海上低渗高温气藏水平井解堵工艺研究

发布时间：2018-11-28 10:25

【摘要】：C气藏主力层系为低渗储层,目标层位温度较高,普遍采用水平井开发,部分井在出现投产后产量小甚至没有产量的情况。该区块所采用的“打孔管+射孔”的完井方式以及海上特殊施工环境的限制,对增产技术提出了特殊的要求,之前所进行的解堵增产措施针对性不足、效果不佳。本文在前人基础上,综合考虑储层状况、井身条件、产能需要和设备能力等问题,开展海上低渗高温气藏水平井解堵工艺研究。通过调研现场资料及对取心井岩芯进行X射线衍射,明确了目标层位物性差、孔渗小、非均质性严重；通过开展室内敏感性评价实验,明确了目标层位为弱～中偏弱速敏、中偏弱水敏、弱土酸酸敏、弱碱敏。通过对目标水平井钻完井伤害模拟及生产过程中产生的潜在伤害因素分析,明确了工程因素对储层的伤害,揭示了井层条件下对解堵工艺和解堵液体系的特殊需求。通过大量实验评价优选,确定复合解堵工作液配方。与该气藏以往使用的解堵液相比,此配方包括复合破胶液、非酸及酸化解堵液。通过对储层伤害原因和储层改造面临的难点分析和评价,针对C气藏储层伤害的主控因素,基于海上解堵工艺的可行性,以及经济效益考虑,确定采取“多级复合解堵工艺”。开展水平井井筒及浅表解堵工艺方案研究,优选复合破胶液体系以及非酸解堵液体系,通过物理冲刷和化学破胶双重作用解除近井地带浅表的固相及液相侵入等综合堵塞。以目标储层单井典型管柱结构建立三维模型,利用F1uent软件对解堵工作液在水平井段的流场进行模拟,研究了影响流场速度分布的因素和影响规律,明确了不同施工参数及打孔管柱规格下的近井壁处的流速分布规律,判断解堵工作液清洗效果,优化工艺参数。开展水平井深度酸化工艺研究方案研究,对缓速酸酸液体系进行优选。实验结果表明该体系能够满足缓速、防膨、缓蚀等性能要求,对储层渗透率改善明显。对酸化施工关键参数进行了优化设计,包括最大施工排量、极限泵压、酸化工作液用量以及返排措施等。本文从理论研究、室内实验和数值模拟等方面研究,得到了一套针对C气藏的低渗高温气藏水平井的复合解堵技术,对该区块的解堵增产具有重要的指导意义。
[Abstract]:The main formation system of C gas reservoir is low permeability reservoir and the temperature of target horizon is high. Horizontal wells are widely used for development. Some wells have little or no production after they are put into production. The completion mode of "perforating pipe" adopted in this block and the limitation of special offshore operation environment have put forward special requirements for the production increasing technology. The previous measures for removing plugging and increasing production are insufficient in pertinence and poor in effect. In this paper, based on the former, considering the reservoir conditions, wellbore conditions, productivity needs and equipment capacity, research on the plugging removal technology of horizontal wells in low permeability and high temperature gas reservoirs is carried out. By investigating the field data and conducting X-ray diffraction on the core of the coring well, it is clear that the physical property of the target horizon is poor, the porosity and permeability are small, and the heterogeneity is serious. Through the laboratory sensitivity evaluation experiments, it is clear that the target horizon is weak to moderate weak speed sensitivity, middle weak water sensitivity, weak soil acid sensitivity and weak base sensitivity. Through the simulation of drilling and completion damage in the target horizontal well and the analysis of the potential damage factors in the production process, the damage caused by engineering factors to the reservoir is clarified, and the special requirements of the plugging removal process and the fluid plugging system under the conditions of the well layer are revealed. Through a large number of experiments to evaluate the optimal selection, the formula of compound plugging solution was determined. Compared with the gas reservoir used in the past, this formula includes compound gel breaking solution, non acid solution and acid solution. Based on the analysis and evaluation of the causes of reservoir damage and the difficulties encountered in reservoir reconstruction, and in view of the main controlling factors of reservoir damage in C gas reservoir, based on the feasibility of offshore plugging removal technology and the consideration of economic benefits, the "multistage composite plugging removal process" is determined. This paper studies the plugging removal technology of horizontal well bore and shallow surface, optimizes the compound gel breaking liquid system and the non-acid plugging system, and solves the comprehensive blockage of the shallow surface solid and liquid phase invasion in the near well area by the dual action of physical scouring and chemical gel breaking. Based on the typical pipe string structure of a single well in the target reservoir, a three-dimensional model is established, and the flow field of the plugging solution in the horizontal well is simulated by using F1uent software. The factors affecting the velocity distribution of the flow field and the influencing law are studied. The distribution law of velocity near the shaft wall under different construction parameters and perforating pipe string specifications is defined, the cleaning effect of the working fluid for plugging removal is judged, and the technological parameters are optimized. The deep acidizing process of horizontal well was studied and the acid solution system was selected. The experimental results show that the system can meet the performance requirements of retarding, anti-swelling and corrosion inhibition, and can obviously improve the reservoir permeability. The key parameters of acidizing construction are optimized, including the maximum construction displacement, the limit pump pressure, the amount of acidizing working fluid and the measures of backflow, etc. In this paper, from the aspects of theoretical research, laboratory experiments and numerical simulation, a set of complex plugging removal techniques for horizontal wells of low permeability and high temperature gas reservoirs in C gas reservoir are obtained, which is of important guiding significance for removing plugging and increasing production in this block.
【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】：TE37

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