bluuebunny/crossref_metadata_2025_split huggingface dataset:
Novel Advances in Under-Balanced Coiled Tubing Mechanical Descaling Operations Using Fiber Optic Real-Time Telemetry
Authors: Alaskar S. Y. , Waheed A. S. , Aljehairan O. H. , Azly A. A. , Alyami M. , Tapia W. , Naveed M. A. , Alsulays Ali 
Published: September 2024

Abstract
Downhole scale removal is known to be an uneasy task but removing scales in wells with sub-hydrostatic pressures puts it in a different league of challenges. Conventional descaling techniques fall short in sour wells due to cases of uncontrolled hydrogen sulfide (H2S) gas releases at surface, which is a major Health Safety and Environment (HSE) issue, topped with the inability to maintain fluid circulation which causes formation leak off and inevitably induced reservoir damage. This paper discusses under-balanced coiled tubing intervention of live wells for descaling operations.
The descaling technology has evolved on the backs of the recent advances made in real-time downhole monitoring capabilities using fiber optics. This system includes a bottom-hole assembly (BHA) with a full array of real-time sensors (pressure, temperature, casing collar locator, gamma ray, load measurements), and powerful wellbore cleaning tools that can penetrate and remove hard scale deposits. These BHAs’ are designed to withstand high level of shocks and vibrations with bottom-hole temperatures exceeding 300°F. Assisting the fiber-optic telemetry is a fluid hydraulics simulation software that accounts for solids (i.e. scales removed) loading in the fluid stream in equivalent circulating density (ECD) calculations and maintaining a predetermined underbalance condition throughout the descaling process. Since there is high chance for H2S leakage on surface in an underbalanced, flowing well condition, it becomes essential to have a gas-tight, error-free well testing equipment package deployed to meet this challenge.
Presented in this paper is a detailed account of the operational planning, risk assessment, and execution of the underbalanced CT descaling operation. The under-balanced approach proved instrumental in restoring wellbore accessibility and productivity, surpassing the limitations of conventional acid de-scaling methods. Comparisons between conventional descaling and the under-balanced operation highlight the advantages of the latter, including improved efficiency, cost savings exceeding 20%, a 30% production gain, and full restoration of well accessibility. The under-balanced method showcases its adaptability in addressing challenges posed by hard scale accumulations, demonstrating its superiority over conventional techniques. This paper contributes valuable insights into the evolution of descaling interventions techniques, showcasing the success of under-balanced operations as a transformative approach in the realm of live descaling methods. The comparative analysis provides a comprehensive understanding of the operational efficiencies and benefits associated with adopting innovative under-balanced techniques for well interventions.
Drilling Fluid Design for Safe, Efficient Resource Delineation in XHT Geothermal Reservoirs
Authors: Bageri Mohammed , Cascone Alessandro , Vordick Travis 
Published: September 2024

Abstract
The development of advanced drilling fluids capable of withstanding Enhanced Heat Transfer (XHT) conditions in geothermal reservoirs is critical for the safe and efficient exploration and production of geothermal resources. This study presents innovative fluid formulations designed to enhance drilling performance in XHT geothermal reservoirs. The research addresses challenges such as fluid stability, formation integrity, and effective lost circulation control. The primary objective is to develop and validate drilling fluids that maintain stability and performance at extreme temperatures, specifically in supercritical geothermal environments.
Laboratory tests and field applications validated the performance of these advanced drilling fluids. The methodology included the selection of base fluids, viscosifiers, and additives through a Traffic Light Analysis (TLA) approach. Key components identified were High-Temperature Stabilizer and Thermal Enhancer, due to their thermal stability and mechanical properties. The fluid's performance was further enhanced through polymer temperature extenders and advanced fluid loss control additives. High-Temperature High-Pressure (HTHP) viscosity measurements and Scanning Electron Microscope (SEM) analyses assessed the fluid's rheological properties and microstructural characteristics.
Results demonstrated that the new formulations-maintained viscosity and stability at temperatures up to 800°F, significantly outperforming traditional fluids that typically degrade at 400°F. Field trials, including the Iceland and Italy, confirmed the formulations’ effectiveness. These trials recorded improved fluid stability, with the Geothermal Specific Fluid (GSF) system maintaining a plastic viscosity (PV) of 9.9 cP and yield point (YP) of 39.8 lb/100ft2 at 120°F, which remained stable after aging at 706°F for 96 hours.
These advancements highlight the potential for these advanced drilling fluids to revolutionize geothermal drilling, making it more effective, economical, and environmentally friendly. The GSF system's ability to maintain stability and performance at extreme temperatures, improve fluid loss control and potentially reduce the risk of non-productive time related to fluid quality represents a significant leap forward in geothermal drilling technology. This approach not only meets the immediate needs of geothermal drilling but also provides a robust and efficient solution that significantly enhances operational performance and cost-effectiveness.
A Field Application of Machine Learning for Sonic Log Prediction and In-Situ Stress Estimation in Natural Buttes, Uinta Basin, Utah
Authors: Kim Changjae , Morales Adrian , Oberg Darin , Black Brooks 
Published: September 2024

