bluuebunny/crossref_metadata_2025 huggingface dataset:
Inner Wear Liner for Top Tensioned Riser Sidetrack Drilling Operations
Authors: Sundararaman S. , Stiel B. , Thethi R. , Guglielmo C.
Published: April 2024

To increase well productivity, sidetrack drilling operations can be conducted through existing production top-tensioned risers (TTRs). Since 2014, Eni Petroleum have successfully conducted plug back, sidetrack, and recompletion of three wells at the Devil's Tower spar platform in offshore Gulf of Mexico. The platform has eight TTRs with subsea wellheads, which were subsequently tied back to the spar and completed in surface wellheads with dry trees.

This paper presents the riser system design, challenges and the results from the pre-drill dynamic riser analysis and post-drill riser monitoring assessment due to environmental, vessel, and operational loads. This paper also addresses the key benefits and challenges involving the use of a temporary wear liner through the existing spar top tensioned riser system while working within the available aircan tension capacity and dimensional clearance through the riser pipe.

Dynamic global riser analysis is conducted to ensure that there is adequate strength capacity with the wear liner in place. Furthermore, the riser system should tolerate loss of buoyancy through a flooded compartment in the aircan and a shut-in scenario where the drill string is supported by the surface BOP. Results from wear and fatigue damage due to vortex induced vibrations (VIV), vessel induced motion (VIM), drilling induced vibrations (DIV) and wave induced motions are presented based on design motions and monitoring data.
Design, Fabrication, Simulation, and Initial Testing of an Unmanned Surface Vehicle for Oil Spill Sampling
Authors: Ramos R. , Li H. , Olson I. , Diagne L. , Gutierrez D. , Mower R. , Earwood J. , Mendoza M. , Garcia-Pineda O.
Published: April 2024

Detection of oil spills with aerial or space-born remote sensing resources has been deeply studied and developed over recent years. However, all these technologies still rely on in-situ verification with direct monitoring and sampling for validation. This paper presents the design, fabrication, simulation, and testing of an unmanned surface vehicle (USV), specifically designed for hydrodynamic efficiency and effective oil spill sampling. The USV's design, featuring a customized platform for the oil sampling mechanism, underwent an extensive simulation process using computational fluid dynamics (CFD) to validate its stability and analyze its impact on water flow dynamics. The design and fabrication process involved hull construction, integration of the control and power systems, and testing in a laboratory environment. The CFD analysis and testing revealed exceptional stability in the USV, showing only minimal rocking and pitching, which translates to consistent speed and precise navigation for the USV during operation. Using CFD for the design analysis allowed for the optimization of water flow dynamics between the two hulls, resulting in reduced drag and enhanced maneuverability for the USV. Turbulent flow patterns were observed at higher speeds, which notably provided valuable insights into the USV's hydrodynamic behavior and its possible interaction with any unforeseen marine conditions, such as encounters with marine life or debris. The key findings demonstrate the USV's potential to revolutionize environmental response efforts, especially in the context of oil spill disasters in remote areas. The accuracy of the CFD simulations was pivotal in anticipating the USV's performance in various marine conditions, which demonstrates the importance of collaboration between theoretical models and practical applications. This paper introduces an innovative integration between autonomous technology and environmental responsiveness, which showcases the possibilities of advancements in the field of autonomous maritime solutions. The involvement of this research extends beyond its immediate scope and offers a new prototype for monitoring and protecting marine environments. This advancement significantly contributes to the broader discussion for safer, more sustainable offshore exploration and environmental management.
Mechanical Seal Integrity for Geological Storage of CO2
Authors: Ait Ettajer T. , Ibañez Martinez E. , Alvarellos Iglesias J. , Rodriguez Morillas N. , Martin Rodriguez H. , Martin Carrillo M. , Mora S. , Vayssaire A.
Published: April 2024

The geological storage of CO2 was identified, by the International Energy Agency (IEA) as one of the key levers for meeting the target of carbon neutrality in 2050 (IEA 2022). The main pillars of the value chain of the geological storage are: 1. Capacity, 2. Containment, 3.Transport and Injectivity, 4. Monitoring and Remediation, and 5. Stakeholders Management. Although the first pillar is key as it defines the range of volumes of CO2 that can be stored, the regulatory framework requires that the injected CO2 must remain permanently underground, and that the activity of the CO2 injection does not trigger any induced seismicity (US Department of Energy 2021).
An Application of Machine Learning to Predicting Shear Wave Velocity of Marine Clay
Authors: Taboada V. M. , Sanchez-Hernandez Y. , Zhang Z. , Cruz Roque D. , Barrera Nabor P. , Gan K. C.
Published: April 2024

