Recovery Project Research Articles

Prediction of Key Parameters in the Design of CO2 Miscible Injection via the Application of Machine Learning Algorithms

The accurate determination of key parameters, including the CO2-hydrocarbon solubility ratio (Rs), interfacial tension (IFT), and minimum miscibility pressure (MMP), is vital for the success of CO2-enhanced oil recovery (CO2-EOR) projects. This study presents a robust machine learning framework that leverages deep neural networks (MLP-Adam), support vector regression (SVR-RBF) and extreme gradient boosting (XGBoost) algorithms to obtained accurate predictions of these critical parameters. The models are developed and validated using a comprehensive database compiled from previously published studies. Additionally, an in-depth analysis of various factors influencing the Rs, IFT, and MMP is conducted to enhance our understanding of their impacts. Compared to existing correlations and alternative machine learning models, our proposed framework not only exhibits lower calculation errors but also provides enhanced insights into the relationships among the influencing factors. The performance evaluation of the models using statistical indicators revealed impressive coefficients of determination of unseen data (0.9807 for dead oil solubility, 0.9835 for live oil solubility, 0.9931 for CO2-n-Alkane interfacial tension, and 0.9648 for minimum miscibility pressure). One notable advantage of our models is their ability to predict values while accommodating a wide range of inputs swiftly and accurately beyond the limitations of common correlations. The dataset employed in our study encompasses diverse data, spanning from heptane (C7) to eicosane (C20) in the IFT dataset, and MMP values ranging from 870 psi to 5500 psi, covering the entire application range of CO2-EOR. This innovative and robust approach presents a powerful tool for predicting crucial parameters in CO2-EOR projects, delivering superior accuracy, speed, and data diversity compared to those of the existing methods.

Associations between health-related behaviors and self-reported cognitive symptoms in U.S. military personnel injured on deployment

Health behaviors may be core contributors to cognition and mental health following mild traumatic brain injury (TBI). The aims of the present study examined: (1) whether health behaviors including sleep duration, alcohol use, and physical activity differed in injured military personnel with and without deployment-related mild TBI history and (2) the relative contributions of health behaviors and deployment-related mild TBI history to self-reported cognitive, posttraumatic stress disorder (PTSD), and depressive symptoms. Participants included 3076 military personnel injured on deployment participating in the Wounded Warrior Recovery Project, an ongoing web-based study. Military personnel with deployment-related mild TBI history reported similar rates of physical activity and levels of alcohol problems as those without, but were less likely to report receiving the recommended duration of sleep. When adjusting for demographic and injury variables, all three health behaviors were associated with cognitive, PTSD, and depressive symptoms. Alcohol problems demonstrated significant but small effects across all outcomes measures (ηp2=.01) whereas physical activity was associated with slightly larger effects albeit still within the small range (ηp2=.02-0.04). Duration of sleep bordered a medium effect for cognitive symptoms (ηp2=.05) and was in the medium range for PTSD and depressive symptoms (ηp2=.06). Although deployment-related mild TBI history was significant in all models, effect sizes were small (ηp2=.01). Findings from the present study provide support that health behaviors have stronger effects with regard to cognitive, PTSD, and depressive symptoms compared to deployment-related mild TBI history in military personnel and, given their modifiable nature, may represent treatment targets in this population.

Optimizing Modularization of Residential Housing Designs for Rapid Postdisaster Mass Production of Housing