Abstract
It is necessary to use sonic logs in gathering rock mechanical properties which are used to estimate in-situ stresses which are useful for fracture design and reservoir characterization. However, the high cost of its acquisition deters companies from getting complete well measurements and in some cases, we may have incomplete sonic log data due to tool damage, poor calibration, and other reasons. In other cases, the well of interest might only have a triple combo suite to determine target depths and left up to engineering judgment what a hydraulic fracture might look like.
This study shows a field application of machine learning (ML) algorithms using triple combo logs to predict elastic properties and finally estimate in-situ stress profile in the Natural Buttes gas field. We used a complete set of triple combo and dipole sonic logs to train K-Nearest Neighbors (KNN) regression and Bi-directional convolutional long short-term memory (Bi-ConvLSTM) models. A data preparation and transformation technique were applied to reduce heteroscedasticity by manipulating data distribution. Then, prediction-performances were compared to each other, and a selected ML model went through a validation to verify it effectively captures existing patterns in the well log data. The selected ML model was finally deployed into a GUI interface which is helpful for users to create predictions, visualize and analyze the generated results.
Comparative analysis of ML models shows that the KNN mitigates overprediction observed in the Bi-ConvLSTM. The KNN reduces training time while the Bi-ConvLSTM is computationally expensive as it considers well log data as an image. We also quantify uncertainty of KNN predictions through a heuristic approach to provide uncertainty thresholds as decision boundary for in-situ stress estimation. For calibration verification, we present one data set showing the predicted sonic velocities vs actual measured velocities as well as the predicted vs actual elastic and in-situ stress profile. The GUI can deploy trained models, take test data for prediction, visualize triple combo logs, predicted sonic logs, calculated elastic properties and in-situ stresses with variances for analysis. We conducted fracture modeling using a commercial numerical simulation tool for both the measured and synthetic cases and found the SRV was similar to each other.
This study demonstrates that the use of machine learning combined with well-established data transformation, uncertainty estimation, and visualization can reduce time and cost in extracting and analyzing a valuable information. Based on literature review, this is the first time that such a workflow has been shown up to the in-situ stresses portion of the workflow. We finally, perform hydraulic fracture simulation on the synthetic in-situ stress profile case and show equivalent results to the calibrated in-situ stress profile case.
Reassessing Free Water API Testing Procedure
Authors: Mahmoud Ahmed Abdulhamid 
Published: September 2024

Abstract
Accurate determination of the top of cement is critical for the success of oil well cementing operations. The American Petroleum Institute (API) free water test is a standard procedure designed to assess the free water content in cement slurries. However, this study reveals significant limitations in the API free water testing procedure, particularly for cement slurries with very low density achieved by adding more water than recommended by API guidelines. Investigation involved comparing the results of the API free water test, which is conducted over a 2 hours period, with an extended 24 hours test. The findings indicate that for the low-density slurries, the 24 hours samples exhibited a considerably higher amount of free water compared to the 2 hours API test results. This increased free water presence significantly reduces the height of the cement column, which is not accurately captured by the standard API procedure. These discrepancies highlight the inadequacy of the current API free water test for low-density cement slurries and underscore the necessity for reassessing and potentially modifying the testing standards to ensure accurate top of cement. This study provides a critical evaluation of the API free water test, emphasizing the importance of longer testing durations for the lightweight slurries to capture true free water content and suggesting improvements for more reliable and effective well cementing operations.
Incorporating Self-Degradable Fibers into High Performance High Strength Particulates to Combat Losses While Drilling Across Reservoir Section in Extended Reach Well in Middle East Field
Authors: Bamiduro Abayomi , Peres-Demarthon Guillaume , Phyoe Thein Zaw , Pallapothu Surya , Pauferro Paulo , Aghaguluyev Javid 
Published: September 2024

