bluuebunny/crossref_metadata_2025 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

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

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

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

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

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

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

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

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

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.
Advancing Decision Making In Field Operations And Maintenance: A Practical Risk Based Analysis Tool
Authors: Abdullah I. F. , Kusuma H. S. , Suryaputra C. H.
Published: October 2024

This tool is drawn from a variety of existing literature on decision analysis and risk management, adapting this concept to the practical challenges in the field. It's based on case studies from PT. Donggi Senoro LNG, where real-world scenarios are categorized and analyzed. This tool combines predictive analytics, which assesses spare part requirements using historical failure data, and multi-criteria decision analysis for choosing equipment overhaul providers and planning system upgrades. This approach standardizes inputs and assumptions in decision-making, enhancing the tool's applicability in diverse situations. It's a robust solution for efficient and effective risk management and decision support.

This tool is drawn from a variety of existing literature on decision analysis and risk management, adapting this concept to the practical challenges in the field. It's based on case studies from PT. Donggi Senoro LNG, where real-world scenarios are categorized and analyzed. This tool combines predictive analytics, which assesses spare part requirements using historical failure data, and multi-criteria decision analysis for choosing equipment overhaul providers and planning system upgrades. This approach standardizes inputs and assumptions in decision-making, enhancing the tool's applicability in diverse situations. It's a robust solution for efficient and effective risk management and decision support.

Application within PT. Donggi Senoro LNG has demonstrated the significant impact of this tool in optimizing decision-making processes. This tool has led to more transparent and informed decision-making processes. Decisions are now based on clearer criteria and better information, allowing stakeholders to understand and trust the process more. Its effectiveness is evident in more effective spare parts procurement, enabling the selection of optimal and economically viable maintenance service providers, and guiding appropriate system upgrades in a timely manner. These outcomes highlight the value of a balanced decision-making strategy, one that carefully considers both risk and economic aspects. This approach has not only streamlined operations at PT. Donggi Senoro LNG, but also presents potential benefits for the broader range of scenarios in the oil and gas industry, and potentially in other sectors of the energy industry.

This tool represents a new approach with represents a significant advancement in operational in decision-making within the energy sector. This tool brings a practical, easy-to-use solution to complex decision-making challenges, combining academic theories with real-world applications. The tool's development and application demonstrate a novel way of enhancing operational efficiency and strategic planning. Its adoption has the potential to set new benchmarks in operational decision-making, aligning with industry needs for efficiency.
Driving Operation Excellence: Shaping Operational Excellence through Competence Maintenance & Engineering Technical Executives for Superior Asset Integrity
Authors: Nordin Nadirah , Yusof Yushafidi , Syahriful Arie Pratiwi , Bawan M Zainuri
Published: October 2024

This manuscript explores the pivotal role of Maintenance & Engineering technical executives (M&E executives) in driving operational excellence and ensuring superior asset integrity within PETRONAS Upstream. It delves into the comprehensive competency requirements for these executives, emphasising the necessity of both technical skills and soft skills to lead teams effectively. In PETRONAS Upstream, M&E executives are crucial in orchestrating and executing strategies that enhance operations efficiency and improve asset performance in both oil and gas installation at onshore and offshore facilities. Recognised as Business-Critical positions, these executives are essential for the maintenance and efficient operation of equipment and machinery, particularly Safety Critical Elements (SCE), to minimise downtime and extend the lifespan of facilities.

To fulfill these critical roles, PETRONAS Upstream's M&E executives must excel not only in technical but also in leadership skills. Recognising this, PETRONAS Upstream Capability department has established a Maintenance & Engineering Structured Competency Development Programme (SCDP), a comprehensive career development structured guide. This SCDP focuses on equipping them with the necessary technical, functional, and leadership competencies, ensuring them to maintain high standards in Health, Safety and Environment (HSE) capabilities, possess commercial acumen, and uphold strong leadership values.