In geotechnical earthquake engineering, shear wave velocity (VS) is one of the most important parameters. Several empirical correlations have been developed to estimate VS based on in situ tests, such as P-S logging tests and piezocone penetration tests (PCPTs), and soil properties determined both offshore in a field laboratory and onshore in a geotechnical laboratory. Recently, artificial intelligence (AI), machine learning, and deep learning have been the subject of intense media hype and therefore it was deemed appropriate to develop a deep-learning algorithm (DLA) to predict VS and compare its performance with conventional empirical methods of determining VS. A database of 11 sites in the Bay of Campeche with in situ measurements of VS using P-S logging and 8 clay soil parameters, including in situ measurements of net cone resistance (qnet), water content (w), submerged unit weight (g’), void ratio (eo), undrained shear strength (su), effective overburden pressure (σ′vo), over consolidation ratio (OCR), and plasticity index (Ip), was used to train a DLA and develop empirical equations based on multiple regression analysis (MRA) to predict VS. The accuracy of the results (i.e., how close the predicted VS values are to the in situ measured VS values) illustrates the great potential DLA has to become another class of computational tool to predict VS, and DLA has the advantage that it can be continuously updated as new data become available. The DLA was found to outperform MRA when the three input variables are measurements of qnet, w, and σ′vo and when the eight clay soil parameters are used as input parameters. The results suggest deep learning has the potential to overcome prediction limitations associated with linear or polynomial trends and adjust to discrete variabilities in soil conditions. They also reveal potential applications for deep learning in reducing uncertainty in the characterization of areas with complex soils without drastically increasing the scope of a site investigation.
Monitoring of Drilling Fluids and Cuttings as an Environmental Management Tool for Offshore Fluid Operations
Authors: Marinho L. S. , Pereira B. C. , Guandalim F. P. , Cavalcante L. M.
Published: April 2024

This study aims to present the comprehensive outcomes of drilling fluids and cuttings monitoring conducted in the Santos Basin, Brazil, during drilling operations. The research sheds light on the environmental implications and management strategies related to offshore drilling activities. These insights can support decisions guided by Life Cycle Assessment (LCA), aiding in informed choices to enhance efficiency and sustainability. The drilling fluids and cuttings monitoring project (DFCMP) encompasses data on drilling discharged into the sea. The monitoring took place during the drilling of 41 deep water wells in Santos Basin, Brazil. Samples were collected at various stages of drilling operations. Data includes discharge quantities, ecotoxicological profiles of the fluids, as well as determinations of metals and polycyclic aromatic hydrocarbons (PAHs) in the samples. These methods enabled the evaluation of environmental impacts throughout the drilling lifecycle. This comprehensive approach provides valuable insights into the effects of drilling activities, contributing to informed decision-making in line with Life Cycle Assessment principles. The monitoring of fluids and cuttings discharged into the sea from 41 drilling operations carried out between 2022 and 2023 in the Santos Basin, Brazil, generated representative samples of fluids and cuttings. These samples account for the offshore discharge of 16000 m³ of cuttings and apporximately142000 m³ of aqueous fluids. Chemical and ecotoxicological analyses conducted on these samples confirm the environmental compliance and quality of these discharges, affirming their adherence to the legal requirements established in Brazil. Regarding the waste generated for onshore disposal, the compiled results indicate an average annual generation of around1590 tonnes of waste, with about 56 % comprising liquid waste from fluid operations, primarily aqueous fluids. Despite fluid and cuttings characterization being present in scientific literature, few contributions emphasize samples collected prior to sea discharge. Many characterizations focus on terrestrial disposal routes and cater to relevant criteria for this purpose. Our study's findings enhance understanding of qualified fluid and cuttings discharged at sea, highlighting industry best practices that meet Brazilian regulations. These locally relevant data are crucial for life cycle analysis, aiding environmental profiles and impact assessment for different waste management routes.
Risk Mitigation for Punch through of XXL Monopiles – MPM Validation and Field Observations
Authors: Thijssen R. , Martinelli M. , Luger D.
Published: April 2024

Uncontrolled punch through during set down of an XXL monopile can be disastrous for a (floating) installation vessel. An analytical model was developed to predict punch through capacity for monopiles on sand-over-clay conditions. Material Point Method (MPM) analyses were used for validation of the model and a proposed risk mitigating measure that allows for a controlled punch through, with reduced risk to vessel and equipment. Field observations from construction of a wind farm off the US East coast allowed for full scale validation of the model and reflect the effectiveness of the risk mitigating measures taken.
Quantifying the Mechanical Specific Energy (MSE) with Differential Wellbore Pressure for Real-Time Well Automation
Authors: Sahood Tariq , Myers Michael T. , Hathon Lori , Unomah Gabriel C.
Published: April 2024