Abstract
Lost circulation on drilling wells within the fractured limestone reservoir results in a significant loss of time when treating the losses. Furthermore, lost circulation can be detrimental to well productivity due to the damage caused by the influx of lost circulation material (LCM) into reservoir sections. Drilling fluid in these sections is replaced with sea water to mitigate formation damage and to reduce the hydrostatic pressure of the fluid column at the loss zone. Despite using sea water, total losses are typically encountered in these sections. Several conventional LCMs, fibrous and cementitious LCMs have historically been used to mitigate these losses. However, these LCMs could potentially reduce future well productivity and tend to plug surface facilities / equipment during production. Therefore, the application of an effective LCM that would cure the losses while minimizing the formation damage is required.
A novel self-degradable fiber-based pill with acid soluble particulates specifically designed to cure losses in the reservoir section. Once placed, the pill forms an impermeable plug inside a fracture that is stable until the completion of the well. Based upon wellbore temperature and pressure, the fibers will self-degrade to prevent any long-term formation damage in the reservoir section that could impact future production. Laboratory tests indicated that a plug formed from the pill seals a fracture width up to 10-mm and withstand differential pressure as high as 1000 psi. The tailored pill design allows for complete self-degradation of fibers and particulate can exhibit solubility with the presence of acid following downhole placement of the pill. This pill was designed to be pumped through either a dummy bottomhole assembly (BHA), through bypass circulation ports above the BHA or an open-ended drill pipe.
The self-degradable fiber-based pill with bridging particles was successfully pumped across the 8 ½-in reservoir sections. The plug was placed through bypass circulation ports by spotting the pill above the loss zone. Following treatment, the loss rate was effectively reduced by more than 95% allowing drilling to continue with drilling operations and without any major impact on future well productivity. The self-degradable pill was used for multiple loss circulation treatments with similar results.
Deploying the pill at a different depth proved its applicability under different conditions developing into a standard engineered approach for curing losses in reservoir section. Incorporating fiber with degradable property and bridging materials proved the effectiveness of the novel self-degradable fiber to mitigate losses across reservoir zones in Middle East.
Advancing Proxy Modeling in Reservoir Simulation: A Multi-Step Embed to Control Approach
Authors: Chen Jungang , Gidlin Eduardo , Killough John 
Published: September 2024

Abstract
Reduced-order models, also known as proxy model or surrogate model, are approximate models that are less computational expensive as opposed to fully descriptive models. With the integration of machine learning, these models have garnered increasing research interests recently. However, many existing reduced-order modeling methods, such as embed to control (E2C) and embed to control and observe (E2CO), fall short in long-term predictions due to the accumulation of prediction errors over time. This issue arises partly from the one-step prediction framework inherent in E2C and E2CO architectures. This paper introduces a deep learning-based surrogate model, referred as multi-step embed-to-control model, for the construction of proxy models with improved long-term prediction performance. Unlike E2C and E2CO, the proposed network considers multiple forward transitions in the latent space at a time using Koopman operator, allowing the model to incorporate a sequence of state snapshots during training phrases. Additionally, the loss function of this novel approach has been redesigned to accommodate these multiple transitions and to respect the underlying physical principles. To validate the efficacy of the proposed method, the developed framework was implemented within two-phase (oil and water) reservoir model under a waterflooding scheme. Comparative analysis demonstrate that the proposed model significantly outperforms the conventional E2C model in long-term simulation scenarios. Notably, there was a substantial reduction in temporal errors in the prediction of saturation profiles and a decent improvement in pressure forecasting accuracy.
Investigating Dielectric Property from LWD Propagation Measurements a Modeling Study
Authors: Zhang J. , Ma S. , Al-Ofi S. 
Published: September 2024