Postdisaster housing reconstruction (PDHR) is a highly complex process because of the large number of recovery projects for affected communities and the shortage of resources after a disastrous event. PDHR also needs a strategy that reconsiders it as a large-scale integrated portfolio of projects instead of individual building reconstruction projects. However, this complexity and the lack of a holistic, systematic approach for planning frequently lead to an ad-hoc or case-by-case decision-making process. To resolve this critical challenge in postdisaster housing mass production, this study investigates and develops a systematic approach that optimizes the design modularization of housing recovery projects considering manufacturing, transportation, and assembly factors for a cost-efficient and sustainable implication of modular construction (MC) in PDHR. Using the genetic algorithm-based optimization method, the proposed method addresses the possible trade-offs between the commonality and suitability of the module configurations for PDHR projects. In addition, the authors used a set of feasible configurations of a variety of modular housing designs created from the AI-based generative design system and conducted the mass production scenarios after a disaster to validate the accuracy and robustness of the proposed methodology. The results clearly show that the proposed method significantly improved optimization and decision-making of MC design and construction processes and considerably enhanced rapid and logical responses to the demands of the postdisaster recovery process. The newly developed method is expected to assist the planners in formalizing the commonality concept in the PDHR process and achieving an optimal level of modularity and commonality that meet the required variation while maintaining the advantages of mass production.

Nanocomposite of binary colloids in effective CO2 utilization in porous media for enhanced oil production and wettability alteration

Carbon dioxide injection is a renowned enhanced oil recovery method, where the inclusion of a novel material is appreciated via mobility control of injected CO2 during flow through porous and permeable oil reservoirs. Therefore, the combination of nanoparticles and their associated additives is recommended for foam flooding schemes. Thus, this study reports the use of nanocomposites of SiO2 (0.1 – 2 wt%) and TiO2 (0.1 wt%) in promoting CO2 utilization in oil recovery projects. The assessment of a foam emulsion is a crucial and interesting task to understand the basic fundamental of three-phase interactions viz., Crude oil (oil phase), nanocomposites (aqueous phase), and CO2 (gas phase) in the context of foam-emulsion, and was examined via microscopic and rheological characterization. CO2 foam showed temperature tolerance capability and a shear-thinning viscoelastic nature due to the inclusion of nanocomposites. Furthermore, wettability alteration was understood via contact angle measurements between CO2 and nanocomposite. Interestingly, the contact angle was reduced to 39° after the inclusion of 0.1 wt% TiO2 and CO2 in the system. Finally, nanocomposite stabilized CO2 foam demonstrated a total cumulative oil recovery of 78 % at (40 °C), higher than the cumulative oil recovery (70 %) associated with nanocomposite without CO2. The results of this study suggest that CO2 utilization for oil recovery can be enhanced by developing its viscous foam, stabilized by a nanocomposite of SiO2 and TiO2 nanoparticles.

Experimental Investigation on the Relationship between Biot’s Coefficient and Hydrostatic Stress for Enhanced Oil Recovery Projects

The majority of global conventional oil reservoirs have been dramatically depleted during the last few decades. To increase the oil production rate, enhanced oil recovery (EOR) techniques are commonly utilized. The ratio of the recovered oil volume to the rock volume change is defined as Biot’s coefficient. During the EOR operations, Biot’s coefficient continuously changes due to the fluid injection and oil production; however, so far, only porosity-dependent or constant values of Biot’s coefficient have been incorporated in the EOR calculations, which is not valid since the role of external stress changes is overlooked. In this research, the Biot’s coefficient of a sandstone formation was measured through the acoustic wave propagation technique. A stress-dependent equation of Biot’s coefficient was achieved for application in the EOR calculations. The findings illustrated that Biot’s coefficient decreases logarithmically with the hydrostatic stress. Moreover, the Biot’s coefficient varied from 0.52 to 0.60 for an applied hydrostatic stress of 3.50 MPa to 21 MPa. Furthermore, it was found that there was no anisotropy of Biot’s coefficient in the sandstone formations. The extracted empirical correlation can be utilized for EOR projects in which the recovered oil volume is of paramount importance economically.

Управление проектами финансового оздоровления компаний

The article is devoted to preventive measures for the financial recovery of companies under a threat of bankruptcy. These measures are not regulated by legislation or are only partially regulated and, as a rule, are aimed at obtaining a unique result – the restoration of the company's activities. This makes it possible to use project management technologies. The study classifies companies that may need financial recovery projects, identifies restructuring procedures known in both developed and developing countries, shows the heterogeneity of financial recovery projects and their differences depending on various determinants. Special attention is paid to the specific features of such projects’ management: in particular, the existence of stabilization phase, the necessity of organizing successful negotiations and mediation during the implementation of projects, the development of other intangible components of the success of financial recovery projects along with the search for new financing, postponement of payments on old debts.

