Chemical EOR

Arabian Journal of Geosciences, 2022

Polymer flooding is a promising enhanced oil recovery (EOR) technique; sweeping a reservoir with a dilute polymer solution can significantly improve the overall oil recovery. In this overview, polymeric materials for enhanced oil recovery are described in general terms, with specific emphasis on desirable characteristics for the application. Application-specific properties should be considered when selecting or developing polymers for enhanced oil recovery and should be carefully evaluated. Characterization techniques should be informed by current best practices; several are described herein. Evaluation of fundamental polymer properties (including polymer composition, microstructure, and molecular weight averages); resistance to shear/thermal/chemical degradation; and salinity/hardness compatibility are discussed. Finally, evaluation techniques to establish the polymer flooding performance of candidate EOR materials are described.

Energies

Viscosity losses and high degradation factors have a drastic impact over hydrolyzed polyacrylamides (HPAM) currently injected, impacting the oil recovery negatively. Previous studies have demonstrated that biopolymers are promising candidates in EOR applications due to high thermochemical stability in harsh environments. However, the dynamic behavior of a biopolymer as scleroglucan through sandstone under specific conditions for a heavy oil field with low salinity and high temperature has not yet been reported. This work presents the rock–fluid evaluation of the scleroglucan (SG at 935 mgL−1) and sulfonated polyacrylamide (ATBS at 2500 mgL−1) to enhance oil recovery in high-temperature for heavy oils (212 °F and total dissolved solid of 3800 mgL−1) in synthetic (0.5 Darcy) and representative rock samples (from 2 to 5 Darcy) for a study case of a Colombian heavy oilfield. Dynamic evaluation at reservoir conditions presents a scenario with stable injectivity after 53.6 PV with a minim...

Energy, 2014

Owing to the inefficiency of the conventional primary and secondary recovery methods to yield above 20e40% of the OOIP (original oil in place) as incremental oil, the need for EOR (Enhanced Oil Recovery) techniques to recover a higher proportion of the OOIP has become imperative. ASP (Alkaline/Surfactant/ Polymer) is one of such techniques that has proven successful due to its ability to improve displacement and sweep efficiency. Alkalineesurfactantepolymer (ASP) flooding is a combination process in which alkali, surfactant and polymer are injected at the same slug. Because of the synergy of these three components, ASP is widely practiced in both pilot and field operations with the objective of achieving optimum chemistry at large injection volumes for minimum cost. Despite its popularity as a potentially cost-effective chemical flooding method, it is not without its limitations. This paper therefore focuses on the reviews of the application of ASP flooding process in oil recovery in the petroleum industry and its limitations in maximizing oil recovery from onshore and offshore reservoirs. Also discussed are technical solutions to some of these challenges.

International Petroleum Technology Conference, 2015

Polymer flooding is one of the most attractive chemical EOR techniques for sandstone reservoirs however due to complex geological heterogeneity and harsh reservoir conditions its full potential has not been explored in carbonate reservoirs. The main reason behind this limitation is the inability of conventional EOR polymers like HPAM and Xanthan to withstand these conditions. Candidate polymers must provide the required rheology at minimal polymer concentration, be thermally and mechanically stable, and result in a manageable adsorption on the reservoir formation. A polymer screening study has been conducted on a series of polymers, to identify the most suitable candidate that can tolerate the harsh reservoir conditions. Initially, rheological measurements are conducted on a series of polymers followed by filterability, injectivity, static and dynamic adsorption, mechanical and thermal stability testing as a screening criterion for polymers in EOR operations. Amongst the tested poly...

Processes, 2020

Polymer flooding is a promising enhanced oil recovery (EOR) technique; sweeping a reservoir with a dilute polymer solution can significantly improve the overall oil recovery. In this overview, polymeric materials for enhanced oil recovery are described in general terms, with specific emphasis on desirable characteristics for the application. Application-specific properties should be considered when selecting or developing polymers for enhanced oil recovery and should be carefully evaluated. Characterization techniques should be informed by current best practices; several are described herein. Evaluation of fundamental polymer properties (including polymer composition, microstructure, and molecular weight averages); resistance to shear/thermal/chemical degradation; and salinity/hardness compatibility are discussed. Finally, evaluation techniques to establish the polymer flooding performance of candidate EOR materials are described.

