bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanism and Oil-Water Pressure Drop of Unique Autonomous Inflow Control Device Under Different Water Cut: Water Control Performance of AICD in Large Bottom Water Reservoir in South Sudan
Authors: Khan Javed Akbar , Chen Yanhong 
Published: February 2025

Abstract
Water control for a longer time is a challenge. This paper present the effectiveness of water control performance of existing devices and valves including Inflow Control Devices (ICD), Autonomous Inflow Control Devices (AICD), and Autonomous Inflow Control Valves (AICV) in various wells. Any device is usually considered based on working principles and performance at the start of production. However, consideration of the structural integrity of a device is important for its longer effectiveness in controlling water until the end. Also, the ICV, ICD/AICD/AICV, DHPG, and PPL selection depend on reservoir condition. The presented comparison can be part of the selection procedure of these options. It shows realistically smart option in the scale/corrosive/hydrate environments to control water for a longer time. This paper shows advanced intelligent water control technology that can control water influx, enhance oil recovery, and manage pressure in multi-layer reservoirs. The innovative design of the inflow channel structure restricts water based on viscosity and density differences of fluids. It can automatically adjust pressure drop, has no moving parts, has an integrated design, and can function throughout the entire life cycle of the oil well. The mechanism of advanced Flowise® AICD is illustrated which shows significant pressure drops for water, and its effectiveness under different water cuts. Finally, performances of AICD completion in a field operated by PETRONAS in South Sudan is presented. Apart from AICD completion, perforation in selected layers were performed for production enhancement solution. The following are the key results that show a significant reduction in water and high oil production after the work over; Before Flowise®: Water Cut = 92.9%; After Flowise®: Water Cut = 24.9%. Before Flowise®: Qo = 139bbl/d, Qw= 1819bbl/d; After Flowise®: Qo = 942bbl/d, Qw = 313bbl/d. This paper also discusses the optimal operating conditions for AICDs/AICVs, which rely on viscosity and density differences, in Oil/Water and Oil/Gas systems. It emphasizes the importance of selecting devices based on fluid characteristics for long-term performance. Moreover, the selection based on the structural stability and reliability of any device/valve is important for extended service life, highlighting the need for maintenance-free tools that align with a well's lifespan and effectively choke water at later stages.
Enhanced Reservoir Characterization of Thin Coal Seams: Application of 2D CNN-Based Seismic Impedance Inversion in Deep CBM Exploration
Authors: Li J. , Sun J. , Zhang H. , Sun X. 
Published: February 2025

Abstract
Deep coalbed methane (CBM) exploration presents unique challenges in reservoir characterization, particularly when dealing with thin coal seams. This study introduces a novel application of two-dimensional Convolutional Neural Network (2D CNN) based seismic impedance inversion for characterizing the No. 8 coal seam in China's Ordos Basin. By integrating post-stack 3D seismic data with limited well log information, we achieve high-resolution impedance inversion across an 80 km² deep CBM block in the Daji area. The results demonstrate superior accuracy in delineating thin coal seams compared to conventional inversion methods, validated through blind well tests. The resulting high-resolution impedance model enables well data-driven reservoir characterization, including porosity, ash content, and gas content estimation, providing crucial insights for well placement optimization and horizontal well trajectory design.
Unlocking Production Potential: First Successful Deployment of Multilateral Completion Feed-Through Selective Lateral Access Window with Intelligent Completion
Authors: AlRaml Haidar , Jacob Suresh , Widjaja Danang , Almasri Abdulrakeeb 
Published: February 2025

Abstract
The continuous advancement of multilateral completion technology has significantly transformed the oil and gas sector by enabling access to the reservoir. This has resulted in a substantial influence on production capacity. This abstract analyzes the latest progress in multilateral completion technology, specifically highlighting the incorporation of intelligent completion systems and lateral access throughout the lifespan of the well. The monitoring system has effectively utilized the acquired data, resulting in an improved accuracy and efficiency.
The efficacy of the Multilateral selective lateral access window has been demonstrated over the last few decades. It has successfully identified reservoir problems and implementing necessary measures based on obtained data. A substantial advancement in this field has been made by the creation of an advanced completion lateral access window. This window enables the placement of the PDHG and flow control devices below, and in close proximity to the reservoir. Consequently, there has been an improvement in the monitoring and control of the main bore. This innovation led to a substantial revolution in the implementation of drilling and completion deployment.
Practical knowledge has demonstrated that the integration of intelligent completion technology into gas and oil wells enables precise evaluation and strategic planning through the utilization of predictive analytics. By utilizing these analytics, one can gain a more profound comprehension of the reservoir's behavior. This allows for predicting its future performance and devise a proactive strategy for decision-making that will maximize the effectiveness of the well and the entire field. This ultimately leads to enhanced economic recovery and advantageous outcomes. The well has been granted favorable conditions because of the most recent development of a multilateral lateral access window, which enables access for any essential operation in order to maximize its capabilities. Preventing the necessity for well completion removal while enabling well access is a critical element in extending the well's operational lifespan. The progress made in multilateral technology has significantly expanded the practicality and relevance of the information, consequently improving the implementation of intelligent completion.
Significant advancements in this field are made possible by the Feed-Through selective lateral access window, which grants access for any required intervention for the duration of the well's existence.
This paper will focus on the recent development in multilateral completion technology, with a special emphasis on the capability to access both laterals in wells completed with intelligent completion.
Innovative Spacer and Slurry Design to Cure Severe Losses in Depleted Formations: A Case History from Southern Oman
Authors: Turner Jamie , Aly Ahmed 
Published: February 2025

