bluuebunny/crossref_metadata_2025_split huggingface dataset:
Well Configuration and Placement Optimisation in Dual Media Systems Through Reservoir Modelling Approach
Authors: Al Mulhim Abdulrahim K. , Alnasser Mohammed H. , Alshubbar Ahmed K. , Hamam Hassan H. 
Published: October 2023

Abstract
During field development, evaluating and integrating various subsurface complexities and flow dynamics enable to generate optimum well placement blueprint. Hydrocarbon sweep efficiency can be enhanced through proper well configuration and layout. The well placement blueprint relies heavily on reservoir modeling to accurately determine well productivity and water encroachment by incorporating the reservoir's unique characteristics. This paper examines various well configurations and layouts that optimize hydrocarbon recovery while taking into consideration various degree of reservoir heterogeneities and uncertainties.
A synthetic dual porosity, dual permeability (DPDP) simulation model is utilized to analyze sweep and water encroachment. Multiple scenarios are developed by including various well configurations and layouts. Vertical, horizontal, and slanted wells are parametrized to evaluate the vertical and areal sweep efficiency. In addition to the well configuration, the role of wells’ spacing and orientation on sweep and well productivity is investigated. Various well landing zone and completion interval are incorporated in the analysis to capture the model's subsurface characteristics.
The DPDP simulation model provides insights on the possible well configurations and layouts to optimize sweep and enhance recovery. In-depth analysis for every scenario was performed to benchmark the impact of parametrizations on sweep efficiency, water breakthrough, and pressure propagation. The developed scenarios demonstrated the effects of well configuration on areal and vertical sweep efficiencies. For instance, slanted wells yield unique sweep signatures compared to vertical wells. Well landing zone and orientation played a major role on the overall recovery where vertical wells that were completed across the top zone can overcome horizontal wells completed in the bottom zone of the reservoir.
This paper reviews a systematic reservoir modeling workflow to optimize well configuration and layout by utilizing a DPDP synthetic model. The approach describes how to optimize hydrocarbon sweep and recovery by incorporating various degrees of subsurface complexities.
Automated Production Enhancement Candidates Screening Powered by Machine Learning Unlocks Untapped Potential in Matured Oil Fields – A Case Study
Authors: Mat Khair Nusheena , Zaizakrani M Farid , Zul Azhar Nur Afrina Inani , A Halim Fatin Liyana , Sidek Sulaiman , Nik Khansani Nik Zarina Suryana , Shafie Shar Kawi Hazim , Mokhlis Mohamad Mustaqim , Hazali Nurdini Alya , Saifuddin M Nabil 
Published: October 2023

Abstract
Field A, located offshore East Malaysia, has been a productive conventional oil field for more than three decades. Being a mature or brown oil field, it encounters several surface and subsurface including sand production, increasing water-cut and reservoir pressure depletion. Consequently, field production declines over the years. These issues have compelled the team to pursue for options to optimize the existing Field A's producing and idle wells in an effort to slow the production decline rates and keep up with field deliverability.
Failure to recognize and manage well behaviors may cause producers unable to meet production targets and experience other serious problems, such as well integrity. Hence, Production Enhancement Candidate Generation and Screening (PECGS), a Machine Learning (ML) tool, have been utilized in Field A to identify potential candidates for Production Enhancement (PE) from both active and inactive wells. The system has been able to establish a workflow that is capable of guiding and navigating the engineer through the process of identifying candidates for PE, such as zone changes (ZOC), Behind Casing Opportunities (BCO), add perforations and well stimulations that can be tracked all the way up to the execution stage.
This paper presents the processes of identifying production enhancement opportunities, as well as the methodology utilizes to identify underperforming candidates and analyze well integrity issues. It describes how data science and engineering analyses are integrated, and stresses how collective insights are gained from quantitative and qualitative outcomes, such as production increases, cost savings, operational efficiencies, and overall impact on field performance.
The implementation of well-engineered workflows has significantly aided and enabled users in identifying low-hanging fruit opportunities. This solution has created an efficient working environment, particularly for the team in Field A, empowering them to identify and capitalize on PE and Idle Well Reactivation (IWR) potential opportunities. By emphasizing the overall process flow from identification to results, this paper aims to provide a comprehensive understanding of the PE journey in Field A, showcasing the effectiveness of the approach and its contribution to the field's performance improvement.
Evolution of a Versatile HTHP Water-Based Drilling Fluid Improved Drilling Efficiency Offshore Vietnam
Authors: Moroni Luigi , Fatkullin Kamil , Tran Thanh Bao 
Published: October 2023

