bluuebunny/crossref_metadata_2025_split huggingface dataset:
Experimental Study on the Effect of Multiple CO2 Extractions on Wax Deposition in High-Wax Shale Oil and Prevention Recommendations
Authors: Liang Lihao , Meng Siwei , Tao Jiaping , Lu Yunhui , Liu He , Fu Hongtao 
Published: October 2024

Abstract
CO2 fracturing and flooding have become key technologies for increasing shale oil recovery. However, for shale reservoirs with high wax content, the production data from Daqing oilfield indicate lower later-stage recovery rates and a significant occurrence of wax deposition during production employing CO2 injection. Therefore, it is crucial to clarify the applicability of CO2 in high-wax shale reservoirs.
This study focuses on high-wax shale oil from the Qingshankou Formation in the Songliao Basin, China to explore the wax precipitation temperature and composition changes before and after CO2 extraction. Initially, the shale oil underwent repeated CO2 extractions and the variations in wax precipitation temperature and crystallization characteristics were analyzed. Subsequently, chromatographic column analysis was employed to examine the crude oil compound composition before and after CO2 extraction. Finally, the wax precipitation mechanism was explored, and corresponding suggestions were provided.
Research suggests that after multiple CO2 extractions in the high-wax shale oil, light hydrocarbons decreased, the wax precipitation temperature and wax yield increased, and the wax crystal morphology became denser. After three cycles of CO2 extraction, the saturated hydrocarbon content in shale oil decreased by 21%. This may be attributed to the reduced solubility of crude oil in wax crystals due to CO2 extraction of light hydrocarbons. As a result, the content of heavy hydrocarbons such as asphaltene increased, providing more nucleation sites and accelerating wax precipitation. The deposition of organic solids such as paraffin causes damage to the micro-nano flow channels in the reservoir, increasing the flow resistance of the crude oil. Therefore, the development of high-wax shale oil reservoirs can be addressed by employing chemical inhibitors, optimizing CO2 flooding technology, and changing extraction methods. The comprehensive application of various technological approaches and effective reservoir management can mitigate the adverse effects of wax precipitation on the reservoir.
This study investigates the applicability of CO2 to high-wax shale oil reservoirs, and challenges traditional perceptions of CO2 fracturing and flooding techniques benefiting all shale oil reservoirs. The corresponding recommendations provided in this paper serve as technical insights for the development of such reservoirs.
Engineering Sustainable Careers: Exploring Parenthood Timing Factors among Engineers in Australia
Authors: Triharta M. , Monzon V. S. , Male S. , Wong E. 
Published: October 2024

Abstract
The sustainability of qualified female engineers’ careers in Australia is challenged at the critical childbearing age, with evidence pointing towards masculine professional cultures and a specter of reproductive choices as potential risk factors for low fertility among female engineers in the profession. In this paper, factors influencing decisions on the timing of parenthood for both female and male engineers in Australia are explored across different personal life stages within their professional careers.
This study employed a qualitative method of semi-structured interviews with a total of twenty female and male engineers in Australia. The interviews harnessed an interactive component where participants were asked to graphically time-map their engineering career while retrospectively reflecting on their parental aspirations and the factors that influenced them at different periods of their journey. Factors that accelerate or delay reproductive timing were identified with respect to the time period when the factors were most salient.
The study identified a multilayer of factors, namely: (a) individual; (b) inner circle, such as spouse and family; (c) organizational; and (d) profession/industry — that critically influence decisions on the timing of parenthood. Most participants identified age and individual or their spouse's economic and career securities as crucial factors. At the organizational and industrial level, hypercompetitive organizational culture, i.e., the shared drive for results rather than development; the business nature of the organization, i.e., project-centric versus continuous operation work structure, and its geographical presence affected both male and female engineers’ decisions and may delay their reproductive timing.
The study identified several delaying factors that were prominent among female engineers and absent in their male counterparts. These included: professional identity, hostile work environments towards women, especially when experienced at an early stage of their career, absence of role-models, and the fast-moving skills and knowledges in the engineering profession and/or industry attached to a fear of skill obsolescence.
This study's significance lies in exploring the uncharted topic of differences in reproductive choices and the institutional environment where they take place. The study theorizes these differences as a developmental process tailoring comprehensive organizational strategies for people at various life stages, thereby enhancing their career sustainability in the profession.
Technoeconomic Evaluation of Ammonia Cracking for Hydrogen Production: A Question of Colors and Scale
Authors: Shaffee Siti Nur Amira , Aminuddin Faris Akmal , Nozri M Aiman Irfan , Kassim Zamzila , Panuganti Sai Ravindra 
Published: October 2024

