基于分形理论的聚合物驱试井分析

发布时间：2018-07-26 11:54

【摘要】：聚合物驱为维持我国原油产量做出了巨大贡献。现场注聚发现,聚合物溶液高粘度及吸附滞留造成地层堵塞,井底压力上升,注入量下降,部分井周围地层产生微裂缝。近年来,各大油田采取压裂解堵增注技术,缓解了聚合物溶液压力上升和注入量低的问题。因此,研究地层微裂缝和人工压裂裂缝对聚合物溶液注入能力的影响对指导聚合物驱具有重要意义。本文在调研国内外聚合物驱渗流机理的基础上,建立了考虑粘弹性和机械降解效应的聚合物溶液有效粘度模型,通过概念模型计算发现聚合物溶液粘弹性及机械降解效应仅发生在近井地带,聚合物溶液在大范围内仍保持剪切变稀流变性。利用分形理论研究微裂缝对聚合物溶液渗流的影响,建立了基于分形理论的聚合物驱二区复合、三区复合、双重介质二区复合非稳态渗流模型;用双线性流分析方法建立了有效导流垂直裂缝井二区复合油藏聚合物驱非稳态渗流模型。用Stehfest数值反演方法和有限差分方法对模型进行了求解,绘制了典型曲线,对曲线形态进行了分析。聚合物溶液注入能力的评价指标主要有注入指数、Hall曲线、Hearn曲线等,这些方法与现代生产动态分析方法有异曲同工之妙,主要目的都是研究聚合物溶液注入量和压力随时间变化的规律,进而获取一些物性参数。因此,根据建立的聚合物驱非稳态渗流模型,引入物质平衡时间,分别建立了四种模型的Agarwal—Gradner、NPI和Transient注入能力分析图版,分析了曲线形态及参数敏感性。
[Abstract]:Polymer flooding has made a great contribution to maintaining crude oil production in China. It was found that high viscosity and adsorption retention of polymer solution resulted in formation blockage, bottom hole pressure rising, injection volume decreasing, and microfractures in the formation around some wells. In recent years, pressure cracking plugging and injection increasing technology has been adopted in various oilfields to alleviate the problem of pressure rise and low injection rate of polymer solution. Therefore, it is important to study the influence of formation microfracture and artificial fracturing fracture on polymer solution injection ability. On the basis of investigating the percolation mechanism of polymer flooding at home and abroad, an effective viscosity model of polymer solution considering viscoelasticity and mechanical degradation effect is established. It is found that the viscoelastic and mechanical degradation effects of polymer solution occur only in the near well zone, and the shear thinning rheology of polymer solution is maintained in a wide range. Using fractal theory to study the influence of microfracture on percolation of polymer solution, the unsteady flow model of polymer flooding two-zone composite, three-zone composite and double-media two-zone composite seepage flow model based on fractal theory is established. Based on the bilinear flow analysis method, an unsteady flow model of polymer flooding in the complex reservoir of effective diversion vertical fracture wells is established. The model is solved by Stehfest numerical inversion method and finite difference method. The typical curve is drawn and the shape of the curve is analyzed. The evaluation indexes of polymer solution injection ability mainly include the injection index Hall curve and Hearn curve. These methods are similar to modern production dynamic analysis methods. The main purpose of this paper is to study the variation of polymer solution injection volume and pressure with time, and to obtain some physical parameters. Therefore, according to the unsteady flow model of polymer flooding and the introduction of material equilibrium time, four models of Agarwal-Gradnerian NPI and Transient injection ability were established, and the curve shape and parameter sensitivity were analyzed.
【学位授予单位】：中国石油大学(华东)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TE357.46

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