Interception Characteristics and Pollution Mechanism of the Filter Medium in Polymer-Flooding Produced Water Filtration Process
Interception Characteristics and Pollution Mechanism of the Filter Medium in Polymer-Flooding Produced Water Filtration Process
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DOI：
10.3390/pr7120927
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发表时间：
2019-12
期刊：
影响因子：
3.5
通讯作者：
Xingwang Wang;Xu Xiaoxuan;D. Wei;Tang Zhiwei;Hu Changchao;B. Wei
中科院分区：
文献类型：
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作者：
Xingwang Wang;Xu Xiaoxuan;D. Wei;Tang Zhiwei;Hu Changchao;B. Wei
聚合物驱提高了原油采收率，但在应用该技术的过程中，也会产生大量含聚合物的采出水，对环境构成威胁。目前的加工主要集中在能否满足回注要求上。然而，许多工艺在现场实践中面临着净化效果、设施污染和经济合理性的挑战。为了充分了解油田滤池的结构和原理，基于几何相似和相似流动，利用自行设计的一套滤失模拟装置对含聚合物采出水的处理进行了研究，以满足中低渗透油藏的注水要求。结果表明，由于油田采出水中聚合物的存在，在滤料表面形成了稳定的胶体体系，降低了滤料对油滴和悬浮物的吸附。聚合物的存在也增加了水的粘度，促进了油污的乳化，增加了过滤分离的难度。随着过滤的进行，滤料床对聚合物的吸附达到饱和，滤后水中的聚合物和油污含量逐渐增加。悬浮物的浓度和颗粒大小最终超过过滤水质允许的标准，这主要是由于颗粒尺寸与滤料级配有关，以及聚合物和悬浮物在滤料表面的竞争吸附。过滤后的水的含油量也超过了允许的标准，聚合物取代了过滤介质孔隙和表面上的油滴。此外，生物质的悬浮颗粒由死亡细菌、菌丝和孢子组成，对油滴具有很强的附着和携带能力，导致过滤后水中的悬浮固体超标，油滴同时滞留在过滤出水中。
Polymer flooding enhances oil recovery, but during the application of this technology, it also creates a large amount of polymer-contained produced water that poses a threat to the environment. The current processing is mainly focused on being able to meet the re-injection requirements. However, many processes face the challenges of purifying effect, facilities pollution, and economical justification in the field practice. In the present work, to fully understand the structure and principle of the oil field filter tank, and based on geometric similarity and similar flow, a set of self-designed filtration simulation devices is used to study the treatment of polymer-contained produced water in order to facilitate the satisfaction of the water injection requirements for medium- and low-permeability reservoirs. The results show that, due to the existence of polymers in oil field produced water, a stable colloidal system is formed on the surface of the filter medium, which reduces the adsorption of oil droplets and suspended solids by the filter medium. The existence of the polymers also increases the viscosity of water, promotes the emulsification of oil pollution, and increases the difficulty of filtration and separation. As filtration progresses, the adsorption of the polymers by the filter medium bed reaches saturation, and the polymers and oil pollution contents in the filtered water increase gradually. The concentration and particle size of the suspended solids eventually exceed the permissible standards for filtered water quality; this is mainly due to the unreasonable size of the particle in relation to the filter medium gradation and the competitive adsorption between the polymers and the suspended solids on the surface of the filter medium. The oil concentration of the filtered water also exceeds the allowable standards and results from the polymers replace the oil droplets in the pores and on the surfaces of the filter medium. Moreover, the suspended particles of the biomass, composed of dead bacteria, hyphae, and spores, have strong attachment and carrying ability with respect to oil droplets, which cause the suspended solids in the filtered water to exceed the permissible standards and oil droplets to be retained in the filtered effluent at the same time.