Abstract
The hydrogen economy has experienced rapid interest in recent years, emerging as a promising pathway to decarbonization. Despite its potential, hydrogen affordability is still a massive challenge particularly due to its requirement for renewable energy. For long distance hydrogen transport, ammonia is explored as a viable medium due to its matured and scaled existing infrastructure. This study delves into the role of ammonia as the hydrogen carrier, with a focus on evaluating the techno-economic viability and emission of ammonia cracking process.
A comprehensive techno-economic analysis was conducted across two distinct ammonia cracking scales, between 4,000 tons/year and 400,000 tons/year of ammonia. The ammonia cracking process simulation model was built using the Symmetry-iCON software and includes main process units such as ammonia dehydrogenation, flue gas production and hydrogen purification. Assumptions were made on the efficiency of 99% of hydrogen production. We further employed a factorial method to estimate the capital expenditure (CAPEX) of the plant, a critical component in our analysis. Operation expenditure (OPEX) estimation was included by considering factors such as cost of raw material, electricity and manpower.
The techno-economic analysis shows significant differences between two scales of operation. At the smaller scale of 4,000 tons/year, the minimum hydrogen selling price to achieve 20% IRR is 14.3 USD/kg H2, while at the larger scale of 400,000 tons/year, the price reduces to 3.7 USD/kg H2. Additionally, the analysis reveals OPEX, especially the cost of ammonia (grey, blue and green) is the primary cost driver in ammonia cracking process. A sensitivity study on ammonia costs reveals that fluctuations in OPEX have the most significant impact on hydrogen costs, compared to variability in CAPEX. Other operational costs considered within this work include installation of equipment, transportation and maintenance of the equipment. The fuel type and mix were studied to understand their impact on the overall system emission. The cases considered include the use of methane, a mix of methane and hydrogen and direct use of ammonia as fuel for the cracking system.
This study provides valuable insights into the techno-economic aspects of using ammonia for hydrogen storage and transportation. While ammonia cracking is technically viable for hydrogen production, its economic feasibility depends significantly on the scale of operation and ammonia cost. From a technological perspective, alternative pathways that could lead to lower energy consumption could further lower the cost of ammonia cracking.
Integrated Casing Wear Management in Well Design and Drilling Operations with a Field Case Analysis
Authors: Liu Yongjun , French Pete , Skinner Graham , Gleizes Louise , Bisset Peter , Gajare Sagar , Kelleher Denis , Razzetto Marco 
Published: October 2024

Abstract
Casing wear is an ongoing concern for well integrity especially in deep wells. Severe casing wear especially on the production casing, which normally serve as secondary barrier of a well, can result in downgrading the pressure capability, significant remedy costs, or even the loss of a well. The casing wear shall be managed from both design and operational phases to ensure well integrity not affected by casing wear.
Casing wear is the mechanical work of friction between the contacting areas of drill string and inner wall of casing. There are different casing wear mechanism and wear patterns because of the movement of drill string. An industry standard casing wear model was used to compute crescent-shaped casing wear. The three major inputs for the model are: side force at drill string and casing contacting aera, wear factor and total string rotating revs. Compound casing wear also discussed for the mechanism and contributing factors.
Practices both in well design phase and drilling phase are summarized in paper. Side force shall be checked in well design phase with planned dog-leg severity, expected hook load and wear factor. Excessive side force should be avoided from well design phase to reduce the risk of severe casing wear. In drilling phase, the actual wellbore tortuosity and max dog-leg severity need to be monitored and managed to below threshold defined in well plan. Operationally, the ditch magnet metal weight shall be recorded on daily basis with monitoring against krevs, time and distance drilled, and the drill string tool joint hard-banding worn status also shall be recorded for the depth and worn severity. Those data points will be analyzed to build relations with daily string revs and footage drilled.
A representative field case is used to verify the casing wear modeling validity and effectiveness of casing wear management practices. The casing wear modelling outcome identically matches the peak sections from the ultrasonic (USIT) casing wear logging results. The high side force interval depths recorded high casing wear. The drill pipe tool joint hard-banding wear section also matches the high side force intervals in top hole.
This paper should provide help on casing wear prediction and mitigation. The paper verified the casing wear model and provided wear factor reference for a certain drill string, mud property and casing grade. Some recommendations are proposed for casing wear mitigation.
An Analysis of Secondary Component Placement Using Shaped Polycrystalline Diamond Compact Cutters in Conjunction with a Fixed-Cutter Drill Bit Design
Authors: Sutan M. A. , Aribowo T. H. , Thomas A. X. , Bailey M. J. , Hawa T. , Wibbelmann N. , Fawcett A. 
Published: October 2024

