bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Investigations of Caprock Integrity for Geological Carbon Storage Using Three-Dimensional Digital Image Correlation
Authors: Nath F. , Cabezudo E. , Romero N. G. 
Published: April 2024

Abstract
Caprock integrity is a critical concern in the successful implementation of geologic carbon capture and storage (CCS) projects. Caprock can break mechanically by radial cracking, plastic deformation, inner and outer debonding, and channelling. Understanding these failure mechanisms is crucial for designing robust management strategies in CCS applications. The classical approach is limited, so this study uses three-dimensional digital image correlation (3D-DIC) to study caprock sample deformation and failure for carbon capture and storage (CCS) reservoir to ensure caprock integrity.
Caprock samples from CCS reservoirs were put through diametrical compression using a precise 100 kN electro-mechanical load frame that moved at a rate of 0.05mm/min. The samples had a wide range of minerals. During the diametrical compression tests, a 3D-DIC image capture system was set up to watch the samples without touching them at a rate of 5 frames per second. A black-and-white speckle pattern is affixed to the specimen to monitor its deformation underload. The 3D-DIC system is used for image processing, visualization, and analysis of the caprock sample damage process under various load circumstances.
The study uses DIC-generated strain maps to analyze the process of caprock samples breaking, revealing a tension-compression ratio between 2% and 5%. The damage evolution process is divided into four stages: initial, linear elastic, elastic-plastic, and plastic damage. The results show that shale damage changes over time when samples have anisotropy and distinct heterogeneity, potentially causing caprock integrity issues.
This study focuses on predicting damage processes in caprock integrity in CCS using various methods. 3D-DIC outperforms these methods in terms of test range, affordability, accuracy, and field monitoring. This image-based algorithm is better at understanding anisotropic and heterogeneous conditions. The results will enhance the effectiveness of examining caprock integrity in CCS outperforms other methods in terms of test range, affordability, accuracy, and field monitoring.
Numerical Investigation of Hydrogen Storage Loss in Saline Aquifers
Authors: Khanal A. , Khan M. I. , Shahriar M. F. 
Published: April 2024

Abstract
Underground hydrogen storage (UHS), a large-scale and long-term energy storage system, can augment decarbonization prospects and drive the renewable energy sector forward due to the attractive energy capacity and environmentally friendly features of hydrogen (H2). One of the primary concerns of UHS is the in-situ loss of the injected H2 via different rock-fluid interactions. This study uses numerical simulation models to investigate the loss of H2 associated with the effects of different rock-fluid interactions and mass transfer mechanisms. Sensitivity studies were conducted to understand the impact of various factors, including the relative permeability hysteresis, capillary pressure, dissolution, and diffusion of H2 in brine. Furthermore, we also evaluated the effect of uncertainty in capillary pressure curves on trapped H2 using the parameters generated from an extensive literature survey. Finally, we compared the reservoir behavior in a finite and infinite-acting reservoir. The results showed that almost 20% of the injected H2 gets trapped in the reservoir due to the impact of the relative permeability at variable brine saturations. Furthermore, the results demonstrated that the relative permeability hysteresis during the imbibition phase significantly reduces the recoverable H2 due to residual trapping. Additionally, capillary pressure and dissolution moderately impacted the amount of trapped H2 during UHS. However, diffusion showed negligible impact on the final amount of H2 produced from the reservoir. The H2 loss in an infinite reservoir was significantly higher compared to the finite reservoir. To summarize, by analyzing the different H2-Rock-Fluid interactions, this study provides novel insights into the flow behavior of H2 in subsurface porous media.
Technical Assessment of Temporary Gas Storage to Avoid Flaring: A Case Study
Authors: Aoun Ala Eddine , Tomomewo Olusegun , Ameur Mohamed Cherif Ben , Masadeh Mohammad , Khetib Youcef 
Published: April 2024