Abstract
Formation dielectric property that is highly affected by formation fluid saturation can be an additional physical parameter for geo-steering in low resistivity pay (LRP) formations. Unlike wireline dielectric tools, LWD propagation tools operate at much lower frequencies where formation dielectric constant estimation is challenging. Thus, the sensitivity of dielectric properties for different tool's operational parameters should be investigated, as the main objective of this study.
In this paper, finite-element numerical modeling was validated and used to calculate the electromagnetic (EM) fields in a cylindrical borehole and homogenous isotropic formation. The EM propagation is governed by a set of antennas including a transmitter and two receivers geometrically modeled as in current LWD tools. During the sensitivity analysis, different operational parameters such as tool diameter, frequency, antenna spacing, borehole size, mud and formation properties were varied. Signal attenuation and phase shift across the two receivers were utilized in this study. The sensitivity of attenuation and phase shift were assessed against varying formation dielectric properties for each combination of operational parameters.
The accuracy of the numerical modeling results was validated against an established magnetic dipole solution. For a standard tool configuration and operational frequencies, i.e., 2 MHz, the sensitivity of formation dielectric constant on simulated attenuation and phase shift increases rapidly as formation resistivity is higher than 100 ohmm and dielectric constant is higher than 20. Also, the higher the frequency the better the sensitivity to the formation dielectric property. When the frequency is higher than 10 MHz, the measurement sensitivity to the formation dielectric constant is dramatically improved and thus makes it applicable for well placement in the low resistivity LRP formations. Results also indicate that the shorter Tx spacing may help the dielectric constant sensitivity but mainly improve the signal-to-noise ratio. Meanwhile, the Rx spacing does not influence the dielectric constant sensitivity significantly.
The findings of this study further confirm our recent study (Al-Ofi et al., 2024) and open a path for advanced geosteering in complex drilling conditions where some bottom-hole assembly may be limited and restricted such as in a slim hole under balanced coil tubing drilling, or when other LWD sensors cannot perform effectively.
CCUS Well Integrity Success Using Fit-for-Purpose Cement Designs
Authors: Shine J. M. , Sowailem A. W. , Bechah Z. , Qasmi U. K. 
Published: September 2024

Abstract
Defining long-term zonal isolation requirements for any carbon capture underground storage (CCUS) project life cycle is important to support well integrity success. The utility and scope of an underground storage project helps guide the isolation requirements for the well construction phase emphasizing the well design and cementing. Within the domain of cementing, a basis of design approach holistically can evaluate the corrosive risks, isolation requirements, cement installation, and degree of integrity for the anticipated well utility or load cases. The manuscript highlights the results of a field deployed and validated cement design being able to withstand CO2 corrosive exposure helping to achieve zonal isolation for CCUS well construction while managing the anticipated load conditions to ensure wellbore integrity. Several case histories, a 6-month corrosive study performance analysis, and cement integrity modeling support the fit-for-purpose designs helping to deliver well integrity success.
Implementation of Petroleum Industry Act 2021 - A Pathway for Economic Prosperity and Sustainable Development in Nigeria
Authors: Nwankwo O. K. , Ringim A. U. 
Published: September 2024

Abstract
The enactment of the Petroleum Industry Act 2021 (PIA) reformed the Nigerian petroleum industry from a single regulatory framework that was in effect for over 50 years to a dual regime, by introducing clear distinctions between the streams of petroleum operations that was previously not clear-cut and the creation of two distinct and focused regulators for the upstream value chain and for the midstream and downstream. The objective of this paper is to review the PIA Best-In-Class Regulatory Framework for achieving a path to economic prosperity and sustainable development in Nigeria. Furthermore, the lesson learnt and experiences from introducing a new approach and transitioning from a single to a dual regulatory regime was also reviewed. The objectives of this paper were achieved through the comprehensive review of the updated regulatory structures, general administration and functions of the regulators that provides clear focus for industry stakeholders for investments opportunities and benefitting from the reforms of the PIA. Additionally, comparisons of the provisions of the Petroleum Act of 1969 to the PIA, the change programs of the PIA Transition committee, the scope of work and terms of reference of consultants saddled with handling some change management programs and the industry and regulators responses to the introduction of a new approach was also studied. The paper found that the PIA addressed the operational deficiencies of the previous regulatory regime by the recognition of distinct streams on the petroleum value chain established through custody transfer, provided clear focus for the regulators and industry stakeholders in the light of energy transition, unbundled the licensing system that hitherto exist, and entrenched transparency in hydrocarbon accounting. Therefore, the implementation guarantees Nigeria optimized value chain, energy security, improved government revenue, expansion of industry for employment. However, despite the clear benefits, change management related to strategic communications, trainings and transition of industry experience from previous regulatory framework is a big factor to prevent regulatory uncertainty. Recognition of distinct streams for value chain optimization offers advantages and provides pathway for economic benefit and sustainable development. Lastly, the paper finds and recommends that any regulatory transitioning, effective implementation of new approaches and attainment of objectives and benefits of such reforms must be accompanied by detailed change management program.