Lost circulation while drilling is a common problem and a significant challenge in global drilling operations, particularly in weak, unconsolidated, or fractured formations. This phenomenon contributes to nonproductive time and imposes a substantial financial burden on well-construction economics, with estimated global costs reaching USD 2 billion annually (Alkinani et al. 2021). Despite numerous attempts to strengthen the wellbore through experimental processes and studies using modeling and simulation (Feng et al. 2024), these challenges persist, negatively impacting operations. The need to lift heavier and more viscous fluid through a narrow annulus increases equivalent circulating densities (ECDs), often exceeding the fracture limits of the target zone. This can lead to a lower-than-required cement top, potentially affecting overall well integrity and the final zonal isolation objective.
The traditional technique of curing losses using drilling fluid lost-circulation materials (LCMs) often serves as the final plan of attack. In parallel, recent advancements in bottom-hole assembly (BHA) technology have grown to meet the challenge of successfully drilling more sophisticated wellbore geometries under harsh conditions. One such advancement is the inclusion of a mechanically activated side port above the critical BHA components. This port, when activated, diverts the flow of cement fluid away from the BHA, reducing the potential risk of pumping cement fluid through the BHA. However, this solution does not address the added risks of a stuck BHA (Lavrov 2016) due to the inherent nature of the reactive cement systems and formation challenges. It is important to note that bypassing the fragile components of the BHA is not the only mitigation; an optimized job procedure should be assessed to minimize any potential error in reactive treatments. Traditionally, the safest procedure involves pulling the drill string and BHA to the surface, then using a single-purpose, sacrificial work string to place reactive fluids and thixotropic cement to seal and strengthen the problematic section. However, this approach incurs additional flat time due to the often high number of hours needed to trip and run the work string for treatment application. Meanwhile, losses continue to occur under static conditions, adding to the challenge. Finally, the inefficiencies of this approach are compounded if the problem of loss circulation while drilling requires multiple attempts for success.
Managed Pressure Cementing Allowed Flexibility of Adjusting 3-Variables to Minimize the Losses Rate Instantly During Cementing Hence Assuring Well Integrity, A Case Study
Authors: Uddin Muhammad Jamal , Iturrios Carlos , Irawan Fikri , Alzahrani Abdullah 
Published: February 2025

Abstract
Both cement quality and quantity play a major role in well integrity. The quality of bonding between casing and cement can be maintained if no downhole fluid losses occur during the cementing operation. For quantity aspect, relying only on the total cement volume pumped will not guarantee that the planned cement height in annulus is achieved. During job execution an induced fracture might cause considerable cement column to be lost into the opened fracture-zone.
The reason for this higher bottomhole pressure are primarily due to the high rheology of the cement slurry and spacers and also the annular space between the casing assembly and bore hole is lesser as compared to the drilling assembly during drilling phase which generates higher annular friction pressure losses aiding to the high bottomhole pressure. In addition the density of the slurry and spacer is usually higher than the drilling fluid which also further increases the bottomhole pressure. All these three factors make the likelihood of lost circulation more than during the preceding drilling phase.
The case study highlights how these challenges were addressed during cementing. Initially by designing a lighter mud density used in combination of surface back pressure, SBP improving the density hierarchy of the cement to reduce the chances of contamination. Additionally utilizing the early kick/loss detection system to instantly detect and minimize the losses during the job execution.
After Managed Pressure Cementing simulations a lighter MPC mud, 123pcf was proposed which in combination with the SBP and pump-rates will provide flexible EMW adjustments if required. It was planned to adjust the cementing pump-rates to minimize the high bottomhole frictions during the operations as dictated by the loss rates. The cement hardening time was pre-adjusted accordingly by adding the necessary retardants.
Throughout the cementing operation, the well was monitored closely using the early kick/loss detection system and suggested to reduce the ECD first by reducing the SBP and then by reducing the pump-rates. Enabled flexible EMW adjustment by fine tuning either SBP or pump-rates real-time as dictated by the losses. The ECD was managed real-time and almost instantly. Total 15-18bbls only was lost during entire cementing ensuring proper well integrity.
Minimizing losses during cementing operations is imperative for achieving adequate zonal isolation. The most common well integrity issues involve fluid migration through leakage pathways. Also, the dynamic pressure and temperature conditions during drilling and production exert a cyclic load on cured cement, and sometimes initiates cracks in the cement. These cracks then have the potential to act as pathways for fluid migration. Therefore avoiding troubles during primary cementing is essential for assuring well integrity.
Optimising Well Placement in an Unconsolidated Reservoir Using High-Definition Reservoir Mapping and Rotary Steerable System: a Case Study in South China Sea
Authors: Gao Yongming , He Lipeng , Jiang Wenjian , Zhang Jianxiu , Clegg Nigel , Guo Chengfeng 
Published: February 2025

