考虑酸蚀蚓孔的碳酸盐岩基质酸化产能研究

发布时间：2018-01-08 15:38

本文关键词：考虑酸蚀蚓孔的碳酸盐岩基质酸化产能研究　出处：《西南石油大学》2017年硕士论文　论文类型：学位论文

【摘要】：基质酸化是碳酸盐岩油藏的开发过程中重要的改造和增产手段之一。基质酸化主要通过在适当排量条件下向储层注入活性酸,利用酸液的对流、扩散以及酸岩反应等作用在近井带形成高渗透性的蚓孔,沟通原始地层区域,降低近井带的表皮系数,实现增产。在基质酸化中,前期污染的准确预测、蚓孔的扩展模拟以及蚓孔存在条件下的产能计算是碳酸盐岩油藏基质酸化增产机理研究和效果评价中的重要问题。根据当前研究现状,油井污染预测大多基于油水两相流方程进行模拟计算;蚓孔扩展模型中,较为成熟的是双尺度模型。但是,对于蚓孔存在的酸化区域产能计算大多国内外学者利用平均渗透率进行简化处理,从而推导解析解进行产能计算,该方法忽略了地层的非均质性和蚓孔的非规则生长。因此,建立更加准确的考虑酸蚀蚓孔的产能计算模型对完善基质酸化增产机理研究显得尤为重要。本文以碳酸盐岩基质酸化酸蚀蚓孔扩展规律及其产能计算为研究对象,运用石油工程、油藏数值模拟等领域的相关知识进行了储层污染深度计算、蚓孔扩展规律模拟以及考虑酸蚀蚓孔的产能计算,取得了以下成果:(1)建立了二维径向条件下的泥浆污染深度预测及伤害渗透率计算模型,为后期蚓孔扩展模拟提供数据;(2)利用无因次蚓孔双尺度生长模型,模拟分析了不同相位角及射孔位置条件下的蚓孔扩展规律;同时,建立了考虑酸蚀蚓孔的产能数值计算新方法,将蚓孔扩展模型与油水两相流模型进行联立数值求解进行产能计算;(3)通过本文产能计算新方法,分析了蚓孔长度、蚓孔密度、完井方式等因素对直井酸化产能的影响,明确了蚓孔突破污染带是酸化获得高产的关键因素;且在蚓孔突破污染带时,对于裸眼完井蚓孔密度越小越经济,而对于射孔完井在一定范围内增大蚓孔密度(分支蚓孔数量)却能获得可观的产量增长;针对不同渗透率的储层,模拟计算发现储层渗透率越低,蚓孔的增产效果越明显,低渗透储层的增产倍比主要受主蚓孔的长度所控制。
[Abstract]:Matrix acidification is one of the most important means of improving and increasing production in carbonate reservoir development. Matrix acidification mainly uses acid convection by injecting active acid into the reservoir under appropriate displacement conditions. Diffusion and acidite reaction formed a high permeability wormhole in the near well zone, communicated the original formation area, reduced the epidermal coefficient of the near well zone, and realized the increase of production. In the matrix acidification, the early pollution was accurately predicted. The simulation of wormhole expansion and productivity calculation in the presence of wormhole are important problems in the study of acidizing and increasing production mechanism of carbonate reservoir and the evaluation of its effect. Oil well pollution prediction is mostly based on oil-water two-phase flow equation. In the wormhole expansion model, the two-scale model is more mature. However, most of the scholars at home and abroad use the average permeability to simplify the productivity calculation of the acidified area where the wormhole exists. Thus, the analytical solution is derived for productivity calculation, which ignores the heterogeneity of strata and irregular growth of wormholes. It is very important to establish a more accurate model to calculate the productivity of acidate wormhole in order to improve the mechanism of acidogenic acid acidosis and increase production. In this paper, the expansion law of acid-wormhole and its productivity calculation in carbonate rock matrix acidification are studied. . Based on the related knowledge of petroleum engineering and reservoir numerical simulation, the depth of reservoir pollution, the law of wormhole expansion and the productivity of acid-etching wormhole are calculated. The following results are obtained: 1) the model of mud contamination depth prediction and damage permeability calculation under two-dimensional radial condition is established, which provides data for the simulation of wormhole expansion in later stage. (2) by using the two-scale growth model of dimensionless wormhole, the propagation law of wormhole under different phase angle and perforation position is simulated and analyzed. At the same time, a new method is established to calculate the productivity of wormhole expansion model and oil-water two-phase flow model. 3) through the new method of productivity calculation in this paper, the effects of the length of vermis hole, density of vermis hole and completion method on acidizing productivity of vertical well are analyzed. It is clear that the key factor of obtaining high yield of acidizing is the breakthrough of contamination zone of vermis hole. When the wormhole breaks through the contamination zone, the smaller the density of wormhole is, the more economical it is, but the larger the density of wormhole (the number of branch wormholes) increases in a certain range for perforation completion, the higher the production can be. For the reservoirs with different permeability, it is found that the lower the reservoir permeability is, the more obvious the productivity of wormhole is, and the ratio of increasing production of low permeability reservoir is mainly controlled by the length of the main wormhole.
【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】：TE357.2

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