【作者】 田兵；

【导师】 胡书毅； 杨占龙；

【作者基本信息】 中国石油大学 ， 矿产普查与勘探， 2010， 硕士

【摘要】 通过物源分析、沉积相和沉积体系分析结合储层微观特征分析等方法,本论文对吐哈盆地山前带中下侏罗统的沉积体系和储层特征进行了综合研究。运用重矿物分析和古水流分析方法推断出研究区中下侏罗统发育有南北两大物源体系控制沉积体系的平面展布。北部物源为近端物源,南部物源为较远端物源。采用野外调查与室内研究相结合,综合地质背景、岩性组合、沉积构造及地球化学等的分析资料,推测中下侏罗统主要发育辫状河三角洲、扇三角洲,湖泊、曲流河三角洲以及冲积扇沉积相。整个中下侏罗统发育的有利沉积相砂体是形成优质储层的基础。对研究区开展了沉积体系展布特征及空间演化分析,山前带沉积体系演化经历了八道湾组沉积期的浅水河流-泛滥平原沼泽-滨浅湖体系、三工河组沉积期的浅水三角洲-泛滥平原-滨浅湖体系、西山窑组沉积期的扇三角洲—泛滥平原沼泽—滨浅湖—浅湖沉积体系、三间房组沉积期的的扇三角洲(辫状河三角洲)—泛滥平原—滨浅湖—浅湖体系、七克台组沉积期的的扇三角洲—滨湖砂坝—泛滥平原沼泽—滨浅湖—浅湖沉积体系五个明显不同的演化阶段。通过岩石薄片、铸体薄片、电镜等测试分析资料,研究区储层岩石类型主要为长石岩屑砂岩,其次为岩屑砂岩,成分成熟度明显偏低,胶结物以粘土矿物和碳酸盐胶结物为主,有少量的自生石英等其他矿物。发育的孔隙类型主要为粒内孔,其次为裂缝孔隙及粒间孔。其中裂缝能够大大提高了低渗透砂岩储层的有效渗透率。孔隙结构分为单峰粗孔型、单峰中孔型、单峰细孔型以及单峰微孔型四种类型。研究区内成岩作用主要为压实作用、胶结作用、交代作用以及溶解、溶蚀作用等。山前带断裂活动也较剧烈,断裂的活动对储层的储集空间也有一定的改造作用。成岩阶段主要处于早成岩阶段B期到晚成岩阶段A2期。不同层段不同埋深成岩阶段不同。次生孔隙的发育程度及分布规律主要受沉积作用、成岩作用以及构造作用等因素控制。综合沉积、成岩、物性分析,对山前带中下侏罗统的储层进行了分类和综合评价,研究区主要为低孔特低渗、特低孔特低渗储层,以Ⅱ、Ⅲ类储层为主,但存在一定规模的良好储集层。七泉湖、恰勒坎、核桃沟、鄯勒、柯克亚等构造带中下侏罗统发育优势沉积相带,储层物性较好,且分布广泛,具有良好油气的储集能力,可作为下一步重点勘探目标。更多还原

【Abstract】 The depositional system and reservoir characteristics of the Lower and Middle Jurassic in Bogeda foreland basin were analyzed by applying the techniques of provenance together with depositional system and reservoir micro-characteristics.Sediment of the Lower and Middle Jurassic was deduced to have two provenance systems which came respectively from the north Bogeda foreland and the south provenance by analyzing the heavy mineral assemblage and the distribution of heavy mineral assemblage zone. Relatively, the north provenance was a near-end provenance, and the south provenance was a far-end provenance.The distribution and evolution of sedimentary facies in Bogeda foreland basin is analyzed after dividing the type of depositional system and considering the stack style of sub-succession of strata. We can figure out the types of developed sedimentary facies in this area include braided river deltas, Fan deltas, alluvial fan, meandering river delta and lake facies.Through the sequence-tract mapping of the Lower and Middle Jurassic, the distribution and evolution of depositional systems in different periods have been revealed, including following five stage: a shadow lake-river- floodplain- marsh- shore shallow lake system of Badaowan group,a shadow lake-deltaic-floodplain-shore shallow lake system of Sangonghe group, a Fan deltas- floodplain- marsh- shore shallow lake-shallow lake of Xishanyao group, a Fan deltas(braided river deltas)- floodplain- shore shallow lake-shallow lake of Sanjianfang group, a shore lacustrine-delta- shore shallow lake group.This paper also uses lots of data of conventional rock thin sections, casting slices, scanning election micrographs, mercury injection, for discussing reservoir feathers. Reservoir rocks are mainly feldspathic litharenite, lithic arkose . Grade of maturity of rock structure and contents are low. The sandstone’s cementation matter are mainly mud , carbonate etc, together with minor authigenic quartz.Dissolution pore, constricted fissure and structure fracture are the main reservoir space. Fracture is an important controlling factor for the distribution of reservoirs. The pore structure includes large hole with large throat, medium hole with medium throat, small hole with small throat and small hole with micro-throat. The result shows that there are four diagenetic events which are compaction, cementation, replacement and dissolution in Bogeda foreland basin. Since polyphase tectonic movements and long-term fault activities were experienced, faults are abundant in this sag. The Jurassic fault active period matched well with the hydrocarbon generation and expulsion periods and had an important effect on hydrocarbon migration and accumulation. Diagenetic stage is at from B period of early diagenesis to A2 period of late diagenesis. Developing degree and distribution of secondary pore are controlled by the sedimentation, the diagenesis, the tectonism and so on.Based on the synthetic analysis of sedimentation, diagenesis and reservoir properties, classification and evaluation of reservoir of Bogeda foreland basin are done. The second and the third reservoir dominate in thereservoir of Bogeda foreland basin. The Jurassic reservoirs mainly are pore- type clastic rocks with low porosity and low permeability. The structural zone of Qiquanhu, Qalekan, Shanle, Kekeya and so on have apparent good reservoir conditions horizontally. Vertically, have favorable reservoir properties and good oil-gas accumulation which can be acted as the next exploration focus.更多还原