鄂尔多斯盆地延长区盒8天然气藏控制因素研究

发布时间：2018-05-27 04:36

本文选题：鄂尔多斯盆地 + 盒8段　；参考：《西安石油大学》2015年硕士论文

【摘要】：研究区位于陕北斜坡南部,构造特征为一平缓的西倾单斜,地层倾角小于1°,地层稳定,构造简单。本区屮二叠统石盒子组盒8段属于三角洲前缘亚相沉积,根据Sr/Ba值、B/Ga值、硼含量判断其沉积环境属于淡水一微盐水环境。三角洲前缘的水下分流河道砂体是盒8段天然气的主要储集体,岩性主要为石英砂岩及岩屑砂岩,压实作用和胶结作用大大降低了储层的孔隙度和渗透率,而溶蚀作用则产生了次生溶蚀孔隙,使储层物性得到了改善,总体来说盒8储层属于特低孔、特低渗储层。近距离运移、多层段聚集是鄂尔多斯盆地陕北斜坡地区上古生界天然气主要的成藏方式。下伏本溪组、太原组、山西组的煤系气源岩是盒8气藏主要的烃源岩。上倾致密层及侧向漫滩泥质岩形成的岩性圈闭是研宄区主要的圈闭类型。鄂尔多斯盆地上古生界泥岩普遍存在由于“欠压实”产生的剩余压力,通过泥岩声波时差与深度关系图可以发现过剩压力最大出现在上石盒子组下部泥岩段,成为盒8天然气藏的直接盖层。运用等效深度法做出研究区盒8泥岩过剩压力分布图,结合砂厚、沉积相、储层物性总结了研究区盒8气藏的控制因素。结果表明,己勘探发现的盒8段天然气分布范围大部分出现在剩余压力较低的范围内,同时受沉积相、优质储层、圈闭有效性等多重因素控制。
[Abstract]:The study area is located in the southern part of the slope of northern Shaanxi. Its structural characteristics are a gentle westward inclination with a dip angle of less than 1 掳, stable strata and simple structure. Bo8 member of Shihezi formation belongs to delta front subfacies deposition in this area. According to the Sr/Ba value and B / Ga value, boron content indicates that the sedimentary environment belongs to freshwater and micro-brine environment. The subaqueous distributary channel sand body in front of delta is the main reservoir of natural gas in Bo8 formation. The lithology is mainly quartz sandstone and lithic sandstone. Compaction and cementation greatly reduce the porosity and permeability of reservoir. The dissolution resulted in secondary dissolution porosity, which improved the physical properties of reservoir. Generally speaking, Bo8 reservoir belongs to ultra-low porosity and ultra-low permeability reservoir. Close migration and multilayer accumulation are the main reservoir forming methods of Upper Paleozoic natural gas in northern Shaanxi slope area of Ordos Basin. The coal measures gas source rocks of Xiafubengxi formation, Taiyuan formation and Shanxi formation are the main hydrocarbon source rocks in Box 8 gas reservoir. The lithologic traps formed by the updip dense layers and lateral muddy rocks are the main types of traps in the study area. The residual pressure of the Upper Paleozoic mudstone in the Ordos Basin is generally due to the "undercompaction". The excess pressure is found to be the largest in the lower mudstone section of the Upper Shihezi formation through the diagram of the relationship between the sonic time difference of the mudstone and the depth of the mudstone. Become the direct cap of box 8 natural gas reservoir. By using the equivalent depth method, the excess pressure distribution map of block 8 mudstone in the study area is made, and the controlling factors of box 8 gas reservoir in the study area are summarized with the combination of sand thickness, sedimentary facies and reservoir physical properties. The results show that the distribution range of natural gas in Bo8 member is mostly within the range of lower residual pressure, which is controlled by many factors, such as sedimentary facies, high quality reservoir, trap validity and so on.
【学位授予单位】：西安石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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