Abstract
This paper focuses on the optimization of well placement in the unconsolidated reservoir H in the South China Sea. The reservoir, located at a burial depth of 1050m, consists of three sand units with high-density interlayers and vertical heterogeneity. The lateral distribution of the top sand unit is uncertain due to wave transform. To effectively develop the reservoir, it is crucial to optimize horizontal well placement to increase exposure length of high-quality sand and distance from the water contact. This can be achieved by enhancing understanding of lateral distribution and vertical properties during drilling.
A combination of high-definition multi-layer reservoir mapping technology and a hybrid point-the-bit rotary steerable system (RSS) was introduced for the first time in the South China Sea. The reservoir mapping technology improved the ability to detect up to 10 layers and investigate depths up to 9 meters, providing visual display of sand unit distribution and the oil-water contact in this complex reservoir. The high dog-leg capability RSS navigated through larger hole sizes in unconsolidated sand, reducing the risk of borehole enlargement. An optimized hydraulic design with high drilling bit total flow area (TFA) and low flow rate bottom hole assembly (BHA) minimized borehole washout. These technologies allowed for real-time reservoir mapping data to be utilized in implementing and adjusting specific development strategies, ultimately improving reservoir productivity.
The well placement optimization involved implementing 7 horizontal wells in reservoir H with a total penetration of 2970 meters, achieving 100% contact rate in the high-quality reservoir. The oil water contact (OWC) was identified 8.3 meters below in the lower part of the structure, increasing the lifespan of the horizontal wells. In the middle part, the wells were placed in the high-quality sand layer, resulting in a reduction of remaining oil above. In the higher part, a stepped well path with proper distribution of the top two sand units increased production capacity by 30%. The total production of the project exceeded expectations by 10%. An anomalous, low resistance stripe was mapped along the well bore in the sweet zone, a mud invasion study found that was caused by the low resistivity mud filtrate rapidly formed a 1.2 m diameter flush zone in the stratum. The high-definition reservoir mapping results provided insight into the structure, allowing for modifications and improved understanding of lateral change in the formation.
The successful application of this integrated solution package confirms the feasibility of the integrated solution package in complex reservoirs with poor consolidation and provides valuable experience for future offshore oilfield applications.
Transforming Depleted Reservoirs - a Pioneering Subsurface Study for Offshore CCS
Authors: Yan Jia , Mansor Najmi , Azahan Fahim , Grace Amelia William , Szafranski Robert , Shamsul Hasif , Ling Evelyn 
Published: February 2025