The manuscript also discusses the strategic use of data analytics to measure the success of SCDP. PETRONAS Upstream Capability department employs a data-driven approach to inform decisions, identify competency gaps, and ensure precise alignment of competencies with roles, thereby enhancing efficiency, productivity, and safety of the facilities. The M&E Analysis Dashboard, tailored to specific asset and function needs, exemplifies this commitment to continuous improvement. Additionally, this manuscript highlights the Assurance Programme, which ensures the consistent application and maintenance of these competencies to meet stringent safety and regulatory standards.

By examining these key elements, the manuscript underscores the importance of continuous capability development and its impact on operational performance. It presents a comprehensive approach in shaping operational excellence, demonstrating how a well-developed and competent workforce sets the fundamentals to achieve long-term success and sustainability in asset management.
Utilisation of CO2 to Carbon Nanotubes
Authors: Wattana P. A. , Thivasasith A. , Nunthakitgoson W. , Rodaum C. , Wattanakit C.
Published: October 2024

Capturing and converting CO2 into value-added chemicals and materials is of great interest for decarbonization. Among them, the CO2 conversion to advanced materials such as carbon nanotubes (CNTs) is a promising CO2 utilization. CNTs can be used in many applications, owing to its exceptional properties of high electrical conductivity, high thermal conductivity, high tensile strength, and high surface area. In this work, we have successfully developed catalysts and process to convert CO2 to CNTs. Active transition metal catalysts supported on zeolites were developed for the synthesis of CNTs using CO2 as raw material. The synthesis of CNTs from CO2 over the developed catalyst was carried out via a chemical vapor deposition (CVD) process. The quantity and quality of the carbon nanotubes synthesized from CO2 were determined using thermogravimetric analysis (TGA), scanning electron microscope (SEM), transmission electron microscopy (TEM), and Raman spectroscopy. A comparison between the current response of the synthesized CNTs and commercial CNTs were performed using cyclic voltammetry (V vs. Ag/AgCl) method. By optimizing metal type, metal loading, zeolite topologies and pore structures (hierarchically porous or conventionally microporous), the best CNTs were obtained over the 25wt%Fe on hierarchical FAU catalyst. The qualification and quantification of resulting CNTs were based on an average diameter size of 23.1 nm, a high yield of 15.4%, and ID/IG ratio (CNTs quality) of 0.56 as characterized by transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and Raman spectroscopy, respectively. The synthesized CNTs demonstrated improved performance in terms of current response compared to commercial CNTs when evaluated using cyclic voltammetry (V vs. Ag/AgCl) with a 0.5 M H2SO4 supporting electrolyte. This enhanced performance can be attributed to the small diameter and high quality of the synthesized CNTs. This work demonstrates the industrially relevant utilization of CO2 towards highly conductive CNTs-based materials, which have many potential applications including energy storages, sensors, electronic circuits, composite materials, etc. Transition metals like Fe and Ni play a crucial role as catalysts in the decomposition of CO2 during the CNTs synthesis. Well-dispersed distribution of metal nanoparticles on the hierarchical zeolite can enhance catalytic activity, consequently resulting in more favorable CNTs synthesis outcomes.
A New Semi-Iterative Well-Test Matching Method Based on Featured Points for Homogeneous Reservoir
Authors: Guo Xue , Chen Zhiming , Zhu Haifeng , Zhou Biao , Sepehrnoori Kamy
Published: October 2024

