碳酸盐岩储层酸液滤失机理研究

发布时间：2018-01-20 02:06

本文关键词： 酸化压裂酸液滤失酸蚀蚓孔裂缝网络超临界CO_2　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：碳酸盐岩储层酸压过程中,酸液溶蚀扩展较大的孔隙或天然裂缝形成结构复杂的酸蚀孔缝,导致酸液大量滤失,严重制约了酸压主裂缝的穿透距离。同时酸岩反应生成的CO2等产物使酸液滤失情况更加复杂,因此有必要进一步研究酸液滤失机理,这对于提高酸压效果具有重要意义。本文依托国家科技重大专项任务,首先针对孔隙型碳酸盐岩酸压形成酸蚀蚓孔的情况,建立了酸蚀蚓孔滤失计算模型,对酸压过程中蚓孔内酸液流动反应、蚓孔的溶蚀扩展及游离态CO2效应对蚓孔酸液滤失的影响进行了模拟分析。针对裂缝型碳酸盐岩储层酸压形成酸蚀裂缝的情况,进行了天然裂缝网络酸液溶蚀实验,测试了酸蚀主裂缝沟通分支裂缝的能力及酸液滤失情况。基于单裂缝碳酸盐岩储层酸化的物理模型,根据裂缝内酸液质量守恒及酸液传质平衡建立了天然裂缝内酸液流动反应模型,并对酸压过程中天然裂缝的溶蚀扩展及酸液滤失进行了模拟分析。基于有限元理论,利用等效渗透率方法,以裂缝基质双重介质物理模型为基础,建立了天然裂缝网络等效连续介质滤失模型,模拟分析了天然裂缝网络形态对工作液滤失的影响。在考虑裂缝动态延伸、缝内温度分布、酸岩反应及缝内游离态CO2压缩性影响的基础上,建立了碳酸盐岩储层酸液滤失计算模型,模拟分析了酸蚀孔缝、游离态CO2效应及不同施工条件对酸液滤失及酸压效果的影响。研究表明,游离态CO2的存在降低了酸液滤失量,同时酸液滤失量与施工参数及储层物性有密切的关系,可通过优化相关施工参数降低酸液滤失以提高酸压效果。论文是在考虑游离态CO2、酸蚀孔缝扩展的基础上建立的滤失计算模型具有一定新意,研究成果对现场控滤失、提高酸压效果具有重要的指导作用。
[Abstract]:In the process of acid fracturing in carbonate reservoir, the acid solution corrodes and expands the pore or the natural fracture forms the complex structure of the acid corrosion pore fracture, which results in a large amount of acid fluid filtration. At the same time, the CO2 produced by acid rock reaction makes the acid fluid filtration more complex, so it is necessary to further study the mechanism of acid fluid filtration. It is of great significance to improve the effect of acid compression. In this paper, based on the important special task of national science and technology, firstly, in view of the formation of acid wormhole in porous carbonate rock, a calculation model of acid wormhole filtration is established. The effects of solution propagation of wormhole and free CO2 effect on acid fluid filtration of wormhole were simulated and analyzed. The acid corrosion fracture was formed by acid fracturing in fractured carbonate reservoir. The experiments of acid solution dissolution in natural fracture network were carried out, and the ability of acid corrosion main fracture to communicate branch fracture and acid fluid filtration were tested. Based on the physical model of acidification of carbonate reservoir with single fracture. According to the quality conservation and mass transfer equilibrium of acid solution in fracture, the model of acid fluid flow reaction in natural fracture is established. Based on the finite element theory and the equivalent permeability method, the physical model of dual medium of fracture matrix is used to simulate and analyze the corrosion propagation and acid filtration of natural cracks in the process of acid fracturing. The equivalent continuous medium filtration model of natural fracture network is established, and the influence of natural fracture network shape on working fluid filtration is simulated and analyzed. On the basis of considering the influence of fracture dynamic extension, temperature distribution, acid rock reaction and free CO2 compressibility in carbonate reservoir, a calculation model of acid fluid filtration in carbonate reservoir is established, and the acid-etching pore fracture is simulated and analyzed. The effect of free CO2 and the effect of different construction conditions on acid filtration and acid fracturing. The study shows that the existence of free CO2 reduces the amount of acid fluid filtration. At the same time, the acid filtrate loss is closely related to the construction parameters and reservoir physical properties, which can be reduced by optimizing the construction parameters to improve the acid fracturing effect. In this paper, the filtration calculation model based on free CO _ 2 and acid-etching hole expansion has some new ideas, and the research results have important guiding function for controlling filtration in situ and improving the acid-fracturing effect.
【学位授予单位】：西南石油大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.2

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