鄂尔多斯盆地南部侏罗系油砂地质特征及成藏模式

发布时间：2018-05-12 01:06

本文选题：鄂尔多斯盆地 + 渭北隆起带　；参考：《吉林大学》2015年硕士论文

【摘要】：油砂作为继常规原油之后的一种重要的能源，具有巨大的勘探开发前景，中国的油砂资源非常丰富且分布广泛，但对油砂的地质背景、资源潜力等方面的总体认知程度仍比较低。鄂尔多斯盆地作为我国重要的能源基地，已探明丰富的石油、天然气、煤、铀矿等资源，而对盆地油砂资源的勘探工作仍处于相对空白的状态，本论文依托于中国地质调查局油气资源调查中心《全国油砂成矿远景及选区研究》和《我国西北地区油砂资源成藏潜力研究》项目，以鄂尔多斯盆地南部渭北隆起的庙湾-宜君地区侏罗系直罗组、延安组油砂为主要的研究对象。在研究区野外地质调查和实测油砂露头剖面的基础上结合油砂科探井所获得的资料及室内薄片镜下观察，明确研究区油砂地质特征、分布特征，沉积特征；通过收集掌握前人研究资料和对油砂样的地化测试分析来研究庙湾-宜君地区侏罗系油砂的烃源岩；通过对地表及井下的油砂样的显微镜（包括光学显微镜及扫描电镜）下观察及相关地化测试分析来评价油砂储层的物性条件。最后再系统研究油砂矿藏形成过程，时空分布规律及成矿主控因素，建立鄂尔多斯盆地南部侏罗系油砂矿藏的成藏模式。庙湾-宜君地区广泛分布侏罗系直罗组、延安组地层，直罗组下部地层和延安组的煤系地层以上部分出露地表较全，地层走向270°-300°，倾角15-25°，含油砂岩岩性以长石砂岩和长石石英砂岩为主，通常粗粒砂岩含油性较细粒砂岩要好，含油级别最高达油浸。通过实测剖面和钻井综合柱状图的岩性组合关系与岩样室内光学薄片鉴定和粒度分析：直罗组主要为河流相沉积，以辫状河沉积体系为主，亚相主要为河道砂坝及河漫滩，局部地区发育湖泊相沉积，亚相为浅湖相和滨湖相；延安组主要为河流相和湖泊相沉积，河流相主要为曲流河沉积体系，，亚相为河漫和河床（道），湖泊相可识别出半深湖、浅湖和滨湖3个亚相。鄂尔多斯盆地南部庙湾-宜君地区油砂遭受严重的氧化、风化剥蚀、生物降解作用。研究区油砂岩体主要有粒间孔、粒内溶孔、裂缝、晶间微孔这四类主要的孔隙类型。通过实测物性分析，直罗组、延安组储层均为低孔低渗储层。鄂尔多斯盆地南部侏罗系油砂成藏有利条件：①通过对侏罗系油砂原油的物性分析、碳同位素及生物标志化合物的对比，证明研究区侏罗系油砂原油来自三叠系延长组湖相烃源岩；②延安组、直罗组河流相砂岩较好的储集物性为原油的聚集提供良好的储集空间；③构造控制着油砂矿藏的形成。鄂尔多斯盆地渭北隆起油砂在成藏的过程与构造演化密切相关，因此其成藏模式属于抬升运移型。三叠系烃源岩在侏罗纪末期开始生油，至白垩纪末达生油高峰，同期渭北地区整体构造抬升并形成断层、褶曲等构造，使油气向上运移至侏罗系地层大规模成藏，随着隆起带进一步抬升使上部地层遭受剥蚀，油气藏逐渐靠近甚至出露至地表而形成油砂。
[Abstract]:As an important source of energy after conventional crude oil, oil sand has a great prospect of exploration and development. China's oil sand resources are very rich and widely distributed, but the overall cognition of the geological background and resource potential of oil sand is still low. Ordos Basin is an important energy base in China, and it has proven rich stone. Oil, natural gas, coal, uranium ore and other resources, and the exploration work of oil sand resources in the basin is still in a relatively blank state. This paper is based on the China Geological Survey oil and gas resource survey center, the national oil sand metallogenic prospect and selected area research and the research project of the reservoir potential of oil sand resources in Northwest China, and the southern Wei of the Ordos Basin. The oil sand of the Yanan formation is the main research object in the Jurassic Jurassic formation in miwan Yijun area of the northern uplift.
On the basis of field geological survey and measured oil sand outcrop section in the study area, the geological characteristics, distribution characteristics and sedimentary characteristics of the oil sand in the study area are clearly defined in combination with the data obtained from the oil sands exploration well and the observation under the indoor thin film microscope. The hydrocarbon source rocks of the Jurassic oil sand; evaluate the physical properties of the oil sand reservoir by observation and related geochemical analysis under the microscope (including optical and scanning electron microscopy) on the surface and underground oil sand samples. Finally, the formation process of oil sand deposits, the spatial and temporal distribution and the main controlling factors of the ore-forming process are systematically studied, and the Ordos Basin is established. The reservoir forming model of the Jurassic oil sand deposits in the south.
The Jurassic zluo group is widely distributed in the mian Bay Yijun area. The Yanan formation, the lower strata in the lower dioluo formation and the coal measures in the Yanan formation are fully exposed. The strata trend to 270 degree -300 degrees, and the dip angle is 15-25 degrees. The lithology of the oil sand rocks is dominated by feldspar sandstone and feldspar quartz sandstone, and the oil bearing sandstone contains more oil than fine sandstone and oil containing oil. The highest level of oil is in oil.
According to the lithologic assemblage relation of measured profile and comprehensive drilling histogram, and the identification of optical thin slice and grain size in the interior of the rock sample, the main is the river facies deposit, with the braided river sedimentary system mainly, the subfacies is mainly the river sand bar and the river flood beach, the lake facies is deposited in the local area, the subfacies is the shallow lake and Binhu facies, and the Yanan group is the main part. The river facies and lake facies should be deposited, the main river facies is the meandering river sedimentary system, the subfacies is the river man and the river bed. The lake facies can identify the 3 subfacies of the half deep lake, the shallow lake and the Binhu.
The oil sands in miwan Yijun area of the southern Ordos Basin suffered severe oxidation, weathering and denudation and biodegradation.
The oil sand body in the study area mainly consists of four types of main pore types: intergranular pore, intragranular hole, crack and intergranular micropore. The reservoir of Yanan formation is low porosity and low permeability reservoir through measured physical property analysis.
The favorable conditions for the Jurassic oil sand formation in the southern Ordos Basin are as follows: (1) through the analysis of the physical properties of Jurassic oil sand, carbon isotopes and biomarker compounds, it is proved that the Jurassic oil sand crude oil from the Triassic Yanchang Formation lacustrine source rock; (2) the Yanan formation and the good reservoir property of the river facies sandstone of the di Luo formation is the original. The accumulation of oil provides good storage space; (3) the structure controls the formation of oil sands.
The process of oil sand in the Weibei uplift of the Ordos Basin is closely related to the tectonic evolution. Therefore, the reservoir forming model belongs to the uplift migration type. The Triassic source rocks began to oil in the late Jurassic period and reached the peak of the oil generation at the end of the Jurassic period. The whole structure of the Weibei area was uplifted and formed into faults and folds, and the oil and gas moved upward to the upper part of the Weibei region. The Jurassic strata are massive reservoirs. With the further uplift of the uplift zone, the upper strata are eroded, and the oil and gas reservoirs are gradually approaching or even exposed to the surface to form oil sands.

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

【参考文献】