The accurate inversion of reservoir parameters is of paramount importance for the successful production of oil and gas. The well test is an important technique for achieving accurate reservoir parameter inversion. However, the challenge of balancing inversion accuracy and speed is present in existing well-test analysis. To tackle this challenge, two homogeneous well-test models with single and dual-porosity media are first presented for the study. Then, a new semi-iterative model (SIM) is used for well-test curve matching method based on featured points of these two well-test models. Furthermore, this study continues to compare the performance of the SIM, the formula-based analytical model (FAM), and the full-iterative model (FIM). It is found that the SIM can be more efficient and accurate to invert the parameters of homogeneous reservoir, because it can integrate the analytical and iterative inversion for each parameter. In addition, the analytical solution formulas for the storage capacity ratio and the interporosity flow coefficient in dual-porosity model are improved using the curvilinear method to achieve higher inversion accuracies. It is found that the median relative errors of parameter inversion for both single and dual-porosity media reservoirs are approximately 0.10% and 0.51%, respectively. The mean time for the SIM model to achieve both parameter inversion and matching of the well-test curves for the two aforementioned models is 2.36 seconds and 251.30 seconds, respectively. The time required for manual fitting methods that rely on human experience is reduced by approximately 90% or more. The results demonstrate that the SIM model proposed in this study is an accurate and efficient method for matching well-test curves of homogeneous reservoirs.
Design and Application of an Integrated Experimental Apparatus for Shale Scratch and Indentation Based on an In-Situ Environment
Authors: Liang Lihao , Meng Siwei , Tao Jiaping , Fu Hongtao , Lu Yunhui , Liu He
Published: October 2024

The proven reserves of shale oil are continuously increasing, with hydraulic fracturing being the key technology enabling its commercial exploitation. Compressive strength, fracture toughness, and hardness are important parameters reflecting the mechanical properties of shale. Research on these parameters can effectively guide fracturing operations and help identify optimal fracturing zones. Given this, it is of great significance to understand the mechanical properties of the entire shale formation.

This study designs an experimental apparatus for the integrated measurement of shale scratch and indentation based on an in-situ environment. The system combines the functions of shale scratch and indentation tests, allowing for scratch and indentation experiments by simply replacing the blade and adjusting program instructions. This novel scratch system enables continuous measurement of shale mechanical properties at an engineering scale. The designed temperature-pressure device replicates reservoir conditions. The device was used to evaluate the mechanical characteristics of various lithofacies in the shale basin.

Results are as follows. The device primarily consists of a scratch and indentation execution system, a data acquisition system, and a data processing system. The scratch and indentation execution system includes a horizontal movement subsystem, a vertical movement subsystem, and an execution blade, among others. These subsystems collaborate to conduct scratch and indentation experiments. The temperature-pressure device can simulate reservoir conditions for scratch and indentation experiments at temperatures ranging from room temperature to 150 ℃, and pressures ranging from 0.1 to 27 MPa. The device has been used to evaluate the mechanical characteristics and compressibility of four common shale lithofacies in the Songliao Basin. The study analyzed the evolution of shale mechanical properties under the influence of lamination, microfractures, and mineral composition. Different types of shale exhibit varying levels of fracturability, with siltstone shale demonstrating the highest fracturability, followed by laminated feisic shale, laminated diamictic shale, and finally, foliaceous shale.

Compared to conventional mechanical experiments and well logging results, the design of this experimental apparatus provides a convenient, economical, and precise method to study the mechanical properties of shale. The measurement results exhibit continuous variations and achieve millimeter-level accuracy, providing a robust theoretical foundation for hydraulic fracturing operations and identification of the optimal fracturing zones.
Successful Chemical Water Shut-Off Treatment in Heavy Oil Fields of India
Authors: Majumdar B. , Dayal H. S. , Kamble S. , Jayaraj M A , Kumar A. , Kumar A. , Mohanta P.
Published: October 2024

The instant paper relates to the successful water shut-off treatment in heavy-oil fields of India through squeezing polymer into the gravel pack completion well.

Santhal and Balol are heavy oil fields with viscosities ranging from 50 cp-1500 cp, API gravity 16-17°, permeability 3-5 darcy, and both fields are supported by active edge water aquifer support. Due to mobility contrast, viscous fingering is a prominent issue in the reservoir, further aided by high permeability, leading to the formation of high permeable streaks, resulting in a drastic increase in WC in wells.