Abstract
This paper examines the impact of using shaped polycrystalline diamond compact (PDC) cutters on the secondary element that tracks behind them on the same blade in a fixed-cutter (FC) drill bit. By conducting meticulous analysis and employing sophisticated modeling techniques, it is possible to strategically position the component to guarantee performance with minimal adverse effects on performance and stability.
The analyses were undertaken using geometrical modeling of FC drill bits with a designated cutter configuration and secondary element positioned behind them. A representative field data analysis was conducted to ascertain an appropriate target depth-of-cut (DOC) value for the bottom-hole pattern simulation. The geometric model calculates the engagement area of the secondary elements and the impact of the shaped cutter configuration. This is combined with a drilling mechanic simulation to observe the effect on the behavior of the cutting structure. The simulation result was then compared to the field for correlation, and the analysis result was used as an input to optimize the secondary element placement for further validation in field trials.
Shaped PDC cutter configurations are often used to replace legacy round cutters on an existing drill bit cutting structure to optimize the drilling performance of the bit. This alteration is frequently implemented without careful consideration of the existing secondary elements, which may prevent the realization of the full benefits of the shaped cutters. Interactions between primary and secondary cutting structures influence the secondary element engagement setup, resulting in varying drill bit performance behaviors.
The modeling results indicate that PDC-shaped cutters expose the secondary element more at the same DOC than round PDC cutters. Additional comparative simulation agrees that secondary element engagement occurs earlier, which may adversely influence the performance of the drill bit. The research findings demonstrate that the precise placement of secondary elements is critical when configuring fixed-cutter drill bits with PDC-shaped cutters. Optimizing the secondary placement on a drill bit with PDC-shaped cutters enhanced the performance of the bit by achieving the desired engagement area at the target DOC for the intended application.
Successful deployment of shaped PDC cutting structures nowadays requires understanding and optimizing the secondary elements placed behind them. This paper investigates one approach to evaluating and proposing optimal placement to enhance the cutting structure efficiency. This drill bit design optimization has the potential to enhance drilling efficiency and reduce drilling cost per foot, as well as reduce overall downhole vibrations, which can lead to reliability issues within the drill bit and bottomhole assembly.
Integrated Subsurface Study to Enhance Karst Reservoir Characterization: A Proactive to Maximize Recovery of a Large Gas Field in Malaysia
Authors: Sagar S. F. S. Wan , Trianto A. , Hendraningrat L. , Sedaralit M. F. 
Published: October 2024

Abstract
One of the challenges in conducting integrated subsurface study in this project was to construct the Karst model with enhanced seismic data. The previous model did not include Karst which should be very important for well placement purposes. Hence, the study objective is to develop 3D Karst map to feed seamlessly into static model for better reservoir characterization and maximize gas recovery through better development plan, including well placement.
The critical part of the karst building workflow was to screen extracted Karst as a geobody using many volume attributes, as it requires good understanding of how geology works on that particular area. A very comprehensive geophysical workflow has been developed accordingly. Some inhouse technology were developed to enhance seismic data interpretation and consequently to have better understanding in reservoir characterization and performances by introducing karst feature and multiple probabilistic production forecasting for risks quantification. Geomechanics and uncertainty analysis on subsurface uncertain parameters were conducted following to probabilistic dynamic modeling workflow (PDMW) guideline.
The 3D Karst mapping to feed seamlessly into static model was very challenging whether or not to maintain a lateral karts networks considering that the global sea level changes in this area while the seismic internal zones identified are 7 reflectors but only 2 are calibrated with GR log. In the generated static model, it was identified that the Karst body contributes additional 1.3 TSCF of GIIP compared to the previous static model without Karst. Forecasted recoverable reserves from probabilistic modeling approach were simulated using P90, P50, and P10 static model realizations which represent P90, P50, and P10 distributions of gas initially in-place. Vertical permeability was quantified as the most uncertain parameter which could either increase or decrease the forecasted recoverable reserves further. A 4D Geomechanical model incorporating karst feature for the entire field life has been developed and can be used for both present day and future field planning.
The outcome from this study is to propose subsurface development plan with optimum number of gas producer wells. In addition, gas recoverable reserves were further optimized by lowering down tubing head pressure constraint without impacting topside facilities and export duty. The gas recovery can be maximized up to 80%.
Using Molecular Dynamics Simulation to Estimate Storage Capacity in Depleted Gas Reservoirs for Underground Hydrogen Storage
Authors: Doan Quoc Truc , Keshavarz Alireza , Behrenbruch Peter , Iglauer Stefan 
Published: October 2024

