缝洞型油藏注水压降试井解释方法研究

发布时间：2018-01-24 03:06

本文关键词： 碳酸盐岩缝洞单元数学模型物质平衡方程试井分析　出处：《西南石油大学》2015年硕士论文　论文类型：学位论文

【摘要】：缝洞型碳酸盐岩储层是一种普遍发育次生裂缝和溶洞的特殊储层空间,其渗流机理与常规碎屑岩储层有较大区别,因此使用常规解析试井方法并不适合对其进行动态分析。本论文充分考虑塔河油田碳酸盐岩储层特点,从地质概念模型出发,着眼于整个缝洞单元物质平衡关系,不再用连续介质场方法描述缝洞型储层,建立了描述注水压降试井过程井底压力变化的数学表达式。并通过残差分析法和图解法求取了表达式中各个参数,分析了不同参数对缝洞型储层注水压降试井曲线形态的影响。并运用所得成果,分析了塔河油田12区2010年至2014年的注水压降试井资料,求出单井控制的储集体体积、裂缝系统等效渗透率等相关参数,为后期注水替油失效井治理提供了理论依据。通过与实际数据对比发现,使用本文研究成果对油藏动态分析所得到的结果具有较高精度。本文在研究过程中取得了如下成果： (1)通过对塔河油田碳酸岩储层的地质资料及相关生产数据的分析得出塔河油田缝洞型碳酸岩储层主要是由裂缝、溶洞和几乎不具有孔渗性的基岩组成的多重介质,该种多重介质在空间上具有强烈的非连续性； (2)通过分析塔河油田典型井注水压降试井资料,得出了塔河油田碳酸盐岩储层注水压降试井过程中压力损耗主要在关井初期,关井初期压力随时间变化速率快,体现在试井曲线中表现为关井初期曲线切线斜率大。而后期压力随时间的变化率逐渐减小,在试井曲线中表现为曲线斜率逐渐减小,最终趋近于零的特征。观察缝洞型碳酸盐岩注水压降试井曲线形态与传统双重介质解析试井理论曲线形态有较大差异,主要表现为实测压降试井数据在半对数图上不显示出明显窜流段也观察不到平行直线段,有别于常规双重介质试井结果,反映了在井底附近存在非均质裂缝和不连续溶洞,说明塔河油田缝洞型油藏储集体渗透性分布的强非均质性及储集体的非连续性； (3)通过对常规解析试井分析方法中连续介质场理论适用条件的调研发现,由于常规油藏数值模拟软件所使用的数学模型存在对地层简化程度过高,描述缝洞单元的数据体精度不够等原因,导致不能准确模拟缝洞型储层的注水压降曲线。即便使用均匀裂缝连续介质模型,也因为对裂缝系统展布规律的过度简化,导致难以准确模拟实际缝洞型碳酸盐岩油藏注水压降过程； (4)提出了裂缝—溶洞型非连续介质注水压降试井资料的分析方法,分析计算了各单井控制的缝洞单元体积及裂缝渗流能力等指标。
[Abstract]:Fracture and cavernous carbonate reservoir is a kind of special reservoir space where secondary fractures and caverns are widely developed, and its percolation mechanism is quite different from that of conventional clastic rock reservoirs. Therefore, the conventional analytical well testing method is not suitable for dynamic analysis. This paper fully considers the characteristics of carbonate reservoir in Tahe Oilfield, starting from the geological concept model. Focusing on the material balance relation of the whole fracture-cavity unit, the continuous medium field method is no longer used to describe the fracture-cavity reservoir. A mathematical expression describing the change of bottom hole pressure in the process of water injection pressure drop test is established, and the parameters in the expression are obtained by residual analysis method and graphic method. This paper analyzes the influence of different parameters on the shape of injection pressure drop well test curve in fractured and cavernous reservoir, and analyzes the injection pressure drop well test data from 2010 to 2014 in Tahe Oilfield from 2010 to 2014 using the obtained results. The relative parameters such as reservoir volume controlled by single well, equivalent permeability of fracture system and so on are obtained, which provide a theoretical basis for the treatment of oil failure wells with water injection in the later stage, and are found by comparison with actual data. The results obtained in this paper have high accuracy for reservoir performance analysis. In the course of the research, the following results have been obtained: 1) through the analysis of geological data and related production data of carbonate reservoir in Tahe Oilfield, it is concluded that fracture is the main type of carbonate reservoir in Tahe Oilfield. There is strong discontinuity in the space between the cavern and the multilayer medium consisting of the bedrock which has almost no porosity and permeability. 2) by analyzing the test data of water injection pressure drop in typical wells in Tahe Oilfield, it is concluded that the pressure loss of water injection pressure drop well in carbonate reservoir of Tahe Oilfield is mainly in the early stage of shutoff. The change rate of the initial pressure with time is fast, which is reflected in the well test curve, which shows that the tangent slope of the initial curve is large, while the rate of change of the later pressure decreases with time. In the well test curve, the slope of the curve gradually decreases, and finally approaches to zero. The observation of fracture-cavity carbonate injection pressure drop curve shape and the traditional dual medium analytical well test theory curve shape is quite different. The main performance is that the measured pressure drop well test data do not show obvious channeling section nor parallel straight line section on the semi-logarithmic diagram, which is different from the conventional dual medium well test results. It reflects the existence of heterogeneous fractures and discontinuous caverns near the bottom of the well, which indicates the strong heterogeneity of reservoir permeability distribution and the discontinuity of reservoir mass in the fracture-cavity reservoir of Tahe Oilfield. Through the investigation of the application conditions of continuum field theory in the conventional analytical well testing analysis method, it is found that the mathematical model used in the conventional reservoir numerical simulation software has a high degree of simplification to the formation. The data volume accuracy of the fracture-cavity unit is not accurate enough to accurately simulate the water-injection pressure drop curve of the fracture-cavity reservoir, even if the uniform fracture continuum model is used. It is also difficult to accurately simulate the process of water injection pressure drop in the actual fractured carbonate reservoir because of the over-simplification of the distribution law of fracture system. (4) the analysis method of pressure drop test data of fracture-cavern discontinuous medium is put forward, and the volume of fracture-cavity unit and fracture percolation ability controlled by each single well are analyzed and calculated.
【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】：TE353

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