To counter this problem, water shutoff jobs were carried out in the wells flowing with high water cut. Since the reservoir is highly unconsolidated and sand production is a challenge, all the wells are completed with Gravel pack. GP completion further complicates the water shutoff jobs in these wells as the standard practice requires GP retrieval and re-completion with GP, which is a costly affair and limits the number of jobs that can be taken up for WSO. To address this problem, bullhead WSO operations were carried out in Heavy oil fields, both with rig and rig-less methods. WSO in these fields has given very encouraging results with WC decreasing from ~95% to 70%. In some cases, no free water is observed after the job, indicating the sealing of permeable sand streaks which were contributing to the high water cut in these wells.

Rig-less WSO was carried out in 13 horizontal wells in these fields producing with more than 95% WC and reduction of WC observed in 10 wells with incremental oil gain of ~44 tpd. The average production time after the job was around 3 to 4 months before the wells again started producing liquid with high WC %.
Integrated Subsurface Evaluation of Telisa Sand in Lindai Field, Central Sumatra Basin: A Comprehensive Study on Geological, Petrophysical, and Reservoir Production Aspects
Authors: Thabrani Riksa , Dwiyono Imam Fajri , Soesilo Andy Try , Subhan Muhammad , Tobing James , Sipahutar Herbert , Hendrian Dicki
Published: October 2024

The Lindai Field is located in the operational area of the Siak Block, Kampar Regency, Riau Province, Indonesia (Fig. 1). The Siak Block oil field spans five regencies: Siak, Rokan Hulu, Rokan Hilir, Kampar, and Bengkalis. Exploitation of the Siak Block began by Chevron Pacific Indonesia in 1963. The Siak Production Sharing Contract (PSC) is divided into three blocks, with the Lindai Field located in Siak Area II (Fig.2), covering an area of 1600 km². Structurally, this field spans an area of 8.7 km². The Lindai Field in the Siak Block is situated in Riau Province, approximately 120 km from Pekanbaru. This is an old field that has been in production since 1974, consisting of five formations, including Telisa, Bekasap, and Bangko.

The Lindai Field is positioned to the west of the Petapahan Field in the Rokan Block. Based on the depth structure map of well SDA-032, it is located in the western flank area of the existing Lindai structure and is proposed as a well targeting the Telisa Sand as its primary objective. Telisa Sand is characterized by a high shale value and low permeability (tight sand), which has historically led to its perception as less productive and appealing. Therefore, it is necessary to integrate various evaluation methods to discover ways to optimize oil production in the Lindai structure, Siak Block. This endeavor aligns with the company's vision and mission to support the Indonesian government's target of increasing oil production to 1 million BOPD by the year 2030. This research delves into a detailed and comprehensive examination, integrating various scientific disciplines to evaluate the potential of tight sand in the Telisa Formation, encompassing geological, petrophysical, and reservoir production aspects. This comprehensive study will involve a detailed analysis of geological, petrophysical, and reservoir production data to evaluate the potential of the tight sands in the Telisa Formation. By integrating these scientific disciplines, the research aims to develop optimized strategies for oil production in the Lindai Field, ultimately contributing to the national goal of boosting oil output.
Automated Trend Identification and Alert System for Wells Monitoring in Mature Asset: Advantages and Challenges
Authors: Bahrim R. Z. Kamarul , Amir M. I. Mahamad , Wei T. Nian , Piah M. F. Mat , Manap A. A. Abdul
Published: October 2024

Manual monitoring procedures, while necessary, are sometimes inaccurate and inefficient. This study provides a proof of concept for an advanced automated trend identification and alert system intended to improve well monitoring in mature assets by detecting trends and anomalies in real-time and historical data such as production, injection, temperature, pressure, and gas-oil ratio (GOR). Meaningful insights were obtained through statistical analysis and used to inform the system's trend detection capabilities. The created system established its efficiency as an early warning mechanism for oil rim health by using unique data analytics to identify changes in water cut and correlate them with well flow line temperature. Despite issues with data quality and missing inputs, the system seamlessly integrates workflow, data management, analytics, and alarm creation, providing important qualitative insights into contact movement variances. This integration is especially important for enhancing reservoir management practices under constrained data settings, demonstrating the ability of innovative data processing approaches to overcome the limits of standard monitoring methods.
Feasibility Study of Conversion of Old Production Facility in Depleted Gas Field to CCS Facility Through International Joint Research with the Netherlands - Case Study
Authors: Cha Suho , Park Sunghyun , Kim Jonghwan , Park In Sun
Published: October 2024

