鄂尔多斯盆地富县地区奥陶系风化壳储层特征

发布时间：2018-08-29 09:30

【摘要】：富县区块位于鄂尔多斯盆地东南部,加里东运动使得地层抬升受到剥蚀,形成大规模的古岩溶风化壳。奥陶系岩溶风化壳主力产层为马家沟组马五段。虽然已有油气发现,但储层致密且非均质性强,在不同区域天然气富集程度差别较大,储层研究较为薄弱,有效储层形成机理和分布规律还不够清楚,直接制约了勘探工作进展。鉴于此,对研究区风化壳储层的深入研究势在必行。本文在岩心和镜下薄片观察的基础上,充分利用钻井、测井、录井等资料,并结合试采成果对鄂尔多斯盆地富县地区奥陶系风化壳岩溶古地貌和岩溶储层特征进行了研究。通过地层的划分与对比,明确风化壳地层残存状况;运用“印模法”、“残厚法”并结合古地质图,刻画了风化壳古地貌;利用不同的岩溶相特点进行岩溶相的划分,确定了古岩溶的分布规律;在此基础上对岩溶储层的物性特征、储集空间类型、成岩作用等进行了详细的论述,总结了岩溶储层发育的主要控制因素。论文主要取得了以下研究成果:(1)通过对研究区古地貌的恢复,明确了研究区古地貌主要划分为岩溶高地和岩溶斜坡,古地貌具有西高东低的特征。其中岩溶斜坡是最主要地貌单元,自北向南呈宽阔的带状分布。(2)研究区发育5种岩溶相,裂缝角砾岩相、镶嵌角砾岩相具有低伽马、低中子值、中-高电阻率特点;碎屑支撑紊乱角砾岩相、杂基支撑紊乱角砾岩相、充填砂砾岩相具有中-高伽马、中-低电阻率等特点。(3)岩溶储层非均质性强,在表生裸露期遭受强烈的古岩溶作用,形成大量的溶蚀孔、洞、裂缝等储集空间,经过深埋藏阶段,受压实、充填和胶结作用的影响,会造成孔隙大量损失,储层表现为低孔低渗的特征。(4)岩溶储层发育的主要控制因素有:古地貌因素、岩溶相因素。裂缝角砾岩相和镶嵌角砾岩相较为发育的斜坡台地和斜坡台缘是研究区风化壳岩溶储层发育的有利区域。本文通过大量的取心资料及测井数据,结合以上的研究方法,进一步清晰马家沟组中—下组合岩溶储层特征及其发育的控制因素,对该地区下一步天然气的勘探具有借鉴意义。
[Abstract]:Fuxian Block is located in the southeast of Ordos Basin. The Caledonian movement made the stratum uplift eroded and formed large-scale paleokarst weathering crust. In view of this, it is imperative to study the weathering crust reservoir in the study area. On the basis of core and microscopic thin section observation, this paper makes full use of drilling, logging and logging data, and combines production test results to Hubei province. The karst palaeogeomorphology and karst reservoir characteristics of Ordovician weathering crust in Fuxian area of Erdos Basin are studied.The residual condition of weathering crust is defined by stratigraphic division and correlation.The palaeogeomorphology of weathering crust is depicted by using "impression method", "residual thickness method" and palaeogeo-geological map. On this basis, the physical characteristics, reservoir space types and diagenesis of karst reservoirs are discussed in detail, and the main controlling factors for the development of karst reservoirs are summarized. The main achievements of this paper are as follows: (1) Through the restoration of paleogeomorphology in the study area, the paleogeomorphology in the study area is defined. The karst slope is the most important geomorphic unit, which is distributed in a wide band from north to south. (2) Five kinds of karst facies are developed in the study area, including fractured breccia facies, mosaic breccia facies with low gamma, low neutron value and medium-high resistivity. Chaotic breccia facies, complex base supporting chaotic breccia facies, filling sandy conglomerate facies with medium-high gamma, medium-low resistivity and other characteristics. (3) Karst reservoir heterogeneity is strong, in the supergene bare period suffered strong paleokarstification, forming a large number of dissolved pores, caves, fractures and other reservoir space, through deep burial stage, compacted, filled and cemented. (4) The main controlling factors of karst reservoir development are palaeogeomorphological factors and karst facies factors. Slope platform and slope platform margin where fracture breccia facies and mosaic breccia facies are relatively developed are favorable areas for the development of weathered crust karst reservoir in the study area. A large number of coring data and logging data, combined with the above research methods, further clarify the characteristics of the lower-middle Majiagou formation karst reservoir and its development control factors, for the next step of natural gas exploration in this area has reference significance.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.13

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