Abstract
Environmental performance is a significant driver of energy production today, and providing attractive methods to reduce flaring remains a high priority for oil producers. Oil production from the Bakken and Three Forks formations has significantly increased over the last ten years without commensurate augmentation of gas capture infrastructure. This has resulted in the gas gathering network and treatment facilities operating at maximum capacity, leaving the system vulnerable during maintenance or operational emergencies. This study investigates the potential solution to mitigate flaring in case of temporary gas plant shutdown. The project’s main objective is to evaluate technically the feasibility of gas re-injection in the Bakken formation as a means to temporary store gas, increase oil recovery, reduce flaring and maintain compliance.
A flow simulation model was created and history matched to investigate continuous gas injection of a four-well pad. Different gas injection schemes were examined to identify the best scenario for temporary gas storage, assess the incremental production, analyze the effect on offset wells, evaluate gas recovery and efficiency. Gas reinjection has the added benefit of producing incremental oil that can offset installation and operational costs associated with gas compression and nonproducing time for a well during injection.
Results indicate that gas injection rate of 2.8 MMcfd has the highest gas injection efficiency, up to 0.3 bbl of oil equivalent per Mcf of gas injected. In addition, the increase in the gas production rate during injection phase is manageable, less than 0.7MMcfd. High gas injection rates yielded better gas recovery up to 80%, however lower gas injection efficiency and early gas breakthrough are expected. Low gas injection rates could produce incremental oil with moderate impact on offset wells. Communication of gas is likely to occur between wells within 1500 feet and wells positioned heel to heel that are common to the well-pad facility. The most promising injection scheme appeared to be dedicated injection of 2.8 MMcfd.
The findings support continued work to further investigate well configurations that can best benefit from the technique and to mature economic case studies.
This study is an important initiative aimed at addressing environmental concerns related to oil production in the Bakken and Three Forks formations. Gas re-injection is being explored as a viable solution to reduce flaring, increase oil recovery, and ensure compliance with environmental regulations. It represents a proactive approach by the oil industry to mitigate its environmental impact and optimize resource utilization.
A Novel Approach to Foam Characterization Using Multi-Frequency Dielectric Technique for Enhanced Oil Recovery
Authors: Bashir Ahmed , Hassan Amjed , Attia Hussein , Patil Shirish , Kamal Muhammad Shahzad , El-Husseiny Ammar , Mahmoud Mohamed 
Published: April 2024

Abstract
Foam has been used for controlling gas mobility during oil displacement processes in subsurface porous media to mitigate the negative impacts of low gas viscosity, reservoir heterogeneity, and gravity override. Therefore, one potential application of foam is in enhanced oil recovery (EOR) and CO2 sequestration. However, foams are thermodynamically unstable, and the stability properties need to be evaluated initially before introducing foam into the formations. In this study, we developed a novel approach to characterize foam using a multi-frequency dielectric technique.
The dielectric (DI) properties were used to evaluate the foam stability across various surfactant (sodium dodecyl sulfate (SDS)) concentrations (0.1 and 0.3 wt.%) in deionized water (DW) and seawater (SW) using Keysight impedance analyzer. The relative permittivity and electrical conductivity profiles are measured for the foam bulk at a frequency range of 1 MHz to 3 GHz using an open-ended coaxial probe. In parallel, a conventional test is used to study the foam stability over these same ranges of surfactant concentrations, and seawater concentrations.
The results confirmed that DI properties measurements provided insights into the foam's bulk properties and interactions. Moreover, the study revealed that water's conductivity increases with frequency due to ion polarization, particularly in the low to intermediate frequency range. When examining different concentrations of foam generated with SDS surfactant in deionized water, it was found that foam exhibited lower permittivity compared to pure deionized water. This is attributed to the interference of surfactant molecules with water's electric field interaction. Furthermore, deionized water demonstrated higher conductivity than foam, which contained more air bubbles, creating discontinuities in the conductive path. As the concentration of SDS increased, a slight increase in conductivity was observed, correlating with increased foam stability.
Additionally, the results demonstrated that dielectric properties could effectively evaluate foam stability, showing consistent results with foam stability observed through height measurement over time. This research suggests that dielectric properties could provide an efficient method for assessing foam stability across various foam compositions. Therefore, this will help to improve the understanding of foam stability and set a new standard for in-depth foam research in the petroleum industry, especially for EOR and CO2 sequestrations.
Application of Streamlines in Natural Depletion Systems
Authors: Tovar R. 
Published: April 2024

Abstract
This paper describes a methodology to identify bypassed oil in mature fields under a natural depletion drive mechanism, i.e., aquifer drive, using streamlines. For a reservoir system in a complex nonhomogeneous geological system, with multiple wells and many years of production history, the method leverages on well rate drainage pore volumes generated by a streamline numerical simulator. The methodology uses the concept of time-superposition by normalizing to rates the wells historical cumulative formation withdrawals to calculate and map historical drainage regions (HDR) on a well-by-well basis. Furthermore, it estimates the remaining, bypassed oil volumes in place from these drainage regions.
Characterization and Evaluation of Novel Zwitterionic Surfactants for Enhanced CO2 Foam for CO2 Sequestration in Saudi Arabian Reservoirs
Authors: Bashir Ahmed , Mahboob Ahmad , Hussain Syed M. Shakil , Patil Shirish , Kamal Muhammad Shahzad , Zhou Xianmin 
Published: April 2024