Abstract
The fast pace of exploration and production level increase over recent years has led operators to expand the horizon for exploration of hydrocarbons in more complex and exigent reservoirs which includes the high temperature and pressure (HTHP) reservoirs. Typically wells in the North of Vietnam have been drilled using a Non-Aqueous Drilling Fluid (NAF) for their lower and reservoir intervals. The challenges of multi-string design, potential of acid gas contamination, well bore stability, down hole losses and a high temperature environment require a well-engineered NAF to meet the overall well objectives.
Alternatively, Water-Based Fluid (WBM) has significant environmental benefits compared to NAF. This paper presents the technical development, evolution and lessons learned from using a high performance HTHP WBM over a series of extremely challenging HPHT exploration wells Offshore Vietnam, with temperatures expected to reach 170°C (338°F) and pressures over 12,000 psi. These conditions place severe limitations on the drilling fluid design and can often lead to failures in open-hole wireline logging operations, which is probably the most important objective in an exploration well.
To ensure the successful drilling, wireline logging and completion operations under the thermal conditions, the development of the HPHT WBM for these exploration wells needs to address the HTHP filtration control properties, filter cake quality, inhibition and the thermal stability of the drilling fluid. Extensive laboratory testing was performed to optimize the rheological properties for mud weights up to 18.7 ppg to ensure minimal sag tendency after static condition, while also providing excellent filter cake quality, system inhibition and hole condition to allow the well to be fully logged and evaluated.
The enhancements made in the HPHT WBM design led to an improved drilling performance in drilling these challenging exploration wells. Inhibition of the reactive formations was improved with each well drilled, as was the rate of penetration and wellbore stability. Extensive logging was performed with the wellbore remaining in excellent condition throughout the long open-hole time.
Water Injection Efficiency Improvement through UPD and RAM Analysis
Authors: Ali Zalina , Charil M Ayatollah , Mahmood Azizul , Daud Fairoz Irfan , Yusoff Noor Syaffynas , Sy Nadzir Sy Abu Bakar 
Published: October 2023

Abstract
Water Injection (WI) facilities design and operability of the system are crucial aspect in ensuring the treated water is meeting the specification and uptime required in compliance to the Reservoir Management Plan (RMP) target. Inefficient water injection facilities performance can result in lower equipment availability and reliability and pose a threat to injection uptime and impact the production gain. Sustaining injection to meet the target remain a challenge due to various facilities concerns including integrity and reliability resulting in equipment downtime, systemic issues, and operation surveillance and performance monitoring. Despite an integrated approach involving activity workflow and processes to ensure successful performance and operation are in place, less priority to WI facilities as compared to oil or gas production system resulting in lack of focus towards WI operation and maintenance response. This paper aims to demonstrate WI Facilities Performance Improvement via Unplanned Deferment (UPD) events deep dive analysis and Reliability, Availability and Maintainability (RAM) study. The UPD analysis focuses on identifying the UPD underlying root causes and threat for continuous facilities operation, subsequently crafted effective mitigation actions and solutions to overcome the issues. RAM studies were executed to assess the WI module capability in terms of the availability of the system and impact to the production. This is a holistic approach to assess existing WI equipment performance to sustain &gt; 95% uptime and meet the RMP target. Short- and long-term mitigation plans have been identified to elevate WI UPD focus within the organization including categorizing WI deferment category in the Production Deferment Management guideline and quantifying the impact of not injecting to the production gain to ensure WI UPD events can be tracked and high priority are focused on equipment maintenance response. The result from this specialized UPD and RAM study shows that opportunity improvement of 2%-15% based on the solutions in-place can further enhance WI system availability to achieve &gt; 95%.
Lesson Learned from the Hydraulic Fracturing of China's Shale Oil Field
Authors: Li Shuai , Cai Bo , Xin Jin , Yi Xinbin , Li Jianmin , Wang Mingxing , Li Jiacheng , He Chunming , Zhang Haoyu , Yan Xingming , Gao Yuebin 
Published: October 2023