Polymers

Polymers play a significant role in enhanced oil recovery (EOR) due to their viscoelastic properties and macromolecular structure. Herein, the mechanisms of the application of polymeric materials for enhanced oil recovery are elucidated. Subsequently, the polymer types used for EOR, namely synthetic polymers and natural polymers (biopolymers), and their properties are discussed. Moreover, the numerous applications for EOR such as polymer flooding, polymer foam flooding, alkali–polymer flooding, surfactant–polymer flooding, alkali–surfactant–polymer flooding, and polymeric nanofluid flooding are appraised and evaluated. Most of the polymers exhibit pseudoplastic behavior in the presence of shear forces. The biopolymers exhibit better salt tolerance and thermal stability but are susceptible to plugging and biodegradation. As for associative synthetic polyacrylamide, several complexities are involved in unlocking its full potential. Hence, hydrolyzed polyacrylamide remains the most cov...

Applied Microbiology and Biotechnology, 2017

With a rising population, the demand for energy has increased over the years. As per the projections, both fossil fuel and renewables will remain as major energy source (678 quadrillion BTU) till 2030 with fossil fuel contributing 78% of total energy consumption. Hence, attempts are continuously made to make fossil fuel production more sustainable and cheaper. From the past 40 years, polymer flooding has been carried out in marginal oil fields and have proved to be successful in many cases. The common expectation from polymer flooding is to obtain 50% ultimate recovery with 15 to 20% incremental recovery over secondary water flooding. Both naturally derived polymers like xanthan gum and synthetic polymers like partially hydrolyzed polyacrylamide (HPAM) have been used for this purpose. Earlier laboratory and field trials revealed that salinity and temperature are the major issues with the synthetic polymers that lead to polymer degradation and adsorption on the rock surface. Microbial degradation and concentration are major issues with naturally derived polymers leading to loss of viscosity and pore throat plugging. Earlier studies also revealed that polymer flooding is successful in the fields where oil viscosity is quite higher (up to 126 cp) than injection water due to improvement in mobility ratio during polymer flooding. The largest successful polymer flood was reported in China in 1990 where both synthetic and naturally derived polymers were used in nearly 20 projects. The implementation of these projects provides valuable suggestions for further improving the available processes in future. This paper examines the selection criteria of polymer, field characteristics that support polymer floods and recommendation to design a large producing polymer flooding.

2008

Polymer flooding has been applied for petroleum recovery and the main results of this method are the effective increasing in oil production and the reduction of water circulation The objective of this work is to present a methodology for pre-selecting a polymer to be used in future research on enhanced oil recovery (EOR) by injecting polymer solution. A reservoir was selected and characterized. Seven samples of commercial partially hydrolyzed polyacrylamide (PHPA) were also selected and characterized. Polymer solutions were prepared and characterized in terms of filterability , viscosity, stability (under reservoir conditions) and mechanical degradation. Polymer-reservoir interaction was also investigated. The results showed that it is very useful to establish a methodology to pre-select the more suitable polymer for fluid injection operations in oil field. Besides, for the conditions used in this study, the best polymer presents hydrolysis degree of 30%, molar mass of 5·10 6 g /mol...

Applied Microbiology and Biotechnology, 2021

With a rising population, the demand for energy has increased over the years. As per the projections, both fossil fuel and renewables will remain as major energy source (678 quadrillion BTU) till 2030 with fossil fuel contributing 78% of total energy consumption. Hence, attempts are continuously made to make fossil fuel production more sustainable and cheaper. From the past 40 years, polymer flooding has been carried out in marginal oil fields and have proved to be successful in many cases. The common expectation from polymer flooding is to obtain 50% ultimate recovery with 15 to 20% incremental recovery over secondary water flooding. Both naturally derived polymers like xanthan gum and synthetic polymers like partially hydrolyzed polyacrylamide (HPAM) have been used for this purpose. Earlier laboratory and field trials revealed that salinity and temperature are the major issues with the synthetic polymers that lead to polymer degradation and adsorption on the rock surface. Microbial degradation and concentration are major issues with naturally derived polymers leading to loss of viscosity and pore throat plugging. Earlier studies also revealed that polymer flooding is successful in the fields where oil viscosity is quite higher (up to 126 cp) than injection water due to improvement in mobility ratio during polymer flooding. The largest successful polymer flood was reported in China in 1990 where both synthetic and naturally derived polymers were used in nearly 20 projects. The implementation of these projects provides valuable suggestions for further improving the available processes in future. This paper examines the selection criteria of polymer, field characteristics that support polymer floods and recommendation to design a large producing polymer flooding.