Interception Characteristics and Pollution Mechanism of the Filter Medium in Polymer-Flooding Produced Water Filtration Process

Abstract

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.

Technologist in Residence for Advanced Manufacturing and Materials in Unconventional Oil and Gas Equipment and Infrastructure

“…In order to satisfy both options, it is common to use two endpoint symbols in models of two-phase relative permeability. The endpoints / endpoint parameters for the relative permeabilities of oil and water are: 1) the permeability for oil relative to that at irreducible (minimal) water saturation K row (S wir ) = K rot (20) and 2) the relative permeability for water relative to that of water with residual (minimal) oil saturation after water flooding K rw (S wor ) = K rwr (21) These symbols have merits and limitations. Use of the symbol K rot emphasizes that it represents the maximum (top) point of K row .…”

“…There are many studies of how to mitigate the interference of these additives in desalination, for instance the removal of polyacrylaminde from water produced during polymer flooding. 21…”

Experimental Study on Polymer flooding-assisted CO2-based Cyclic Solvent Injection Process for Enhancing Oil Recovery in Heavy Oil Reservoirs

“…There are some limitations regarding the steamassisted gravity method, chemical flooding, and in-situ combustion method, such as huge energy consumption [6] and greenhouse gas emissions [13] during SAGD process, environment pollution potential during chemical flooding process [14,15] and high risk due to lose control during ISC process [9,10,16]. The CSI process involves circulating a specific solvent into the reservoir to displace the oil and improve the recovery factor [3].…”

“…Among the previous proposed researches in improving the performance of the CSI process, polymer has not been introduced into the CO2-based CSI process. Polymer flooding is famous for its excellent ability to increase viscosity and reduce relative permeability of displacing phase, further enlarge swept area and enhancing oil recovery factor [15,[44][45][46]. Thus, polymer flooding has been applied for the reservoir development for the past several decades.…”

Recycling of Waste Oils: Technology and Application

“…The exploitation of the oil produced from pyrolysis of plastic wastes [3]. • Some recent advances in polymer flooding technique for the enhanced oil recovery [4].…”