【作者】 侯国伟；

【导师】 于兴河；

【作者基本信息】 中国地质大学（北京） ， 矿产普查与勘探， 2005， 博士

【摘要】 大牛地气田是我国鄂尔多斯盆地北部伊陕斜坡区的一个重要气田,该气田目前已成为国家“西气东输”工程的一个重点供气区块,急需落实气田储量。下石盒子组盒2、盒3 段是大牛地生产区块的主要产层,该气田在实际研究中存在层位对比不清、相带分布不明、含气砂体难于预测等问题,尤其是本区河流相储层分布规律急需解决。针对这些难点,本文从单井出发,充分利用三维地震属性由点到线、由线到面,再到域,进行沉积砂体及微相展布研究,应用科学的相控建模方法,进而建立可靠的储层地质模型,通过多个实现优选预测各层段含气砂层的分布特征,为气田的开发提供科学依据。建立一套适合河流相储层的、可以推广的综合相控建模方法。主要成果与创新如下: 1、明确提出H2、H3 段研究区为辫状河向曲流河的过渡区。主要受地形坡度与水流能量的控制,物源来自于北部。H2 段北部发育辫状河,南部发育曲流河;H3段西部发育辫状河,东部发育曲流河。工区内西部的水体能量强于东部,物源供应西部比东部充足。2、H2 和H3 段河道的变化共有3 种方式:①摆动期:主要形成的沉积环境为辫状河,其水体能量较强,河道横向叠置程度较高,摆动频繁,砂体叠置方式为多层多边式和多层分叉式等;②迁移期:主要形成的沉积环境为低弯度和中弯度的曲流河,其水体能量中等,河道的迁移比较频繁,砂体叠置方式为单边迁移式;③稳定期:主要形成的沉积环境为高弯度曲流河,其水体能量比较弱,河道相对比较固定,砂体叠置方式为孤立式。3、研究层段心滩和边滩是含气砂体发育的微相。为了更好地预测有利砂体的发育部位,避开“以砂找河”的传统思维方式,确定了“以河找砂”的新思路,并系统归纳了河流相的7 种砂体接触关系以及各自的剖面沉积和砂体叠置方式。连井剖面上,北部的砂体比较连片,有效砂层主要呈孤立状分布,主要发育心滩和边滩。4、确定孔隙度5%、渗透率0.1md 为大牛地气田H2 和H3 段有效储层的物性下限。心滩与边滩是主要产气砂体,具有相对较好的储集物性,但非均质性较强。确定了有效厚度、孔隙度、渗透率、非均质性参数和微相等5 个储层评价参数,应用灰色理论科学地确定了各参数的权重,建立了该气田储层的综合权衡定量评价体系。5、根据多信息协同、确定性建模和随机建模相结合的方法建立了本区三维地质模型,先采用针对辫状河和曲流河的科学相控储层建模三步约束思路,即用概率、相序及定量知识库进行分层次逐步约束的方法与步骤。运用序贯指示和序贯高斯模拟方法对相控随机实现进行成控和相控随机建模,并利用多个实现进行对比优选,所建地质模型真实地反映了地下地质体的展布特征。更多还原

【Abstract】 Daniudi gas field is located on the Yi-Shan slope in the north Ordos basin. This gas field is one of the main sources of the national “Transporting gas from the west to the east”project, and thus making sure its gas reserves is very urgent, which will affect the next producing plan. H2 and H3 zone were the main gas producing formation. There are still many problems to be solved, such as the correlation of strata, the facies distribution and the prediction of gas-bearing sandbodies, especially the distribution rule of fluvial reservoir. Focusing on these problems, the paper started with single wells data, and utilized 3-D seismic data to study sandbodies distribution and micofacies distribution, accomplishing from point to plain to field. Using facies-restricted modeling method, the paper established reliable reservoir geological model, optimized several realizations, predicted the distribution of gas-bearing sand, and thus brought about geological modeling methods for fluvial reservoirs. By the dissertation research, results and recognitions were obtained as following: 1. Definitely brought forward that H2 and H3 lied in the transition zone from braided river to meandering river in the research area. Deposition in the area was mainly controlled by gradient and waterpower, and the provenance was from the north. The north H2 developed braided river, while the south H2 developed meandering river. The west H3 zone developed braided river, while the east H3 zone developed meandering river. The energy of the river in the west area was stronger than that in the east area, and the provenance in the west was more abundant than that in the east. 2. Rivers in H2 and H3 experienced three stages: (1) swinging stage: In this stage, the energy of flow was strong, and the research area mainly developed braided rivers. The channels were strongly stacked. And the frequent swinging resulted that the channel sandbodies were stacked as multi-layers and multi-boundaries or multi-layers and branches; (2) migration stage: the energy of the rivers was moderate, and the research area mainly developed meandering rivers of low or moderate sinuosity. The migrations of the rivers were frequent, and thus the sandbodies were staked as migrating on one side; (3) stabilization stage: the energy of the flow was relatively low, and the research area mainly developed meandering rivers of high sinuosity. The channels were relatively stable, which caused isolation of the sandbodies. 3. Channel bar and point bar were the main gas-bearing sandbodies in the research area. To predict the favored sandbodies, a new method was advanced which tried to find out sandbodies by predicting channels, but not to find channels by the known sandbodies. Seven types of stacking relationships of fluvial sandbodies were concluded and their corresponding sedimentary and stacking patters were put forward. 4. It was indicated that 5% and 0.1md were the thresholds for porosity and permeability of prospective reservoirs, respectively. Channel bars and point bars were the main gas producing sandbodies, which had better physical properties, but higher heterogeneity. The five reservoir evaluation parameters, including net-pay thickness, porosity, permeability and microfacies, were used in the comprehensive quantitative evaluation of the reservoir by gray theory.更多还原