粘土矿物对低渗气藏中渗流的影响研究

发布时间：2018-03-01 07:49

本文关键词： 粘土矿物致密气藏气水相对渗透率逾渗微观渗流　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：21世纪是天然气的世纪,随着人类社会对于环保和生态的重视程度不断提高,天然气作为一种高效清洁的能源,受到越来越多的关注。天然气在世界能源结构中的地位也随着天然气的发展稳步上升。但是常规天然气藏储量有限,并不足以满足庞大的市场需求,加速开发非常规天然气资源迫在眉睫。在非常规天然气资源中,低渗致密气占据了很大一部分,但是人们对于低渗致密储层中的气体渗流规律还未形成成熟的理论体系,致密气藏的高效开发还处于摸着石头过河的探索阶段。粘土矿物广泛的存在于砂岩储层中,与气藏整个的开发过程密切相关,对于物性较差的储层的影响更加显著。因此,研究低渗致密气藏中的粘土矿物对于储层中渗流过程的影响对于致密气藏的开发具有指导意义。本文以S气田为研究背景,选取S气田富含粘土矿物的岩样进行实验和理论研究,完成的主要工作如下:1.综合开展饱和称重实验、气测渗透率实验、X射线衍射实验、恒速压汞实验、铸体薄片和扫描电镜实验,设计并建立了适用于低渗岩心且能够在实验过程中保护粘土矿物原生形态的相关实验装置和流程,以此为基础,对岩样的孔渗特征、孔喉分布特征、粘土矿物含量和粘土矿物赋存形态进行了评价和分析。2.改进原有常规岩样的岩心流动评价系统,设计并加装高精度的气水分离计量装置和气体增压泵,开展了室内气—水相对渗透率测试实验研究。3.建立了逾渗孔隙网络模型,从统计角度对气水微观流动过程进行模拟,编制了相应的计算软件。4.实验研究表明,粘土矿物的种类和含量不同对于气田的渗流的影响不同。在粘土矿物含量方面,在保持粘土稳定的条件下,富含伊利石的地层中,随着地层中总粘土含量占总矿物的百分含量的提升,伊利石桥接在喉道中堵塞喉道或是将喉道分割为若干个小喉道的现象越发突出,储层喉道半径分布集中于细小喉道部分,储层物性变差;在富含绿泥石的地层中,随着地层中粘土含量占总矿物的百分含量的提升,大量绿泥石附着在孔隙喉道表面,提高了岩石的亲水性,造成毛管压力增大,气体流通受阻。在粘土矿物类型方面,在保持粘土稳定的条件下,实验中绿泥石和伊利石造成的损害程度相近。
[Abstract]:21th century is the century of natural gas. With the increasing attention of human society to environmental protection and ecology, natural gas as a kind of efficient and clean energy, The status of natural gas in the world energy structure has increased steadily with the development of natural gas. However, the limited reserves of conventional natural gas reservoirs are not sufficient to meet the huge market demand. It is urgent to accelerate the development of unconventional natural gas resources. In the unconventional natural gas resources, low permeability dense gas occupies a large part, but the law of gas seepage in low permeability tight reservoirs has not yet formed a mature theoretical system. The high efficiency development of tight gas reservoir is still in the exploration stage of crossing the river by touching stone. Clay minerals widely exist in sandstone reservoir, which are closely related to the whole development process of gas reservoir, and have more significant influence on the reservoir with poor physical properties. The study of the influence of clay minerals in low permeability tight gas reservoirs on the percolation process in reservoirs is of guiding significance for the development of tight gas reservoirs. The rock samples of S gas field rich in clay minerals are selected for experiment and theoretical study. The main work accomplished is as follows: 1. Comprehensive saturated weighing experiment, gas permeability test, X-ray diffraction experiment, constant velocity mercury pressure experiment, Based on the experiments of casting thin sheet and scanning electron microscope (SEM), an experimental device and flow chart which is suitable for low permeability core and which can protect the primary morphology of clay minerals during the experiment is designed and established. Based on this, the pore and throat distribution characteristics of rock samples are studied. The content of clay minerals and the morphology of clay minerals were evaluated and analyzed. 2. Improving the core flow evaluation system of the original conventional rock samples, designing and installing a high precision gas-water separation metering device and gas booster pump, The experimental study of indoor gas-water relative permeability testing is carried out. 3. The percolation pore network model is established, the microscopic flow process of gas-water is simulated from the statistical point of view, and the corresponding calculation software .4. the experimental study shows that, The types and contents of clay minerals have different effects on the percolation of gas fields. In terms of clay mineral content, in the condition of maintaining the stability of clay, the formation rich in Illite, With the increase of the total clay content in the strata, the phenomenon that the Illite bridge is connected to the throat to block the throat or divide the throat into several small ones is becoming more and more prominent, and the radius of the reservoir throat is concentrated in the small throat. The reservoir physical properties become worse, in the chlorite rich formation, with the increase of clay content in the formation, a large amount of chlorite is attached to the pore throat surface, which improves the hydrophilicity of the rock and increases the capillary pressure. In terms of clay mineral type, the damage caused by chlorite and Illite in the experiment is similar under the condition of maintaining the stability of clay.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE312

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