Abstract
This study aims to assess the foamability and foam stability of synthetic zwitterionic surfactants in a seawater environment, both in the absence and presence of oil. The primary objective is to determine their potential use in enhanced oil recovery (EOR) and CO2 sequestration within depleted oil reservoirs by determining the maximum foam stability. Moreover, the efficiency of surfactants is assessed by analyzing bubble sizes under different conditions. Finally, the effect of different concentrations of oil phases on foam stability under various conditions is studied. Two different zwitterionic surfactants (ZS1 and ZS2) were synthetically formulated and tested using ambient foam analyzers to evaluate their foamability and foam stability over time. Parameters such as foam height and foam decay were studied. A high-speed camera was employed to observe foam bubble sizes and coalescence. The performance of the surfactants is further evaluated under seawater and in the presence of different oil concentrations.
All examined zwitterionic surfactants displayed promising results concerning air and CO2 foamability and foam stability under different conditions. Foam generated through CO2 exhibits lower stability than foam created by air. Additionally, to understand the performance of the optimum foam composition in the presence of an oil phase at reservoir conditions, the foam was then brought into contact with different oil concentrations. The results show that foam stability decreased in the presence of different fractions of oil. However, the foam bubble size was not highly affected by the presence of oil. This observation is crucial as it indicates the potential longevity of foam stability in the presence of oil during both the EOR process and CO2 sequestration.
This research introduces an in-depth evaluation of in-house developed zwitterionic surfactants, highlighting their potential for EOR and CO2 sequestration in depleted oil reservoirs. The findings contribute a fresh perspective to the current literature, offering promising alternative synthetic surfactants suitable for different reservoir conditions in the petroleum industry.
Repurposing Idle Wells for Low-Temperature Geothermal Water
Authors: Qi Qianru , Tapsoba Mariam , Ershaghi Iraj 
Published: April 2024

Abstract
California has more than 40,000 idle oil and gas wells on record and similar data applies to the entire US. Some of these wells are located in areas with relatively high geothermal gradients. The temperature at the depths for many of these wells may be high enough that can provide opportunities for repurposing idle wells and accessing subsurface heat for low-temperature geothermal water before permanent plugging and abandonment of the well.
Based on an independent detailed heat map, we identified certain California oilfields that indicated high geothermal gradients. To verify, we also used the temperature data from well logs to establish the presence of high-temperature gradients. To access the heat, we considered the use of a closed-loop water circulation system for heat extraction from subsurface. We tested cases with bottom hole temperatures from 160 to 220 °F, geothermal gradient from 1.58 – 2.58 °F/100 ft, reservoir depths from five to twelve thousand feet, tubing with different insulation thicknesses, water circulation rate from 200 to 1,000 BPD, various temperatures of water sources, imperfect cementation, etc. Cases we considered included plugging the hydrocarbon-bearing formations and within the well circulation of low salinity water through annulus and insulated tubing.
In a case, a reservoir with the subsurface temperature of 190 °F maintains its temperature very well after 30 years after heating the circulated water at a rate of 800 BPD and deliver warm water of around 90 °F at the wellhead steadily. Results show it is the geothermal gradient, rather than depth or temperature at well bottomhole which determines heating power. Formation porosity and permeability do not affect the temperature of heated water in closed-loop system. A low circulation rate may increase the wellhead temperature with a condition of using high-grade insulation tubing. When temperature of source water is low, heating effect from wellbore is even more significant. Cement degradation does not hurt heating effect of wellbores that much, but such wells require careful mechanical examination before repurposing. Overall, we conclude that while some idle wells may not be used as conventional high-temperature geothermal wells, but some offer possibilities for space heating and agricultural greenhouse uses.
Some other states besides California are also experiencing increasing number of orphaned wells. This paper provides a technical basis for evaluating the feasibility of repurposing some of the idle wells for low-temperature geothermal energy extraction.
Integration of Geothermal Energy Recovery and Carbon Sequestration of an EGS by CO2-Water Mixtures
Authors: Xue Zhenqian , Ma Haoming , Chen Zhangxin 
Published: April 2024

Abstract
Enhanced geothermal system (EGS) has been acknowledged as a sustainable and low-carbon alternative for generating electricity. CO2 and water are two conventional heat transmission fluids in an EGS. However, the additional environmental benefits from storing CO2 in the reservoir cannot be achieved in a water-EGS, and an early thermal breakthrough or inadequate power production are the main obstacles in a CO2-EGS. This study introduces a co-injection of CO2 and water in an EGS development. Reservoir and economic models are constructed to compare the technical and economic performance of a water-EGS, a CO2-EGS and a CO2-water-EGS. The results indicate that the proposed CO2-water-EGS can produce more geothermal electric power than CO2-EGS and water-EGS, which can effectively solve the drawbacks of insufficient extraction rate in CO2-EGS, and meanwhile, improve the contribution in CO2 emissions compared to water-EGS. From the economic perspective, a higher Net Present value (NPV), an earlier payback period, a lower breakeven electricity market price, and a lower breakeven carbon credit rate are observed in CO2-water-EGS. Conversely, a not promising electricity generation and larger CO2 consumption make it hard to receive a higher NPV even though the highest carbon credit is earned. In addition, water-EGS performs a similar economic performance in contrast to CO2-EGS since it cannot obtain additional carbon credit although zero investment is required in purchasing expensive CO2. More importantly, CO2-water-EGS is the best option in changeable electricity market price, but CO2-EGS is better in profitability when the carbon credit rate exceeds $50/ton. With a comprehensive comparison of technical and economic feasibilities, this study provides the operators or stockholders with valuable insight into the operation strategy for EGS development.
Maximizing Hydrogen Yield: Pioneering Gas Injection for Enhanced Light Oil Reservoir Utilization
Authors: Okere Chinedu J. , Sheng James J. , Ikpeka Princewill M. 
Published: April 2024