Abstract
The Underground Hydrogen Storage (UHS) project, a significant potential solution, not only offers clean fuel but also holds the promise of replacing traditional fossil fuels, thereby significantly reducing CO2 emissions. Subsurface geologic formations, particularly depleted gas reservoirs, have been identified as crucial geological targets for injecting and storing H2 into underground formations for CCS and UHS projects. Accurate storage capacity assessment requires estimating the amount of H2 that can be safely stored in underground formations is essential. Because H2 injection in depleted gas reservoirs can escape through caprock as the breakthrough pressure of injected gas is above the capillary entry pressure, which is described as a function of contact angles (θ) and interfacial tensions (γ) and effectively capillary (or pore) radius. While experimental measurement of γ and θ can be challenging and inaccurate under reservoir conditions, especially in high pressure, high temperature or the presence of toxic gas (H2S) or flammable gas (CH4 or H2), Molecular dynamics (MD) simulations have been conducted to accurately determine the γ and θ under extreme conditions without safety concerns. This study presents an approach of Molecular Dynamics (MD) simulations to predict interfacial tension and contact angle and investigate the effects of an H2-CH4 mixture to assess gas column height. The study indicates that the difference between MD and experimental outcomes is less than 5%. Furthermore, in the case of shale as caprock, the gas column height in depleted reservoirs reduces with increasing H2 concentration in an H2-CH4 mixture. It offers a solution to quickly evaluate the impacts of risk and uncertainty of key parameters (such as interfacial tension, contact angle or density difference) in assessing H2 column heights in depleted gas reservoirs. The advancements made in this study significantly contribute to the de-risking and safety of large-scale UHS projects, thereby instilling confidence in the successful decarbonization of the energy supply.
Why One Size doesn't Fit All: A Tailored Approach Toward Diversion Design Generates Incredible Results through Improved Zonal Coverage
Authors: Hamid Saad , Hoong Marcus Chan Choon , Almulhim Abdulrahman A. , Al-Aqeel Abdulaziz O. 
Published: October 2024

Abstract
The objective of this publication is to showcase the effectiveness of well stimulation using an innovative acid fracturing technique in water injectors, which offers long intervals and low temperatures in target zones. The scope includes the concept adopted for the acid fracturing design and, subsequently, the evaluation performed taking into consideration the effectiveness of various diversion techniques in comparison with the synergies explored in this particular approach.
A tailored high-rate acid fracturing treatment system was devised with the use of hydrochloric acid, a viscous fluid, and a diverter. The system was then tested in alternating steps to ensure deep etched fracture length and diversion across the long interval may be achieved. Two different diverting techniques using coarse size granular salt and fiber laden self-diverting acid, were evaluated. Post-stimulation evaluation was carefully formulated and deployed using injectivity spinner to evaluate the effectiveness of each diverter. The results obtained from this evaluation were examined and recommendations were generated for subsequent treatments in similar conditions.
A wide variation in diversion behavior was observed with both diversion systems, with one showing a lower pressure increment than other. The spinner survey was also aligned with the pressure trend. After the spinner survey evaluation, diversion design was further tuned, which enabled even more effective diversion in subsequent operations. The effectiveness of design modification also translated into greater gains in overall post-stimulation injection performance.
Utilizing Machine Learning to Unlock Subsurface Production Potential
Authors: Zaizakrani M. Farid , Sidek Sulaiman , Surin Nicholas Aloysius , Ching Yap Bee , Muniandy Satyaraj , Hazali Nurdini Alya , Mokhlis Mohamad Mustaqim , Saifuddin M Nabil 
Published: October 2024

Abstract
One of the ways to unlock subsurface production potential in a brown field is via Behind Casing Opportunities (BCO). The conventional method of assessing remaining hydrocarbon potential by deploying logging tools downhole may be challenging in some fields, especially those with highly deviated or horizontal wells. A novel BCO identification process discussed in this paper leverages Machine Learning (ML) model within an Artificial Intelligence (AI) framework that integrates petrophysical data, dynamic production attributes, and production potential using automated calibrated models to identify unperforated zones in existing wells and spot those with significant production potential. The methodology involves defining target variables, selecting input features, choosing a modeling approach, and characterizing uncertainties. The datasets encompass well construction details, reservoir petrophysics properties, dynamic production attributes, and the production history of neighboring wells. Employing sophisticated algorithms like Artificial Neural Networks (ANNs) and random forests, the model undergoes dynamic training to refine its accuracy and reliability. These optimal settings are then preserved for final deployment, with a detailed analysis of uncertainties to support informed decision-making.
This paper introduces a novel application of an Artificial Intelligence and Machine Learning (AI-ML) framework for BCO identification, providing unparalleled insight for the O&G industry. It features an in-depth validation process, the step-by-step deployment of innovative methodology, and revolutionary strategies to enhance production in challenging wellbore conditions and complex reservoir environments.