Estimating the Potential for Waste Heat Recovery in Italian Dairy Sector Using a Bottom-Up Approach and Data from Energy Audits

As a result of the expected increase in food demand, improving the sustainability of the food industry has become a priority worldwide. The recovery of industrial waste heat is widely regarded as a key strategy to reduce the energy consumption and greenhouse gas emissions of food manufacturing processes. Estimating the available recoverable waste heat can contribute to driving actions that promote the effective exploitation of such an untapped energy source. This study aimed to evaluate the waste heat potential of large and energy-intensive Italian dairy companies. To this end, a methodology that combined key transfer figures adapted to the Italian industrial context and data on fossil fuels consumption from energy audits was adopted to assess the technical waste heat potential. A comparison with the overall waste heat recovered from the projects proposed by large and energy-intensive dairy companies was carried out to estimate the residual waste heat available. Finally, the economic waste heat potential was assessed by varying the heat transfer operating conditions between the waste heat sources and sinks, and assuming that waste heat recovery was operated through heat exchanger technology. The technical waste heat potential of large and energy-intensive dairy industries was valued at roughly 75.6 GWht/year. Simulation results also showed that more than 90% of the studied companies exhibited payback periods below three years for all waste heat recovery projects, except for those involving gas-to-gas or gas-to-liquid heat transfers.

How, when, and to what degree do people with alcohol dependence recover their psychological wellbeing and quality of life? The Madrid Recovery Project.

The consensus on recovery from alcohol use disorder (AUD) has shifted toward encompassing psychological wellbeing and quality of life dimensions. However, few studies have explored the long-term recovery process and its dimensions, timing, styles, and modes. The aim of this study was to investigate the extent, timing, and process of psychological wellbeing and quality of life recovery in alcohol use disorder (AUD) patients, as well as the relationship with classic dimensions of AUD recovery. A cross-sectional study has been carried out with 348 participants with AUD, in different abstinence periods (1 month-28 years), and 171 control subjects. Participants underwent a psychological evaluation, which included self-informed measures of psychological wellbeing, quality of life, negative emotionality, and coping strategies related to alcohol consumption avoidance. Statistical analysis included linear and non-linear regression models between psychological dimensions and maintenance of abstinence, as well as matching the scores of the sample with AUD to those of controls. Scatter plots were used to explore inflection points. In addition, mean comparison tests were performed between participants with AUD and controls and by gender. In general, according to the regression models, there were pronounced increases in indices of wellbeing and coping strategies (and pronounced decreases in negative emotionality) during the first 5 years of abstinence, followed by less pronounced improvements. The matching of AUD subjects in wellbeing and negative emotionality indices with controls occurs at different times: (a) 1 year or less: physical health; (b) 1-4 years: psychological health; (c) 4-10 years: social relationships, wellbeing, and negative emotionality; and (d) more than 10 years: autonomy and self-acceptance. There are statistically significant differences by gender for the negative emotionality and physical health variables. Recovery from AUD is a long process that involves improvements in wellbeing and quality of life. Four stages can be described in this process, with the most pronounced changes occurring during the first 5 years of abstinence. However, AUD patients take more time to obtain similar scores to controls in several psychological dimensions.

Adsorption characteristics, isotherm, kinetics, and diffusion of nanoemulsion in tight sandstone reservoir

