱的形成。膏盐层在构造变形过程中主要起滑脱层作用及充填背斜核部,很少形成刺穿型盐构造。通过对秋里塔格构造带盐相关构造特征对油气运聚成藏的控制作用的综合分析,建立了该地区可能存在的油气聚集成藏模式,并指出了下一步有利油气勘探方向。更多还原

【Abstract】 The Paleogene Kumugeliemu Formation and Neogene Jidike Formation attain thick halite layers in the Qiulitag structural belt which is located in the most frontal range of the Kuqa depression. Influenced by the subsalt basement tectonics, differential loading and compressional stresses, the halite layers easily flowed from one place to another, and then formed numerous salt-related structures in the Qiulitag structural belt, which had important influences on the hydrocarbon migration and accumulation.The superimposed structural models composed of the subsalt, salt and suprasalt sequences of the Qiulitag structural belt have been carried out using data from seismic profiles interpretation based on the fault-related folding and salt tectonics. In vertical direction, subsalt, salt and suprasalt structures have been classified, and in plane, the differential deformation and segmentation of the salt-related structures are obvious.The Pre-Paleogene basement in the western Qiulitag structural belt appears as a paleo-uplift controlled by basement boundary faults. The basement paleo-uplift initially presented in the Ordovician, and developed during the Silurian to Triassic followed by the termination in the Jurassic. The Pre-Paleogene basement tectonics influenced the development of salt-related structures.According to the balanced cross sections, the salt-related structures mainly formed within the Kuche period to Quaternary. In the Kuqa depression, the SN- striking shortening strains are 20~35 km which occupied the ratio of 20%~35% of the total sections. The different shortening rates in varying tectono-stratigraphic layers and belts are prevalent in the depression where the salt layers could act as detachment and adjusting during the differential deformation of the subsalt and suprasalt layers.On the whole, the salt structures in the northern part of the Kuqa depression formed earlier than those in the south, and the salt structures in the western Qiulitag structural belt also formed earlier, with larger size, and in the eastern portion, the salt structures developed later, with smaller size. The model of elastic-viscous plate indicated that differential loading induced by the thicker sediments in the Baicheng sag dominated in the early stage of salt structural development. At the present, however, the compressional stresses should play largest effects on the salt structures.The physical modelling also showed that the basement faults, paleo-uplift and structural slopes and steps influenced the salt flowage which resulted in the salt thicken on top of the paleo-uplift and the formation of large-scaled north-dipping detachment faults. During the structural distortion, salt bodies acted mainly as the detachment layer and filled the anticline crest, and few salt diapirs formed in the analogue modelling.By the integrated analysis of the influences of salt-related structures on the hydrocarbon migration and accumulation in the Qiulitag structural belt, the reservoir formation models have been documented, and favorable exploration objectives have also been predicted.更多还原