库车坳陷东部油气成藏特征及有利区带研究

发布时间：2018-04-25 02:31

本文选题：库车坳陷 + 烃源岩　；参考：《中国科学院研究生院(渗流流体力学研究所)》2015年硕士论文

【摘要】：库车坳陷是塔里木盆地油气勘探的重要阵地之一,具备良好的油气成藏条件,拥有丰富的油气资源。本次研究主要利用地球化学理论和方法,辅助以沉积学特征研究,开展了对库车东部中生界烃源岩、天然气以及原油地球化学特征进行了研究,并开展了油气源对比研究。在对油气源对比、油气成藏特征、成藏期次、运聚特征等方面深入分析的基础上,预测了有利勘探区带。侏罗系和三叠系两套煤系泥岩是库车东部的主力烃源岩,两套烃源岩成因类型相似,常规的分析方法和地化指标难以区分。本文利用烃源岩生物标志化合物指标对库车东部烃源岩进行了重新认识,研究发现,侏罗系和三叠系烃源岩均为典型的陆相烃源岩,形成于淡水—微咸水的弱氧化沉积环境,两套烃源岩差异较小,识别难度大。针对库车东部侏罗系和三叠系两套烃源岩类型相似难以区分的问题,本次研究采用烃源岩热模拟的方法来进行判识。烃源岩热模拟轻烃分析发现,库车东部烃源岩热模拟轻烃中的支链烷烃与芳香烃相对含量存在一定差异,并由此建立了该区烃源岩轻烃判识图版,为气源对比提供了新的手段。利用轻烃判识图版,并结合同位素等地球化学参数,对库车东部开展了油气源对比,初步认为库车坳陷东部天然气主要为高成熟演化阶段煤型气,并混有少量油型气,迪北和迪那地区的天然气主要来源于三叠系烃源岩；库车坳陷东部地区原油主要来源于侏罗系烃源岩,油源岩主要为腐殖型烃源岩,以陆相生物有机质输入为主,成烃古环境偏氧化环境。库车坳陷东部气藏为两期成藏,早期以液态烃充注为主,晚期以气态烃充注为主,储层致密时间早于气态烃充注时间,即先致密后成藏,表现为致密气藏的特征。迪北斜坡带和吐格尔明构造带均为大型构造斜坡带,并具有源储大面积叠置连片分布、源充足、储相对致密的特征,具备致密砂岩气藏发育的有利条件,是库车东部目前有利的现实勘探区带。本次研究对于库车坳陷东部侏罗系油气勘探具有重要的理论意义和应用价值,将深化对库车坳陷东部油气富集规律的认识,指导该地区油气的进一步勘探。
[Abstract]:Kuqa depression is one of the important positions for oil and gas exploration in Tarim Basin. It has good oil and gas accumulation conditions and abundant oil and gas resources. The geochemical characteristics of Mesozoic source rocks, natural gas and crude oil in the eastern Kuqa area were studied by means of geochemical theory and method, assisted by the study of sedimentological characteristics, and a comparative study of oil and gas sources was carried out. On the basis of the deep analysis of oil and gas source correlation, oil and gas accumulation characteristics, hydrocarbon accumulation times, migration and accumulation characteristics, the favorable exploration zones are predicted. The Jurassic and Triassic coal series mudstones are the main source rocks in the east of Kuqa. The genetic types of the two sets of source rocks are similar and it is difficult to distinguish the conventional analysis methods from geochemistry indexes. In this paper, the source rocks in the eastern part of Kuqa are rerecognized by using the biomarker index of source rocks. It is found that both Jurassic and Triassic source rocks are typical continental source rocks formed in the weakly oxidized sedimentary environment of freshwater and brackish water. The difference between the two sets of source rocks is small, and it is difficult to identify. In view of the difficulty of distinguishing the similarity between Jurassic and Triassic source rocks in eastern Kuqa, the method of thermal simulation of source rocks is used to identify the source rocks in this study. It is found that the relative content of branched alkanes and aromatic hydrocarbons in the thermal simulation of light hydrocarbons in source rocks in eastern Kuqa is different from that in source rocks, and the light hydrocarbon identification chart of source rocks in this area has been established, which provides a new means for gas source correlation. Using light hydrocarbon identification chart and geochemical parameters such as isotopes, oil and gas source correlation has been carried out in the east of Kuqa. It is preliminarily considered that natural gas in the east of Kuqa depression is mainly coal-type gas of high maturity and evolution stage and mixed with a small amount of oil-type gas. The natural gas in the Dibei and Dinah areas is mainly derived from Triassic source rocks, the crude oil in the eastern Kuqa depression is mainly derived from Jurassic source rocks, the source rocks are mainly humic source rocks, and the main source rocks are terrestrial organic matter. Hydrocarbon generation paleo environment partial oxidation environment. The gas reservoirs in the eastern Kuqa depression are formed in two stages, mainly liquid hydrocarbon filling in early stage and gaseous hydrocarbon filling in late stage. The reservoir densification time is earlier than that of gaseous hydrocarbon filling time, that is, first compaction and then reservoir formation, which is characterized by tight gas reservoir. The Dibei slope belt and the Turgumin structural belt are both large structural slope zones, and have the characteristics of large area superposition of source storage, abundant source and relatively dense reservoir, and have favorable conditions for the development of tight sandstone gas reservoir. Kuqa east of the current favorable exploration zone. This study has important theoretical significance and application value for Jurassic oil and gas exploration in the east of Kuqa depression. It will deepen the understanding of the law of oil and gas enrichment in the eastern part of Kuqa depression and guide the further exploration of oil and gas in this area.
【学位授予单位】：中国科学院研究生院(渗流流体力学研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】