Nowadays, nanoemulsions have shown a high application potential in improving hydrocarbon recovery from tight reservoirs. However, the adsorption characteristics, isotherms, kinetics of nanoemulsions onto reservoir rocks surface and the diffusion behavior into reservoir matrix are still not been systematically clarified. In this work, nanoemulsion was prepared by diluted microemulsion method using two nonionic surfactants, isopropanol, limonene and 2.0 wt% KCl solution. The static adsorption capacity measurement under different influencing factors were carried out, and the adsorption process was characterized through equilibrium isotherms and kinetic studies. Also, the diffusion behavior of nanoemulsion in the sandstone reservoir matrix were evaluated by core flooding experiments. Results indicated that the nanoemulsion was successfully synthesized and the droplet size mainly distributed between 8 and 18 nm. It had been found that the optimal static adsorption experimental parameters for 0.1 wt% nanoemulsion were 1:8 solid–liquid ratio and 50/60 mesh rock powder. Equilibrium adsorption results indicated that Langmuir model yielded a better fit which means that single-layer coverage of the surfactants composed of nanoemulsion onto the rock surfaces was more probable. Meanwhile, it was concluded that the pseudo-second order model could better describe the kinetic behavior of nanoemulsion adsorption onto the rock surfaces, which revealed that the adsorption rate was positively correlated with the nanoemulsion concentration. Dynamic adsorption experiments showed that the adsorption amount is inversely proportional to the core permeability, while the diffusion coefficient increases with the increase of permeability. Moreover, the advantage of nanoemulsions over sole surfactant is that the oil nucleus in the nanoemulsions enable control the release of the attached surfactants, and there is a competitive adsorption relationship between oil nucleus and rock surface for the free surfactants in the solution, which offers a possibility for reducing the surfactant adsorption loss and extending the invasion distance in the reservoir matrix. The findings obtained in this study can help for better understanding of the interaction mechanism between nanoemulsions and reservoir rocks, and provide guidance for selecting appropriate nanoemulsions for the enhanced oil recovery (EOR) project in tight sandstone reservoirs.

Technology Focus: EOR Operations (June 2023)

While supply disruptions and price volatility are not new to the oil and gas industry, the dramatic drop in oil prices because of the COVID-19 pandemic severely affected global enhanced oil recovery (EOR) projects. To add fuel to the fire, the current geopolitical scenario leading to a surge in commodity prices and supply chain disruptions exacerbated this situation by negating any chances of recovery, at least in the short term. Concurrently, the rise in energy consumption and increasing demand for energy security worldwide warrants the need to increase global hydrocarbon production. However, rising environmental concerns with regard to greenhouse gas emissions, coupled with a decrease in the availability of easy-to-produce hydrocarbon resources, mandate the need for a gradual shift toward optimized recovery strategy in a sustainable and cost-efficient manner. As a result, current circumstances dictate focusing on low-cost and low-carbon EOR barrels to secure energy supply in the shorter term while continuing to develop innovative technologies and strategies for enhancing production in the longer term. Energy consumption for mature waterfloods increases sharply at higher water cuts primarily because of the recirculation of water through the existing swept pathways. Lower volumetric sweep in reservoirs leads to excessive water production and less oil recovery. To curb the menace of excess water production, conventional EOR techniques such as polymerflooding or in-depth conformance-control techniques are mostly implemented. Both methods have demonstrated cost savings because of reduced watercuts and reductions in CO2 generation by lowering reinjection of produced water. Additional costs of injectants, transport, and topside facilities, however, contribute to higher project costs. Early optimization measures for existing waterfloods using machine-learning (ML) approaches could enable optimal reservoir management and production by delineating reservoir heterogeneities more efficiently and predicting more-effective interwell connectivity. Furthermore, ML could contribute directly to the optimization and surveillance of EOR applications, which would subsequently affect the performance and the cost of such projects, thereby supporting the achievement of low-cost and low-carbon EOR barrels. Recommended additional reading at OnePetro: www.onepetro.org. SPE 214268 A Novel Approach To Combine Models To Evaluate Interwell Connectivity in a Waterflooded Reservoir With Limited Injection History by Yanfidra Djanuar, Dragon Oil, et al. SPE 210657 A Laboratory-to-Field Approach and Evaluation of Low-Salinity Waterflooding Process for High-Temperature/High-Pressure Carbonate Reservoirs by Hemanta Kumar Sarma, University of Calgary, et al. IPTC 22733 Like Cures Like Microbial Enhanced Oil Recovery in Biodegraded Crude by Thanapong Ketmalee, PTTEP, et al.