Abstract
With the gradual deterioration of oil and gas resources quality, more companies are targeting the unconventional reservoirs. In China, unconventional reserves have accounted for more than 80% in total newly found proven reserves, taking tight oil for an example, China has tight oil geological resources of more than 12 billion tons.
In this paper, we firstly introduced the main geology and reservoir characteristics of the target block, the strong formation heterogeneity, low permeability, low abundance, etc. This kind of reservoir has no economical production without hydraulic fracturing, while the stimulation operation still faced with difficulties such as un-predicate fracture propagation, high cost and low efficiency.
Aiming to solve these difficulties, we summarized the status, experience and field application of the main hydraulic fracturing technologies in this area. (1) Horizontal well multi-stage fracturing (HWMF) technologies, featured with small well spacing, dense cutting, large fracture stages and small clusters, were widely used and applied as the main hydraulic fracturing method. (2) Widely used soluble sleeve bridge-plugs and soluble ball seats in the P’N’P completion wells, saving working time and reducing the construction cost. (3) Multi-functional fracturing fluids, featured with imbibition mechanism and increase oil recovery. (4) Replacement of ceramsite by low-cost quartz sand. (5) Factory-fracturing construction model, with maximum 12 well in one well platform.
The integrated technologies have been applied in more than 200 wells, the daily oil production per well has increased from 3-5t/day to 15-25t/day. Application of the integrated technologies and the experience can be references for the efficient development of similar tight oil reservoirs.
An Onshore to Offshore Conceptual Model to Characterise Structural Domain in West Timor Basin
Authors: Andaru Arkanu , Wiranatanagara Muhammad Budisatya , Madjid Muhammad Yusuf Abdul , Ardiansyah Nugraha , Kristian Jonathan 
Published: October 2023

Abstract
Despite its complex geological and structural conditions, West Timor holds great potential for petroleum exploration. However, a lack of data on the onshore area has made it challenging to fully understand the geological conditions that extend from offshore to onshore. This study aims to develop a geologic conceptual model that unravels the geological and structural complexity in West Timor by extending the geological understanding from onshore to offshore.
To achieve this goal, a play-based exploration methodology is employed, which includes geological field mapping and fluid sample analysis in the onshore area, and subsurface mapping using well and seismic data, 2-D palinspastic analysis, and basin modeling in the offshore area. A combination of land and satellite gravity data analysis is used to make basement depth estimations in both onshore and offshore areas, validated by well and seismic data. The geological analysis in the onshore area is then integrated with the analysis in the offshore area to obtain a complete geological understanding that extends from onshore to offshore and differentiates structural domains in the study area.
This study is able to construct a comprehensive geologic conceptual model and differentiate four structural domains (SD) in West Timor. These structural domains provide insight into the stratigraphical succession, basement depths, and other structural features that can help explain petroleum systems in the region. SD-1 is a normal horst-graben system, while SD-2 is thin-skinned deformation with a slightly deformed horst-graben system below imbricate thrust-fold system with a detachment surface penetrating Early Jurassic sediment (detachment surface in this domain is Aptian Early Cretaceous-shale of Darwin Fm.). SD-3 is similar to SD-2, but the detachment surface penetrates deeper into Triassic sediment (distal shale as part of prograding toe from Triassic sediment). Lastly, SD-4 is a highly deformed zone where the detachment surface penetrates the basement, resulting in a thick-skinned structure. The onshore area has the most deformed structure zones (SD-4 and SD-3) linked to fold-thrust belt geometry, making it more challenging for petroleum exploration. Meanwhile, the near-shore and offshore areas (SD-2 and SD-1) have less structural deformation. They are considered the most promising areas for hydrocarbon accumulation below imbricate thrust fold system (subthrust), as they still preserve the structural conditions and stratigraphic succession needed for accumulation.
The conceptual model constructed in this study offers a deeper understanding of the geologic and structural complexity in West Timor by integrating onshore and offshore data. By characterizing these structural domains, geoscientists can better identify areas with potential for petroleum accumulation and help synthesize a petroleum play concept in this area.
Assessment of CO2 Hydrate Generation During Sequestration in Depleted Hydrocarbon Reservoirs
Authors: Mousavi Mirkalaei Seyed Mousa , Rofieq Shodiq Khoirur , Bin Abdullah Ahmad Shahzwan , Khanifar Ahmad , Edmondson Mark Douglas 
Published: October 2023

