【作者】 张惠；

【导师】 蒲仁海；

【作者基本信息】 西北大学 ， 矿产普查与勘探， 2012， 博士

【摘要】 本文在广泛搜集和总结前人的研究成果基础上,综合运用沉积学、石油地质学、储层地质学、测井地质学等理论和最新进展,充分利用钻井、测井、分析化验及动态生产数据等资料,立足鄂尔多斯盆地中生界区域地质背景,着眼盆地南部富县地区长6油层组,全面地分析了延长组地层、沉积体系及浊积岩储层特征。在此基础上,以基本成藏条件分析为手段,开展了烃源岩、盖层及储盖组合、成藏年代及运移条件等多方面研究,最后提出控制本区长6油气富集主要因素,为指导本区进一步油气勘探和其它地区类似油气藏的发现与预测提供理论依据。在长6油层组细分为3个油层亚组的基础上,重点开展各亚组的沉积相、亚相、微相的研究,深入讨论其的特征和时空分布。浊积砂体较细、具有不完整的鲍马序列、见槽模、沟模及火焰状构造、两段式或单段式粒度概率累积曲线和平行于C=M基线的C—M图解等构成本区长6典型浊积沉积的主要特点。区内长6仅发育中扇亚相,进一步划分为浊积水道、浊积水道间、中扇过渡带等3种微相。平面上,主要发育南、北两条浊积水道,各油层亚组浊积水道略有摆动和变化,长63、长62属于浊积扇发育的早～中期的建设期,浊积水道发育,砂体范围广、较厚大,而长6’属于浊积扇发育的晚期,浊积水道逐渐退缩。储层研究表明,长6储层为三角洲前缘滑塌浊积岩的中扇浊积水道沉积砂体,岩性主要为细粒长石砂岩,粒度普遍较细,结构成熟度、成分成熟度都比较低。孔隙类型以粒间孔为主,属于特低孔、特低渗储层,由于沉积微相和成岩作用的差异,使长6浊积岩储层具有较强的宏观和微观非均质性。广泛发育的裂缝不仅改善了储层物性,同时为油气运移提供了良好的通道。长6油藏成藏条件表明,长7烃源岩分布广、厚度大,有机质丰度高,干酪根类型属于Ⅰ—Ⅱ1型,成熟度较高,进入生油高峰期,属于本区好的有效烃源岩；油源对比分析认为,长6油层组原油主要来自长7层烃源岩。长4+5油层组大段泥岩及长6油层组侧向的相变或物性变差构成油气遮挡层。长6油气富集规律研究表明：①丰富的烃源岩为长6油藏的形成提供了物质基础；②沉积微相和砂体发育程度是控制油气分布的决定因素；③良好的封盖、遮挡条件则是油藏形成的关键；④局部鼻状隆起与油藏的形成有一定的关系。长6油藏分布在中扇浊积水道砂体最发育的部位,平面上主要顺浊积水道呈北东向或南西向展布,具有含油砂体分布面积小,连片性差的特点,但在本区局部区域由于砂体厚度大,多期浊积水道砂体的交错叠置,油藏的分布也表现出交错叠置的特点,可以形成较大规模的油田。寻找物性较好的浊积水道砂体及良好盖层,并加强裂缝研究成为下一步研究和勘探的重点。更多还原

【Abstract】 On the basis of collecting and summarizing previous researches, by comprehensive application of theories of sedimentology, petroleum geology, reservoir geology, and logging geology and the latest progress, on the full use of drilling, well logging, and dynamic data of production,based on regional geological background of the Paleozoic of Ordos Basin, focusing on Chang6formation of Southwest Fuxian County of the Ordos Basin, this article comprehensively analysises the Yanchang formation, the sedimentary system, and reservoir characteristics of turbidity. On this basis, taking basic analysis of reservoir forming conditions as the means, this article undertakes the study of hydrocarbon source rock, cap rock and reservoir cap assemblage, reservoir forming time and transport conditions and other aspects, finally puts forward the factors of controlling Chang6oil and gas enrichment. These provide theoretical basis for guiding the further oil and gas exploration and the other similar oil and gas reservoirs" discovery and forecasting in other regions.Chang6formation are subdivided into3subgroups, on this basis.this article focuses on the subgroups’research of sedimentary facies, subfacies, microfacies, deeply discusses the characteristics and the time and spatial distribution. Turbidity sand is fine, with incomplete BaoMa series, slot mode, channel mode and flame structure can be seen in it. Turbidity sand has grain size cumulative probability curves of two sections type or single section type and C-M diagrams paralleling to the C=M baseline, all these constitute the main features of Chang6typical turbidite sedimentary. In this zone, Chang6only develops middle fan subface, furtherly divided into3microfacies which are turbidite channel, the zone between turbidite channels, the transition zone of middle fan. In the plane, it mainly develops two turbidite channels on south to north.Each reservoir subgroup turbidite channels swings and changes slightly. Chang63and Chang62belong to early to middle constructing period of the turbidite fan development, developing turbidite channels, which sand body has a wide range and is thick. Chang61belongs to late period of the turbidite fan development. Its turbidite channels gradually retreat.The study on reservoir shows that Chang6reservoir is depositing sand body in middle fan turbidite channels of the delta front slump turbidity. The lithology is mainly fine-grained feldspathic sandstone, the size is generally small, the structure maturity and composition maturity are relatively low. The pore types are mainly intergranular pores, which belong to the very low porosity and very low permeability reservoir. Due to the differences of sedimentary microfacies and diagenesis, Chang6turbidity reservoir has strong macroscopical and microcosmic heterogeneity. The extensive development of crack not only improves the reservoir property, but also provides good channels for the oil and gas migration.The forming conditions of Chang6reservoir shows that Chang7source rocks has wide distribution, large thickness and high abundance of organic matter, the kerogen types belong to I Ⅱ1type, the kerogen has higher maturity and has entered oil peak, belongs to effective hydrocarbon source rocks of this area; oil and source correlation analysis shows that the crude oil of Chang6oil groups is come from Chang7hydrocarbon source rocks. The mudstone of Chang4+5oil groups and Chang6oil groups lateral phase change or variation of performance form the oil and gas shielding layer.The study of Chang6oil and gas enrichment regularity show that:①the rich source rocks of Chang6reservoir formation provided corporeal basis;②the sedimentary microfacies and the sand body develop degree are the determinant factors of controlling the distribution of oil and gas;③the good sealing and sheltering conditions are the key to the reservoir formation;④the local nose-like uplift has certain relationship with the reservoir formation. Chang6reservoir distributes in the most developed area of the fan turbidite channels sand body, in the plane, it’s mainly spread out from the north to east or from south to west along the turbidite channels, which has the characteristics that oil and sand body distribution has small area and the connection is poor. But in the local area, as the sand thickness is thick, many periods of turbidite channels sand body are staggered and superposed, the reservoir distribution are also exhibiting staggered and superposed characteristics, so these can form large scale oilfield. Looking for the better performance turbidity channel sand body and good cap rocks, and to strengthen the study on cracks become the key to the research and exploration in the next step.更多还原