Digital Greenwood: Foregrounding Black Women Business Owners, Community Activism, and the Tulsa Race Massacre

Abstract: African American women helped make Historic Greenwood into the thriving community popularly known as “Black Wall Street.” Despite their rich and varied contributions as business owners and operators and church and community activists, their experiences are frequently ignored in historical and contemporary narratives. Women of Black Wall Street ( WBWS ), a digital humanities project released for the centennial commemoration in May 2021, reifies this by tracking and analyzing the social, intellectual, and economic contributions of Black women in Greenwood. Through this project, my student research team and I restore the visibility of Black women in the community, including writers like Mary Jones Parrish, who provided the first written account of the massacre, and Blanche M. Woodford, whose newspaper articles about Black Wall Street were read throughout the country. Using historical research and digital methods and tools, WBWS features contextual essays, biographies of ten Green-wood women, maps of their homes and businesses, and interviews with contemporary female business owners in the district. In this article, I discuss the site and the importance of bringing Historic Greenwood’s overlooked women online and to the public. I present how the project transforms the Black Wall Street story and joins digital recovery projects that bring forth the full humanity of marginalized people.

Building back better: Granular energy technologies in green recovery funding programs

Building back better: Granular energy technologies in green recovery funding programs

Fake news and fading views: A vanishing archive of the 1906 Atlanta race massacre

The absence, erasure, and exile of blackness from the archive breed a silence that has produced grounds for interrogation across numerous disciplines. The official record indexes the authority of the archive to shape what is available for view. Sites of remembrance such as memorials and historical markers are included in the vast material we engage for the sake of history, memory, and meaning. Such a site is the Five Points area of Atlanta, GA, where in 1906, a massacre of black Atlanteans bloodied the landscape and eluded significant remembrance. This article thinks alongside Saidiya Hartman’s project of recovery and Christina Sharpe’s practice of “wake work” to consider how writing with and against the archive through a blackened consciousness articulate alternative methods of engaging memory and care.

Electrical Tortuosity Index: A New Approach for Identifying Rock Typing to Enhance Reservoir Characterization Using Well-Log Data of Uncored Wells.

The world is gradually moving toward a severe energy crisis, with an ever-increasing demand for energy overstepping its supply. Therefore, the energy crisis in the world has shed important light on the need for enhanced oil recovery to provide an affordable energy supply. Inaccurate reservoir characterization may lead to the failure of enhanced oil recovery projects. Thus, the accurate establishment of reservoir characterization techniques is required to successfully plan and execute the enhanced oil recovery projects. The main objective of this research is to obtain an accurate approach that can be used to estimate rock types, flow zone indicators, permeability, tortuosity, and irreducible water saturation for uncored wells based on electrical rock properties that were obtained from only logging tools. The new technique is obtained by modifying the Resistivity Zone Index (RZI) equation that was presented by Shahat et al. by taking the tortuosity factor into consideration. When true formation resistivity (Rt) and inverse porosity (1/Φ) are correlated on a log-log scale, unit slope parallel straight lines are produced, where each line represents a distinct electrical flow unit (EFU). Each line's intercept with the y-axis at 1/Φ = 1 yields a unique parameter specified as the Electrical Tortuosity Index (ETI). The proposed approach was validated successfully by testing it on log data from 21 logged wells and comparing it to the Amaefule technique, which was applied to 1135 core samples taken from the same reservoir. Electrical Tortuosity Index (ETI) values show marked accuracy for representing reservoir compared with Flow Zone Indicator (FZI) values obtained by the Amaefule technique and Resistivity Zone Index (RZI) values obtained by the Shahat et al. technique, with correlation coefficients of determination (R2) values equal to 0.98 and 0.99, respectively. Hence, by using the new technique, the Flow Zone Indicator, permeability, tortuosity, and irreducible water saturation were estimated and then compared with the obtained results from the core analysis, which showed a great match with the R2-values of 0.98, 0.96, 0.98, and 0.99, respectively.