Abstract
Carbon sequestration is the process of capturing and storing of atmospheric carbon dioxide (CO2) in the subsurface. The objective of any carbon sequestration project is to store CO2 safely for hundreds or thousands of years with a goal of reducing global climate change and net carbon emission. Based on preliminary studies depleted oil and gas reservoirs are considered good storage sites because they are well understood have already proven capacity to store hydrocarbons over millions of years.
Low abandonment pressure in these reservoirs provide an additional voidage-replacement potential for CO2 and allows for a low surface pump pressure during early period of injection. However, the injection process poses several challenges including the potential for hydrate formation.
This work aims to raise awareness of hydrate formation, which is a key operational challenge related to CO2 injection in depleted gas reservoirs. Hydrates, specifically CO2 hydrates, can significantly impact the efficiency and safety of CCS operations. This work provides a new approach to assess and anticipate the CO2 hydrate formation in the near wellbore region. A method for coupling a compositional dynamic simulator with flow assurance code using python is introduced to address the phase behavior of CO2 near wellbore under different operational conditions.
The proposed approach helps the reservoir engineer to anticipate hydrate formation in the early stage of project and plan to take necessary mitigation actions to avoid injectivity issue due to CO2 Hydrate formation. This work will also address the challenges associated with the numerical modeling of hydrate formation and dissociation, such as accurate thermodynamic modeling and phase equilibrium predictions.
The results from this work were identified several important parameters affecting hydrate formation during CO2 injection, namely injection temperature, reservoir pressure and thermal properties of the rock and fluid. It is important to pay attention to these key parameters to ensure accurate prediction of hydrate formation and dissociation phenomena. A sensitivity analysis was conducted to identify their effects on hydrate formation during the CO2 injection. The resulting tornado plot helped the study team to understand how quickly the hydrate can form after the start of injection. This helped the team to perform the necessary operational risk assessment.
Pre-Drill Geomechanical Modelling and Wellbore Stability Analysis for Successful Drilling in a Highly Overpressured Shale Zone and Potential Losses Carbonate Zone - A Case Study from West Tuban Block, East Java, Indonesia
Authors: Mikhael Chrislianto Reynaldi , Sagita Romi , Ghosh Amitava , Meidiya Putra Riko , Hisanah Nabilah 
Published: October 2023

Abstract
A high pressure well with a high risk of encountering a loss zone is a challenging drilling operation and requires a proper pre-drill study incorporating drilling practices, an understanding of the subsurface, and geomechanical modelling. This paper presents a case from the West Tuban Block. This block is within the East Java Basin, one of the prolific basins in Indonesia and a proven hydrocarbon reserve. The major challenge is drilling through the shale overpressure zone and the carbonate loss zone safely and successfully. This paper describes the building of a pre-drill geomechanical model, the subsequent wellbore stability analysis and how the results and recommendations were applied during drilling.
The geomechanical model was built using data from seven offset wells and also incorporated regional knowledge. The offset well review of the drilling experiences showed that the key challenges that will need attention are significant drilling problems such as pack-off and tight hole while POOH, RIH with casing and while wireline logging. Added to this are instances of losses and gains while drilling the carbonate reservoir section.
The geomechanical modelling process involves using petrophysical, geological, geophysical and drilling data to constrain the magnitudes of the overburden, pore pressure, rock mechanical properties and the two horizontal principal stresses. It is also important to constrain the azimuth of the maximum horizontal stress. The final model is verified using stress-related drilling problems and observations of wellbore failure in shale interpreted from caliper data.
The resultant geomechanical model suggests that the planned well is associated with a strike-slip stress regime. The magnitudes and azimuths of the stresses play an important role in successful drilling because the well is directional in the reservoir section with a maximum inclination ∼26°. The wellbore stability analysis was used to optimise mud weights for each hole section of the planned well. Recommendations were also made regarding additional data gathering (cores for conducting rock tests, extended leak-off tests, full suite of logs, etc.) to reduce uncertainty in the geomechanical model.
The mud weight and drilling practice recommendations, that were an outcome of the study, were followed meticulously by the drilling team so the well was able to safely overcome the overpressure zone and the loss zone. The effort contributed to the operator's success in the onshore development campaign with timely execution within budget and no reported HSE events.
Analysis of Accidents and Efficacy of Risk Management Practices of E&P Sector and Outlining More Pragmatic Approaches for the Management & Energy Regulators
Authors: Gaikwad Dheerendra Ajabrao 
Published: October 2023

Abstract
Accident patterns suggest, E&P sectors are struggling to professionally manage the EHS *(environment, health & safety related) hazard and associated risks emanating from their core businesses.
The author studied and analyzed the reported accidents from the last 8 years, along with their causes. It was observed that the root causes of accidents are very common, mere repetitions, and can be avoidable. This raises serious questions about the effectiveness of the existing EHS management practices/systems and also causes concern for management and other stakeholders. The author collected and relied on data from Tier-1* EHS (Environment, Health & Safety) accidents (1,808 incidents from the exploration and production sector worldwide) on a sample basis, which were reported and investigated.
The author analyzed the data and observed that the root causes of accidents are more associated with management and less with technical factors. Taking this into consideration, the author attempted to find a solution for the existing problems by utilizing appropriate management methodologies/approaches such as 6 sigma and Survivorship bias. Accidents occur due to coincidental failures of preventive/protective barriers at multiple levels, and the repeated patterns of these failures are a major concern for all stakeholders. By using strategic management tools/methodologies, the author ended up suggesting additional approaches/means to address the gaps in EHS management practices and achieve the desired EHS results.