Achieving global net-zero emissions by mid-century necessitates a variety of climate mitigation technologies, including carbon capture, utilization, and storage (CCUS) or carbon capture and storage (CCS). According to analyses by the Intergovernmental Panel on Climate Change (IPCC), the International Energy Agency (IEA) and other sources, CCS will be required as a part of a suite of mitigation strategies in order to meet emissions targets (Global CCS institute, 2023). This will require a significant expansion of CCS by mid-century, despite numerous challenges throughout its value chain. Identifying and developing suitable storage spaces and capacities are crucial, and dedicated programs are essential to evaluate and enhance these potential storage sites for CCS.
CCUS can be categorized into three main types: CO2 enhanced oil recovery (EOR), pure CO2 storage in saline reservoirs, and storage in depleted reservoirs. In CO2 EOR, CO2 is utilized, recycled, and reused to boost hydrocarbon production. Conversely, storage of CO2 in deep saline reservoirs or depleted oil and gas fields is a permanent storage solution that will help achieve global net-zero. However, there are currently fewer commercial-scale projects focused on these types of storage compared to CO2 EOR projects (Rubin E. et al. 2018).
Advanced subsurface geological and reservoir engineering studies indicate that there is substantial CO2 storage capacity globally, particularly in subsurface saline reservoirs. According to the IEA's 2021 estimates, the total global storage capacity ranges from 8,000 Gt to 55,000 Gt, primarily in saline reservoirs based on geospatial data from NGO databases. However, the economic viability of CCS projects is uncertain due to the lack of specific subsurface data, such as production data and geological characteristics, in regions outside hydrocarbon areas and saline wet reservoirs. Additionally, the limited surface infrastructure in these regions exacerbates this issue. This lack of data leads to uncertainty in key factors such as tank capacity and injectability, which in turn contributes to economic uncertainty for CCS projects.
Resilience in Well Operations Avoided a Workover: Best Practices and Lessons Learned for Well Revival and Obstruction Removal
Authors: Kalwar Ghulam Murtaza , Alomran Ali A , Raza M. , Coello P. Vandeweerd 
Published: February 2025

Abstract
Generally, obstructions in the completion string are removed with chemical and mechanical means, depending on their nature. When the nature of obstruction is obscure, the rules of thumb, best practices, and lessons learned from the past are consulted. During the coil tubing milling operations to mill the cement and plug post workover, obstructions were encountered above the sand screens restricting the wellbore accessibility and restoring the production. Instead of another work-over, a resilient engineering approach spanning different steps was adopted to overcome the obstruction. The best practices and the lessons learned in reviving the well are the subject of discussion in this paper.
Numerous techniques were adopted during the intervention operation to identify and bypass the nature of damage present downhole to access the sand screen. CT cleanout runs were devised but remained inconclusive in overcoming the downhole obstructions. Therefore, wellbore diagnostic was performed using downhole camera, which increased the understanding of actual downhole challenges. Based on the wellbore diagnosis, certain best practices and lesson learned were applied in subsequent cleanout / milling operation that allowed access to the sand screens and enabled removal of detritus which was obstructing hydrocarbon flow from the sand screens. The downhole tools and fluid selection played pivotal role in increasing the effectiveness of applied best practices.
A combination of through tubing wellbore diagnosis, cleanout, and milling applied with best field practices restored access to the wellbore's total depth (TD), re-establishing the well's flowing potential. Wellbore diagnosis provided visuals to enable better understanding of the actual conditions unaccounted for in the initial intervention operations. The presence of scale, ID reduction and sluggish material in front of screens required a customized intervention approach. Accordingly, cleanout and milling runs were devised with contingencies to tackle any unforeseen circumstances.
Wellbore diagnosis, cleanout, and milling are not novel and are frequently deployed in well- intervention operations. Nevertheless, the result of two operations under the same conditions differ due to the technicalities involved. The application of best practices and lessons learned, when combined with wellbore diagnosis, played a key role in the success of this operation. This paper will highlight those tools and techniques to reach a wider audience and avoid similar issues. Moreover, areas of further improvement and novel means of achieving "more with less" shall also be discussed for continuous improvement of intervention operations.
Multi-Scale Fracture Prediction and Modeling
Authors: Liu Zhaolong , Zhang Yongzhong , Wu Jin , Zhang Lei , Feng Deng , Zhou Peng , Ge Qiang , Song Mingzhe 
Published: February 2025

Abstract
Fractured reservoir is one of the critical reservoir types, and the accurate characterization and prediction of fractures are essential for the high-efficiency development of oil fields. Due to the complexity and multiple solutions, fractures pose significant challenges to quantitative predictions. By integrating outcrop, seismic and core research methods, this paper analyze fracture characteristics such as length, strike and aperture, to determine the genesis, scale, and period of multi-scale fractures. Subsequently, we employ the finite element numerical simulation method to build a geomechanics model, which can be used to quantitatively simulate the aperture, density, and other parameters of fractures. Additionally, statistical methods are employed to provide a quantitative description of formation, fault, and fracture parameters. A multi-scale discrete fracture network model is then constructed using single-well fracture data, while considering multiple constraints such as geomechanics, curvature, and distance to fault. The geomechanics-based multi-scale fracture modeling method simulates fracture development under various conditions and constraints, considering fracture genesis from a comprehensive perspective. This approach allows for more systematic identification of fractures and more accurate predictions, leading to improve prediction accuracy. The method provides valuable guidance for well deployment, optimizing gas recovery rates, and enhancing recovery. It also serves as a basis for later engineering modifications, and has significant research implications for the gas development.