Hazardous Elements in Sediments Detected in Former Decommissioned Coal Mining Areas in Colombia: A Need for Environmental Recovery

This study demonstrates an investigation into nanomineralogical and geochemical evolution for the detection of hazardous elements from old, abandoned coal mining deposits capable of causing negative environmental impacts. The general objective of this study is to evaluate the number of nanoparticulate chemical elements in sediments collected during the years 2017 and 2022 from deactivated coal mining areas in the La Guajíra and Cesar regions of Colombia. Sediments were collected and analyzed from areas that experienced spontaneous coal combustion (SCC). The analysis consisted of traditional mineralogical analysis by X-ray diffraction and Raman spectroscopy, nanomineralogy by field emission scanning electron microscope-FE-SEM, and high-resolution transmission electron microscope-HR-TEM (energy dispersive X-ray microanalysis system-EDS). The analyzed sediment samples contained high proportions of amorphous materials containing the chemical elements As, Cl, Hg, Mo, Pb, Sb, and Se. This study emphasizes the need to implement environmental recovery projects at former, now abandoned coal extraction areas located in the investigated region, as they have negative effects on the environment and human health across large regions.

Consumer Views and Experiences of Secondary-Care Services Following REFOCUS-PULSAR Staff Recovery-Oriented Practices Training.

The use of recovery-oriented practice (ROP) can be challenging to implement in mental health services. This qualitative sub-study of the Principles Unite Local Services Assisting Recovery (PULSAR) project explored how consumers perceive their recovery following community mental health staff undertaking specific ROP training. Using a qualitative participatory methodology, 21 consumers (aged 18-63 years) participated in one-on-one interviews. A thematic analysis was applied. Four main themes were extracted: (1) connection, (2) supportive relationships, (3) a better life, and (4) barriers. Connections to community and professional staff were important to support consumers in their recovery journey. Many consumers were seeking and striving towards a better life that was personal and individual to each of them, and how they made meaning around the idea of a better life. Barriers to recovery primarily focused on a lack of choice. A minor theme of 'uncertainty' suggested that consumers struggled to identify what their recovered future might entail. Despite staff undertaking the ROP training, all participants struggled to identify language and aspects of recovery in their interaction with the service, suggesting a need for staff to promote open, collaborative conversations around recovery. A specifically targeted recovery resource might facilitate such conversation.

A new optimization method of energy consumption for dynamic boil-off gas

Related research on refrigerant optimization based on the dynamic BOG has yet to be proposed. This study offers a new dynamic optimization method for boil-off gas (BOG) re-liquefaction system to improve the system's energy efficiency. The performance of C3MR (the propane precooling mixed refrigerant cycle) is analyzed based on the steady state model of leading liquefaction equipment in the process simulation in Aspen HYSYS software. And the principle of the energy consumption variation law of propane precooled compressor and mixed refrigerant compressor, based on the actual possible disturbance range obtained in the natural gas liquefaction process, is applied to construct the multi-objective optimization model with minimum energy consumption and maximum heat exchanger efficiency. Finally, the dynamic responses of disturbances were achieved and discussed with the aid of GA (Genetic Algorithm) and PSO (particle swarm optimization). The optimized performance of the dynamic liquefaction cycle is 34.8% better than the steady condition system in terms of energy efficiency, and the maximum energy consumption can be reduced by 50.60%. The advantage of the proposed optimization framework is its adaptability to other dynamic liquefaction processes. It has practical reference significance for the cost control of the BOG re-liquefaction recovery project.

Designing and Evaluating Opioid Misuse Prevention Training for Rural Communities and Health Care Providers.

