Key aspects of polymeric nanofluids as a new enhanced oil recovery approach: A comprehensive review

Experimental and theoretical investigation of cationic-based fluorescent-tagged polyacrylate copolymers for improving oil recovery

The growing need for energy and the depletion of oil wells necessitate advanced Enhanced Oil Recovery (EOR) techniques, particularly water and polymer flooding, which play a crucial role in augmenting hydrocarbon recovery rates. However, water flooding in high-permeability layers often leads to water breakthroughs, reduced sweep efficiency, and the formation of preferential channels, posing significant challenges to oil recovery and reservoir management. Conformance control treatments, including the use of polymer microspheres, offer a promising solution by sealing high-permeability zones and enhancing sweep efficiency. This study focuses on the application of fluorescent polymer microspheres based on polyacrylamide, which is extensively employed in the oil sector as an oil displacement agent. Fluorescent polymers called Poly 400, Poly 200, and Poly 600, incorporating cationic methacrylamide monomers, were synthesized through copolymerization to create amphiphilic polymers with enhanced stability and functionality. These fluorescent polymers were evaluated through flooding tests using a quarter-five-spot model of transparent quartz glass under UV light, allowing for instantaneous measurement and observation of fluorescence intensity. At reservoir conditions, the oil displacement experiments confirm that the incremental oil after water flooding by Poly 400, Poly 200, and Poly 600, is 13.1%, 9.1%, and 6.1% of OOIP respectively. The findings showed that fluorescent polymer microspheres could efficiently target high-permeability layers, adapt to varying pore throat sizes, and improve the plugging rate of high-permeability channels, thereby optimizing oil recovery. A subsequent simulation study using the CMG simulator provided further insights into the efficacy of these fluorescent polymers as EOR agents, revealing their potential to enhance sweep efficiency and enhance oil recovery. Simulation results showed that oil saturation decreased from 68% (initial) to 13.5%, 16.1%, and 18.3% after Poly 400, Poly 200, and Poly 600 flooding respectively. This work highlights the potential of fluorescent polymer microspheres as a valuable tool for EOR applications, offering significant advancements in reservoir management and oil recovery optimization.

Comprehensive review of enhanced oil recovery strategies for heavy oil and bitumen reservoirs in various countries: Global perspectives, challenges, and solutions

This study presents a comprehensive review of enhanced oil recovery (EOR) methods tailored specifically for high permeable heavy oil/bitumen (HOB) reservoirs, encompassing reservoir properties, production techniques, and associated challenges. In contrast to existing literature, this research uses a novel approach by delving into the production history and methodologies employed in prominent HOB-producing countries. As a result, some comprehensive primary reservoir threshold criteria are created via coupling the presented information in various literatures. Also, the analysis reveals diverse global strategies for HOB production. Canada's majority of HOB reservoirs, with average gravity less than 11 API, employ surface mining and cold production with sand. Russia's higher gravity HOB reservoirs face challenges with combustion methods. Venezuela emphasizes multilateral horizontal wells and EOR methods like down-hole electrical heaters, surfactant injection and thermal methods. In the USA, a novel downhole steam generation method shows promise. Argentina focuses on Centenario formation production with steam injection and polymer/gel treatment after water flooding, while China utilizes cyclic steam stimulation (CSS), Fire flooding and integrated technologies after water flooding. Oman's Marmul field uses polymer and alkaline-surfactant-polymer flooding for water-cut reduction while Sudan employs infill horizontal wells, deeper re-completion, cement squeezing, partially perforating for the same purpose. As a final conclusion, surface mining is prevalent for low-depth bitumen reservoirs, whereas cold methods are preferred during the early stages of heavy oil production. Furthermore, among the EOR methods, CSS has the biggest share in oil production specially in Colombia (Middle Magdalena basin), Canada (Athabasca field) and China. These findings underscore the importance of tailoring extraction methods to the unique characteristics of each HOB reservoir for optimal production efficiency. By leveraging insights from global production histories and innovative techniques, substantial improvements in oil recovery and operational efficiency can be achieved, paving the way for sustainable utilization of this vital energy resource.

Assessment of modified chitosan composite in acidic reservoirs through pilot and field-scale simulation studies

Chemical flooding through biopolymers acquires higher attention, especially in acidic reservoirs. This research focuses on the application of biopolymers in chemical flooding for enhanced oil recovery in acidic reservoirs, with a particular emphasis on modified chitosan. The modification process involved combining chitosan with vinyl/silane monomers via emulsion polymerization, followed by an assessment of its rheological behavior under simulated reservoir conditions, including salinity, temperature, pressure, and medium pH. Laboratory-scale flooding experiments were carried out using both the original and modified chitosan at conditions of 2200 psi, 135,000 ppm salinity, and 196° temperature. The study evaluated the impact of pressure on the rheological properties of both chitosan forms, finding that the modified composite was better suited to acidic environments, showing enhanced resistance to pressure effects with a significant increase in viscosity and an 11% improvement in oil recovery over the 5% achieved with the unmodified chitosan. Advanced modeling and simulation techniques, particularly using the tNavigator Simulator on the Bahariya formations in the Western Desert, were employed to further understand the polymer solution dynamics in reservoir contexts and to predict key petroleum engineering metrics. The simulation results underscored the effectiveness of the chitosan composite in increasing oil recovery rates, with the composite outperforming both its native counterpart and traditional water flooding, achieving a recovery factor of 48%, compared to 39% and 37% for native chitosan and water flooding, thereby demonstrating the potential benefits of chitosan composites in enhancing oil recovery operations.