Abstract
Sustainable hydrogen production is a key driver for accelerating global energy transition. This study evaluates the influence of injection gas composition on hydrogen yield during in-situ production of light oil reservoirs. In the study, three gas injection strategies: CH4+CO2, CO2+O2, and N2+O2 are investigated with the aid of dynamic reservoir simulation models and advanced reaction kinetics.
To conduct the investigation, a three-dimensional compositional reservoir model was built using CMG software and a fluid model consisting of ten light hydrocarbons and two non-hydrocarbon components was incorporated. Results from the analysis reveal that injection gas composed of CH4+CO2 yielded the most hydrogen consistently outperforms alternatives, not only in terms of cumulative hydrogen yield but also by contributing to carbon capture and utilization, aligning seamlessly with global sustainability objectives. This could be because the CH4+CO2 leverages on steam methane reforming and dry reforming of methane during in-situ combustion.
Comparing the performance of injection gas composed of CO2+O2 and N2+O2, the study underscores the limitations of combustion-dependent approaches and emphasizes the superior capabilities of reforming processes. CH4+CO2 is effective across a range of temperatures and mole fractions, making it the optimal choice for in-situ hydrogen generation within light oil reservoirs. The efficiency of CO2+O2 is contingent on oxygen availability, and N2+O2, while comparable, lacks the enhancement of methane in promoting hydrogen generation.
Ranking the performance of the three gas injection strategies investigated in this study, CH4+CO2 yielded the most cumulative hydrogen yield and hydrogen-to-syngas ratio, this was followed by N2+O2 and CO2+O2. These findings offer pivotal insights for refining operational parameters and advancing sustainable applications in enhanced hydrogen production within light oil reservoirs.
This research contributes not only to the ongoing discourse on sustainable energy solutions but also addresses efficiency goals and environmental concerns linked to greenhouse gas emissions. The practical implications extend to the energy industry, providing a pathway for sustainable hydrogen production within the intricate landscape of light oil reservoirs.
Patients´ experiences of an exercise intervention in primary care following robot-assisted radical cystectomy due to bladder cancer: A qualitative study
Authors: Karlsson Patrik , Nygren-Bonnier Malin , Torikka Simon , Porserud Andrea , Henningsohn Lars , Olsson Christina B , Rydwik Elisabeth , Hagströmer Maria 
Published: April 2024

Abstract

Background: Physical activity is thought to be a key component in reducing postoperative complications following major abdominal surgery. The available literature on exercise interventions following radical cystectomy in patients with bladder cancer is scarce but suggests that physical activity and exercise might improve physical function and health-related quality of life, thus calling for further investigation. The CanMoRe-trial is a single-blinded randomised controlled trial (Clinicals Trials NCT03998579 25/06/2019), aimed at evaluating the impact of an exercise intervention in primary care following robot-assisted radical cystectomy. This study seeks to explore patients' experiences of the exercise intervention in the CanMoRe-trial to gain a better understanding of facilitating aspects and potential barriers.
Methods: A qualitative study was conducted involving 20 patients from the intervention group of the CanMoRe-trial who were interviewed individually between October 2020 and March 2023 using a semi-structured interview guide. The interviews were recorded and transcribed verbatim and reflexive thematic analysis was used to analyse the data.
Results: Four main themes were identified: Having to adapt to new circumstances, describing the challenges regarding physical activity patients face after discharge. Optimising conditions for rehabilitation, describing how practical conditions affect patients’ ability to exercise. Motivated to get back to normal, describing patients´ desire to get back to normal life and factors influencing motivation. Importance of a supportive environment, describing the impact of social support, support from physiotherapists, and how the environment where exercise takes place impacts patients’ ability to exercise.
Conclusion: This study found that patients participating in the CanMoRe-trial are positive towards physical exercise in primary care following radical cystectomy. They are motivated to get back to normal life but face major challenges when arriving home following surgery, which affect their ability to perform physical activity and engage in exercise. Conditions need to be optimised to support patients’ ability to engage in exercise. A supportive environment is needed, including guidance from healthcare professionals enabling patients gradually to develop self-efficacy regarding exercise and focusing on goals related to patients’ normal lives before surgery.