The associative polymer flooding: an experimental study

Abstract

This study investigates the sandpack displacement of low viscosity oil (1.68 cP) by brine and aqueous solutions of associative polymers. Polymer flooding has been thoroughly investigated in many laboratory and field tests. Polymer flooding is one of the most widely used enhanced oil recovery (EOR) methods. The method of polymer flooding is not used for development of oil fields with gas caps, fractured reservoirs, high permeability and active bottom-water drive. In the application of polymer flooding, coefficient of oil recovery is increased by 3-10%. Hydrolyzed polymers undergo the significant thermal and chemical degradation at high temperature and salinity. In recent years, researchers have turned their attention to associative polymers. An application of associative polymers to withstand degradation in high temperature and high salinity conditions can enhance oil recovery in high heterogeneous fields. This article presents the results of studies of oil displacement by associative polymers in a two-layer core model. In laboratory studies, the core selected from a sandy reservoir of the South Turgay Basin of the Republic of Kazakhstan was used. Solutions of the following polymers were studied: hydrolyzed polyacrylamide (HPAM) and associative polymer. The physicochemical conditions of the experiments corresponded to the reservoir conditions of the sand layer of the South Turgay Basin: temperature of 82 °C and the salinity of the brine 92,000 ppm. Experiments revealed that the associative polymer is more stable in simulated reservoir conditions than the HPAM polymer. Associative polymer flooding was recommended for pilot testing at the reservoir of the South Turgay Basin.

Perspective Review of Polymers as Additives in Water-Based Fracturing Fluids

“…Associative polymers are structured in a way that the backbone of the polymer is attached to both hydrophobic and hydrophilic moieties. 47 Molecules/intermolecular associations form an amphiphilic structure, thereby enhancing the fluid performance in high-salinity reservoirs.…”

“…Moreover, in the recent literature, interesting results were reported from hydrophobically modified polymers (associative polymers), which can offer a great tolerance at higher salinities. Associative polymers are structured in a way that the backbone of the polymer is attached to both hydrophobic and hydrophilic moieties . Molecules/intermolecular associations form an amphiphilic structure, thereby enhancing the fluid performance in high-salinity reservoirs.…”

Polymer viscosifier systems with potential application for enhanced oil recovery: a review

“…Similar studies were also performed by Zhang et al (2019), who noted that the injection of HMAP in porous media increased the oil recovery factor by 18.7% compared to PHPA injection. Abirov et al (2019) performed porous media tests with commercial PHPA and HMAP solutions simulating conditions of the Turgay Southern Basin reservoir in Kazakhstan, where severe salinity and temperature conditions prevail (92 000 ppm TDS and 82°C). They reported that the associative polymer was more stable and efficient in the simulated reservoir conditions and recommended its pilot scale application.…”

The Effect of Shear on the Properties of an Associated Polymer Solution for Oil Displacement

“…Associative polymers are hydrophilic macromolecular chains with hydrophobic groups, the content of which is generally 2–5 mol%. Hydrophobic groups on the molecular chain cooperate with the electrostatic repulsion and attraction of charged-ion groups to make macromolecular chains produce intramolecular or intermolecular associations, combine to form independent aggregates, and form various supramolecular spatial network structures [ 11 , 12 , 13 ]. After the “dynamic physical glue network structure” formed by hydrophobic association is destroyed by external forces, this structure reassociates and restores part of the spatial structure [ 14 , 15 ].…”