【作者】 修乃岭；

【导师】 熊伟；

【作者基本信息】 中国科学院研究生院（渗流流体力学研究所） ， 流体力学， 2008， 硕士

【摘要】 随着我国能源需求的不断增加和油气勘探的深入,非常规油气藏的勘探开发显得越来越重要。缝洞型碳酸盐岩油藏由于储量规模大,且具有较高的产能,对我国的石油战略具有重要意义。与常规的碎屑岩油藏不同,碳酸盐岩油藏最突出的问题是极强的非均质性和缝洞本身的多尺度性和连通多样性,这使得该类油气藏的开发非常困难,目前国内外在缝洞型油藏开发方面还没有形成相应的开发理论和开发方法,导致这类油藏难以开发或者开发水平低。发展与建立碳酸盐岩缝洞型油藏流体流动动力学理论,是实现碳酸盐岩缝洞型油气藏科学开发的理论基础。首先,利用NMR核磁共振、CT扫描,气测渗透率等手段对塔河油田岩心进行了系统研究,对缝洞型碳酸盐岩储层性质有了更深刻的认识,认为微细裂缝为岩心的主要储渗空间,基质没有储渗能力;其次,从基本的单缝洞出发,开展了单缝洞中不同流动速度下实验和数值模拟研究,探索大裂缝溶洞中流体流动规律,为建立缝洞型碳酸盐岩储层流体流动方程提供支持。结果表明,裂缝中的流速越大,溶洞中涡流越强,引起了附加流动阻力也越大。将实验结果和数值模拟结果比较发现,大裂缝溶洞中流体流动符合流体力学规律;最后,根据缝洞型碳酸盐岩储层的特征,提出将缝洞型储层分为大裂缝溶洞系统和微细裂缝系统,大裂缝溶洞内不考虑多孔介质,流体流动属于自由流动,并可以简化为管道流动;微细裂缝为渗流区,流体流动规律符合Darcy定律。在实验和理论分析的基础上,结合流体力学和渗流力学知识,建立了管流-渗流耦合物理模型、数学模型和数值求解方法,计算了封闭油藏衰竭开采的特征和解释了含水率间歇变化规律,计算了缝洞中压力分布和底水油藏单井连通不同缝洞系统时含水率上升规律。结果表明裂缝中压力降落远大于溶洞中压力降落,底水油藏单井连通不同缝洞系统时,含水率呈现台阶式上升,与现场数据具有较强的一致性。本文的创新之处在于:(1)开展了缝洞型碳酸盐岩油藏储层特征研究,实验结果表明基质不能作为有效储层,岩心的储渗能力由微裂缝提供,因此,将储层划分为大裂缝溶洞系统和微细裂缝系统,而不是传统的三重介质。(2)结合流体力学和渗流力学知识,建立了管流—渗流耦合模型,计算了缝洞中压力分布规律,还计算了注水开发或底水油藏条件下,单井连通不同缝洞系统时含水率的上升规律。更多还原

【Abstract】 In company with our country’s increasing energy demand, the exploration and development of unconventional reservoirs became more and more important. Because of its large reserve volume and high productivity, naturally fractured vuggy carbonate reservoirs are signified to our national petroleum strategy. Be different with conventional classic reservoirs, the most outstanding problem of fractured vuggy carbonate reservoirs are extreme heterogeneity and the various scales of fracture and vuggy fabric and multifold connection. All these made a great deal of difficulty in the development of carbonate reservoirs. By now, there is no efficient method of development of this kind of reservoir home and abroad. So in order to provide the technique support for developing the reservoir scientifically, it is essential to carry on the percolation mechanism research of naturally fractured vuggy carbonate reservoirs.Firstly, the character of the core of Tahe oil field is systematically studied based on NMR, CT scanning technique, and much profound knowledge of fractured vuggy carbonate reservoir is acquired. Secondly, The single-phase flow in fracture and cave is studied on the base of numerical computation and experiment. The flow law , which can provide theoretical support to establish flow equation of fractured vuggy carbonate reservoir, is studied . Result showed that swirl in the cave will be bigger if flow velocity is faster. Based on the experiment result and numerical simulation result, we can know that the law of flow in fracture and cave is accordance with fluid mechanics equation. Lastly, in accordance with the characteristics of fractured vuggy carbonate reservoir, a basic idea for studying the flow law in this kind of media is put forward: this kind of fractured vuggy reservoir system is decomposed into big fracture vug units and microscopic fracture and corroded hollow units, and in the big fracture vug units there not exists porous media, the fluids belongs to free flow and can be simplified to tube current.; the law of flow of minute crack and corroded hollow is accordance with Darcy’s law. The numerical model is put forth and calculated through projection method. Flow field in fracture and cave is obtained and distribution of pressure and velocity is also given in this paper. Numerical computation and experiment show that the flow from fracture to cave is similar to jet flow if the velocity is big enough. A new hydrodynamic model, which is based on the tubing flow theory, is put forth in this paper. Exploitation performance and water cut changes are also simulated in this paper.Innovates of this paper are as follows:(1) The characteristics of carbonate reservoir are studied, and experimental results show that matrix can not be as effective reservoir, store ability and permeability of the rock core are provided by micro fracture, so the reservoir is divided into macro fracture system and micro fracture system, not the classical triple-medium.(2) A new coupled hydrodynamic model, which is based on the tubing flow theory and knowledge of seepage , is put forth in this paper, the pressure distribution is calculated, Exploitation performance and water cut changes are also simulated in this paper.更多还原