The objective of this study is to ascertain the capital expenditure (CAPEX) and operating expenditure (OPEX) associated with the reuse of existing facilities. To this end, a joint research initiative has been launched with the Netherlands, which is engaged in a comparable Carbon Capture & Storage (CCS) project in the East Sea. The aim is to identify potential cost savings for the CCS project currently being prepared in South Korea. Among the numerous CCS projects currently underway globally, the Netherlands' CCS initiatives and the South Korean East Sea CCS project exhibit notable similarities. Both employ depleted gas fields submerged in the seabed as storage reservoirs and repurpose existing gas production facilities for CCS applications. The objective of this study was to evaluate the feasibility of a range of CCS project scenarios, including the potential for new installations, the reuse of existing gas production facilities, the suitability of different storage reservoirs (such as depleted gas fields or saline aquifers), the distance to injection wells, and the most appropriate transportation methods (such as pipelines or ships). In conclusion, it was demonstrated that the cost of recycling existing facilities could be reduced by more than 20% in comparison to the cost of new installations. Furthermore, it was established that pipeline transportation is more economically viable than shipping. Ultimately, a strategy for CCS projects utilizing depleted gas fields was developed through economic evaluation and comparative analysis. Given that all gas fields are ultimately depleted, this paper can provide variables, information, and cost-effective feasibility studies for engineers who intend to undertake follow-up projects involving the storage of carbon dioxide using old production facilities in depleted gas fields.
Operational Strategies and Cost Dynamics of Hydrogen Production: A Case Study in Malaysia
Authors: Shaffee Siti Nur Amira , Kassim Zamzila , Aminuddin Faris Akmal , Nozri M Aiman Irfan
Published: October 2024

In pursuit of achieving Net Zero Carbon Emissions (NZCE) by 2050, PETRONAS, Malaysia's leading energy company, has set ambitious decarbonization targets. Among the emerging pathways, hydrogen emerges as a promising alternative to traditional fossil fuels. This paper presents a comprehensive study focusing on the economic and environmental aspects of hydrogen production, specifically looking at Proton Exchange Membrane (PEM) electrolyzers for a refueling station in Malaysia.

Using advanced simulation tools like Symmetry iCON v2023.2, this study examines the operational parameters and performance characteristics of PEM electrolyzers. Through detailed analysis, factors affecting operational efficiency, such as cell voltage degradation, operational temperatures, operating pressure, and feed water flow rate, are explored. The findings highlight the importance of maintaining a minimum feed water volume flow rate to optimize operational temperature, while increasing operating pressure emerges as a feasible strategy to reduce both Capital Expenditure (CAPEX) and Operational Expenditure (OPEX). Furthermore, the study reveals the impact of operational strategies, such as isothermal operation, on Plant Power Consumption and module operating potential, revealing potential efficiency gains of up to 15%. Notably, the analysis also highlights the complex relationship between hydrogen and oxygen crossover within the electrolyzer, emphasizing the need for careful management to mitigate compressor power consumption.

From a cost perspective, the study shows that achieving a Levelized Cost of Hydrogen (LCOH) between $3-7/kg is possible, depending on operational improvements and local energy sources. However, to maximize the environmental advantages of hydrogen production, more work is needed to make sure the energy grid is cleaner compared to conventional steam methane reforming (SMR) processes.

This research provides valuable insights by presenting a method for simulating PEM electrolyzers on a process system level, giving a comprehensive understanding of the economic and technical aspects, as well as emissions implications. Additionally, by concentrating on hydrogen production in Malaysia, it advances our knowledge of hydrogen's potential in meeting affordability and sustainability objectives, in line with PETRONAS's NZCE 2050 target and wider energy transition goals.