鄂尔多斯盆地苏14井区盒8段沉积微相与储层宏观非均质性研究

发布时间：2018-04-19 04:39

本文选题：鄂尔多斯盆地 + 苏14井区　；参考：《成都理工大学》2015年硕士论文

【摘要】：苏14井区是苏里格气田重要的资源勘探区域,主要的产气层为下石盒子组盒8段,储集砂体为大型缓坡浅水河流相三角洲沉积,三角洲砂体分布广泛,但砂体横向分布极不连续,纵向相互叠置,含气砂岩难以识别,含气范围定量标准不易确定,储层非均质性强,严重影响了该地区天然气开发效果。基于上述问题,本论文在前人研究基础上,通过岩心观察、地球物理测井资料、地震资料及地球化学资料分析,运用沉积学、储层地质学、石油地质学等理论方法为指导,系统的研究了苏14井区盒8段砂体的沉积微相及储层宏观非均质性特征,通过精细描述砂体规模、纵向叠置关系、横向展布特征和储层的空间变化规律,取得了以下几点认识:(1)综合岩石颜色、岩石结构、构造和古生物及地球化学古盐度的研究内容,推测盒8段为季节性干旱的陆相-海陆过渡相的浅水河流沉积环境。依据剖面结构和测井相、地震相标志,认为MSC1-MSC3中期旋回发育辫状河的三角洲平原沉积,沉积微相为分流河道和分流间洼地;MSC4中期旋回发育曲流河的三角洲平原沉积,沉积微相为天然堤、决口扇、分流河道、分流间洼地。(2)MSCI、MSC2中期旋回砂体为多期辫状分流河道的叠置,厚度大,砂体在平面上呈毯式近南北向大面积展布;MSC3中期旋回砂体延伸规模较小,厚度较薄,平面砂体带宽度较MSCI、MSC2中期旋回小;MSC4中期旋回砂体横向延伸规模减小,厚度薄,垂向泥质夹层和隔层增多,砂体多呈孤立状分布,在平面上呈南北向细条带状展布。MSC1-MSC3中期旋回的辫状河三角洲平原砂体横向上分流河道砂体分布性好,侧向相互叠置的砂体之间常常被细粒砂岩和泥岩分隔,限制了砂体横向上的连续性和连通性,因此单个河道储集砂体能够形成的气藏各自相对独立,多个河道储集砂体的存在能够形成多个相对独立的气藏同时存在;MSC4中期旋回曲流河三角洲平原砂体由于分流间洼地的大面积分布导致河道相互分割,因此阻碍了砂体之间的连通性,但在不同时期沉积的多个分流河道砂体在垂向上不间断的叠置发育,仍能形成有利的储集砂体。(3)储层宏观非均质性的研究表明整个盒8段砂岩储层表现出较强的非均质性。MSC1中期旋回砂体连通性最好,分层系数和砂岩密度高,夹层发育较少,物性条件中等但均质性好,非均质性最弱;MSC2中期旋回砂体连通性较好,分层系数和砂岩密度较高,夹层发育较少,物性条件及均质性中等,非均质性较弱;MSC3中期旋回砂体连通性较差,分层系数和砂岩密度较低,夹层发育较少,物性条件及均质性中等,非均质性较强;MSC4中期旋回砂体连通性最差,分层系数低和砂岩密度低,发育有较多夹层,物性条件中等但均质性较差,非均质性最强。
[Abstract]:Su-14 well area is an important resource exploration area in Sulige gas field. The main gas producing reservoir is the No. 8 member of Lower Shihezi formation. The reservoir sand body is a large shallow water fluvial delta deposit with a wide distribution of delta sandbodies.However, the transverse distribution of sand bodies is extremely discontinuous, the vertical overlay is superimposed, the gas-bearing sandstone is difficult to identify, the quantitative standard of gas-bearing range is difficult to determine, and the reservoir heterogeneity is strong, which seriously affects the natural gas development effect in this area.On the basis of previous studies, this paper is guided by core observation, geophysical logging data, seismic data and geochemical data, as well as the application of sedimentology, reservoir geology, petroleum geology and other theoretical methods.The sedimentary microfacies and macroscopic heterogeneity characteristics of sand bodies in Bo8 member of Su-14 well area are systematically studied. The size of sand bodies, vertical overlay relations, horizontal distribution characteristics and spatial variation of reservoirs are described by fine description of sand body size, vertical overlay relationship, horizontal distribution characteristics and reservoir spatial variation.The study contents of color, structure, structure, paleontology and geochemical paleosalinity of rocks have been obtained as follows. It is inferred that member 8 is a shallow river sedimentary environment of seasonal arid transitional facies from land to sea and land to land.According to the profile structure, logging facies and seismic facies, it is considered that the delta plain deposits of braided rivers are developed in the middle MSC1-MSC3 cycle, and the sedimentary microfacies are delta plain deposits of the meandering rivers developed in the middle cycle of MSC4, the distributary channel and the interdistributary depressions.The sedimentary microfacies are natural embankment, crevasse fan, distributary channel, interdistributary depressions. MSCI / MSC2 middle cycle sand body is superimposed by braided distributary channel in many periods, and its thickness is large.On the plane, the sand body is distributed in a large area near the north and south direction. The extension scale of the cyclic sand body in the middle period of MSC3 is smaller and the thickness is thinner. The width of the sand body in the plane is smaller than that in the middle cycle of MSC2. The transverse extension scale of the sand body in the middle cycle of MSC4 is smaller than that in the middle cycle of MSC4, and the thickness of the sand body is thin.The vertical muddy intercalation and interlayer increase, the sand bodies are mostly distributed in isolated shape, and the distributary channel sand bodies are distributed in the horizontal direction of the braided river delta plain sand bodies in the middle cycle of MSC1-MSC3.The lateral superimposed sand bodies are often separated by fine-grained sandstone and mudstone, which limits the continuity and connectivity of the sand bodies laterally, so the gas reservoirs that can be formed by a single channel reservoir are relatively independent.The existence of multiple channel reservoir sand bodies can form several relatively independent gas reservoirs and there is also a middle MSC4 cycle meandering river delta plain sand bodies due to a large area distribution of distributary depressions leading to the division of river channels.Therefore, the connectivity between sand bodies is hindered, but many distributary channel sandbodies deposited in different periods are superimposed vertically and continuously.The study of macroscopic heterogeneity of reservoir can still form favorable reservoir sand body. 3) the study shows that the sandstone reservoir of the whole box 8 member shows strong heterogeneity. MSC1 middle cycle sand body connectivity is the best, the stratification coefficient and sandstone density are high, and the intercalation is less developed.The physical property condition is medium but the homogeneity is good, the heterogeneity is weakest, the connectivity of cyclic sand body is better, the stratification coefficient and sandstone density are higher, the intercalation development is less, the physical property condition and homogeneity is medium,In the middle period of MSC3, the connectivity of sand bodies is poor, the stratification coefficient and sandstone density are lower, the intercalation is less, the physical properties and homogeneity are moderate, and the connectivity of the sand bodies in the middle cycle of MSC4 is the worst.The stratification coefficient is low, the sandstone density is low, there are more interlayers, the physical property condition is medium but the homogeneity is poor, and the heterogeneity is the strongest.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P618.13

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