Through Substance Abuse and Mental Health Services Administration funding, Michigan State University (MSU) Extension partnered with MSU's Family Medicine and Health Department of Northwest Michigan to implement trainings for community members and health care providers to increase awareness and improve prevention efforts addressing opioid use disorder (OUD) in rural areas. We formed the Michigan Substance Use Prevention, Education and Recovery (MiSUPER) project to design and evaluate opioid misuse prevention trainings. A socio-ecological prevention model was an underlying conceptual framework for this project and drove strategies used in trainings, products created, and measurement. The purpose of this study is to determine the effectiveness of one-time online educational training events for rural community members and health care providers on community OUD issues, treatment options, and supports for those in recovery. Between 2020 and 2022, rural participants completed pre- and posttraining, and 30-day follow-up evaluation surveys. We report the demographic characteristics of community (n = 451) and provider (n = 59) participants, self-reported knowledge gained, and overall perceptions of the trainings. Findings show community members' knowledge increased from pre- to posttraining (p < .001) and was maintained at 3 months, while providers' knowledge was unchanged over time. Posttraining, community participants felt more comfortable speaking about addiction with family and friends (p < .001), and providers had better knowledge of local resources for patients who could not afford opioid misuse treatments (p < .05). All participants reported gaining knowledge of community resources for opioid misuse prevention, treatment, and recovery (p < .01). Opioid misuse prevention trainings may be most effective when adapted to leverage local resources.

Storing carbon dioxide for climate's sake: contradictions and parallels with enhanced oil recovery

An increase in carbon capture and storage (CCS) projects, including bioenergy with CCS (BECCS), has led to an urgent demand for storage sites, and Norway stands out for its ongoing and planned geological storage sites in a European context. Even though there are no commercial carbon dioxide enhanced oil recovery (CO2-EOR) projects in Norway and the North Sea, there is scientific literature linking CO2-EOR and CCS in this geographical region. CO2-EOR utilizes CO2 to extract additional oil, counteracting the climate change mitigation purpose of geological storage. This review article explores how CCS is represented in the scientific literature on CO2-EOR in the North Sea and Norway, with a focus on system synergies and contradictions in relation to climate change mitigation. The main themes in the scientific literature on CO2-EOR in the North Sea are climate change, economics, and geological feasibility. Monitoring, safety, and leakage in addition to transportation of CO2 are less salient. The results show that there are contrasting framings in the literature. One framing is that CO2-EOR is a gateway to large-scale storage which maintains, or even expands, the extraction of fossil fuels and contributes to a sustainable transition in the long run through knowledge building and shared infrastructure. In contrast, another framing is that CO2-EOR combined with CCS have goal conflicts and are therefore not compatible, illustrating complexities with geological storage. Finally, this study reflects on how techno-economic research on CO2 storage in the North Sea and Norway is furthered through critical social science perspectives.

Experimental Study on EOR in Shale Oil Cores during Associated Gasflooding: A Case Study from Yanchang Formation, Ordos Basin

Summary A significant amount of associated gas has been produced from shale oil reservoirs in the Ordos Basin, northern China, in recent years, which has provided an opportunity for using low-cost, associated gas in enhanced oil recovery (EOR) projects. However, there are few other reports of EOR projects in shale oil reservoirs using associated gas, and a quantitative evaluation of the technique is needed. Therefore, we conducted associated gas and waterflooding experiments in shale oil samples at constant and gradually increasing injection pressure while monitoring the spatial distribution of movable and residual oil by means of nuclear magnetic resonance (NMR) technology. Before the injection experiments, we performed mercury intrusion tests and measured the NMR transverse relaxation time, T2, of fully saturated samples to characterize the pore-throat size distribution of rock samples. Furthermore, we established a novel and robust mathematical model based on a fractal description of the pore space and a capillary tube model to determine the lower limit of the pore radius of movable oil, rc, during gas- and waterflooding. We observed that the oil recovery factor at a low injection pressure (i.e., 0.6 MPa) during the associated gasflooding was lower than that during waterflooding under both constant pressure injection mode and gradually increasing pressure injection mode. However, the performance of associated gasflooding was greatly improved by increasing the injection pressure. High injection pressure indeed produced a higher oil recovery factor, thinner residual oil film thickness, and smaller rc during associated gasflooding than during waterflooding under both injection modes. These differences in behavior appear to be linked to dissimilarities in flooding mechanisms at high and low injection pressures. Our main conclusion is that associated gasflooding at high injection pressure (i.e., 6 MPa) has a better potential for enhancing the oil recovery factor than waterflooding in shale oil reservoirs.