复合压裂液体系提高致密油藏渗吸采收率实验研究

发布时间：2019-03-23 17:14

【摘要】：近年来,随着压裂液技术的发展与完善,胍尔胶、合成聚合物、表面活性剂等各种压裂液技术基本成熟,并在特定储层需求的情况下得到应用。压裂液主体技术多元化对致密油藏的适应性以及实现回收再利用是未来一段时期满足压裂液技术需求和控制成本的决定因素,满足低伤害、低成本、高效环保等技术指标仍是未来压裂液发展方向,并对复合压裂液技术条件提出新见解;对复合压裂液技术提出新思路;通过实验研究不断完善表活剂和新型压裂液的性能测定。通过对表面活性剂、复合压裂液体系性能评价,筛选出可提高致密油藏采收率的复合压裂液体系,并对其储层适应性进行分析。明确致密油藏复合压力液提高采收率机理及主要影响因素。亲水岩心饱和油过程存在门限压力,能自发渗吸驱油;亲油岩心中,油相可自吸,饱和过程中不存在门限压力;亲油岩心,在表面活性剂溶液中发生自发渗吸驱油,表面活性剂改善了亲油岩心的渗吸条件,润湿性发生变化,渗吸过程中湿相饱和度逐渐增加,湿相与非湿相的压力差也逐渐减小;毛管力逐渐与重力平衡;毛管力所引起的油水渗流可分为3个部分:水饱和度变化所引起的渗流,渗透率变化引起的渗流和润湿性变化引起的渗流;发生逆向渗吸的有利条件是亲水,低渗。自发渗吸驱油是裂缝油藏的重要采油机理,实验系统地研究了致密油藏中的渗吸作用、基质岩块之间的油水置换机理通过评价表面活性剂对基质岩块的渗吸能力改善作用,对改善致密油藏渗吸的方法与技术形成理性认识,为以毛管渗吸作用为基础的油藏开发方式提供依据。改善致密油藏的渗吸效果不应该一味地追求超低的界面张力为目的,降低界面张力对基质岩石渗吸驱油具有两面性的影响。
[Abstract]:In recent years, with the development and perfection of fracturing fluid technology, guanidine gel, synthetic polymers, surfactants and other fracturing fluid technologies have been basically mature and applied in the case of specific reservoir requirements. The adaptability of the main technology of fracturing fluid to tight reservoir and the recovery and reuse of fracturing fluid are the decisive factors to meet the technical demand and control cost of fracturing fluid in the future, and meet the requirements of low damage and low cost. The technical indexes such as high efficiency and environmental protection are still the developing direction of the fracturing fluid in the future, and some new opinions on the technical conditions of the composite fracturing fluid are put forward. This paper puts forward a new idea on the technology of composite fracturing fluid, and improves the performance determination of surface active agent and new fracturing fluid through experimental research. Through the performance evaluation of surfactant and composite fracturing fluid system, the composite fracturing fluid system which can improve the recovery of tight reservoir is selected, and its reservoir adaptability is analyzed. The mechanism and main influencing factors of improving oil recovery by composite pressure fluid in tight reservoir are clarified. In the core saturation process of hydrophilic rocks, there is threshold pressure, which can absorb and drive oil spontaneously, the oil phase can be self-primed in the core of the hydrophilic rock, and there is no threshold pressure in the process of saturation. In the oil-friendly core, spontaneous imbibition and flooding occur in surfactant solution, surfactant improves the percolation condition of oil-friendly core, wettability changes, and the saturation of wet phase increases gradually in the process of imbibition. The pressure difference between wet phase and non-wet phase also decreases gradually. The oil-water seepage caused by capillary force can be divided into three parts: the seepage caused by the change of water saturation, the seepage caused by the change of permeability and the seepage caused by the change of wettability. The advantage of reverse imbibition is hydrophilicity and low permeability. Spontaneous permeability flooding is an important oil recovery mechanism in fractured reservoirs. The imbibition in tight reservoirs is systematically studied. The oil-water displacement mechanism between matrix blocks is evaluated by evaluating the role of surfactant in improving the imbibition ability of matrix rock blocks. A rational understanding of the methods and techniques for improving the permeability of tight reservoirs is given, which provides a basis for the development of reservoirs based on capillary imbibition. In order to improve the permeability of tight reservoirs, ultra-low interfacial tension should not be pursued blindly, and the reduction of interfacial tension has dual effects on the permeability and displacement of matrix rock.
【学位授予单位】：东北石油大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TE357

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