Drilling efficiency is the ratio of unconfined compressive strength (UCS) to mechanical specific energy (MSE); this parameter is important for understanding the drilling process and essential for attempts at drilling automation. MSE is a measure of the energy required to remove a unit volume of rock and depends on many parameters, including the rate of penetration (ROP). However, the standard use of MSE is limited in optimizing drilling efficiency because it fails to account for the effect of wellbore differential pressure (wellbore pressure minus pore pressure) on ROP.

UCS has an obvious influence on drilling efficiency, but it is difficult and expensive to measure UCS values under differential pressure. To eliminate the need for measurement of UCS, we applied a modified MSE (MMSE), which accounts for the effect of differential pressure. This is performed by multiplying the MSE by the ratio of pore pressure to bottom hole pressure. Bottom hole pressure is calculated from the mud weight and well depth and corrected for frictional losses. The pore pressure is calculated using the hydrostatic gradient.

We overlaid resistivity logs from eight wells, which are sensitive to pore pressure, and compared the trends of MSE and MMSE. The MMSE shows better correlations with resistivity data, especially in over-pressured reservoirs, which results in a more accurate prediction of drilling efficiency. In normal pressured zones, the MMSE and MSE values show similar trends. As expected, they deviate from the typical compaction trend lines for the over-pressured zones. The depth and pore pressure data in the over-pressured zones are typically obtained from the drilling record. A higher correlation between MMSE and the resistivity log data occurs in overpressured intervals.

The comparison between MSE and MMSE was also tested on historical well data. The calculated MMSE again closely correlates with the resistivity. Therefore, MMSE is expected to predict abnormal pore pressures (overpressure) using the degree of divergence of the MMSE from the MSE values. Also, during underbalanced conditions or indicating a potential kick, the value of the MMSE is less than one. This predicts a large rate of penetration (ROP) and potentially gives an improved method of predicting a kick. In general, the MMSE significantly improves the understanding of drilling rates and pore pressure prediction.
Real-Time Automated Drilling Optimization with Digital Twins: Enhancing Performance, Mitigating Risks, and Reducing Costs
Authors: Cao Jie , Gocmen Emre , Nabavi Josef , Oedegaard Sven Inge , Kristiansen Tron Golder , Khosravanian Rasool , Solem Kristian
Published: April 2024

This paper presents an innovative approach to digital and automated drilling, offering cost reduction, improved development efficiency, and enhanced risk management. The focal point is an automated Rate of Penetration (ROP) optimization system powered by digital twin and artificial intelligence (AI) technologies, which effectively enhances drilling performance while mitigating potential issues.

At the core of this system are digital twin transient models, continuously calibrated using real-time data, and a fast auto-optimization module. Leveraging model-based reasoning in AI, the system provides real-time, forward-looking advice on operational parameters. It incorporates predictive analytics and multiple what-if scenarios to optimize drilling operations while considering imminent risks and anticipated hole-cleaning requirements for ROP optimization.

The effectiveness of the advisory system has been rigorously tested and verified, with a specific focus on the auto-calibration and auto-optimization modules. In this research, the system calculates time savings for each drilling section by comparing real-time ROP with advised values. The results clearly demonstrate the value created through reduced drilling time, empowering the rig team to operate independently and minimizing reliance on back-office support. Moreover, the system evaluates the potential drilling risks and hole cleanness for proposed operational parameters, ensuring the optimized results are risk-free in pursuing higher ROP.

Overall, this real-time optimization system offers a transformative approach to drilling operations, yielding significant time and cost reductions. Its supervisory capabilities streamline the implementation of advanced digital twin models and parameter optimization, thereby improving operational performance and driving further integrated drilling automation.
Pseudo 3D UMASW For Offshore Windfarm Development
Authors: Unterseh S. , McArthur L. , Mouton E.
Published: April 2024

In the frame of a Research and Development (R&D) project dedicated to quantitative ground modelling, Underwater Multichannel Analysis Surface Waves (UMASW) data were acquired within an offshore windfarm area currently in development in North Sea. The ultimate goal of the project described in this paper was to test the added value of the shear wave velocity (Vs) interpreted from the UMASW, particularly as a propagation tool of the geotechnical information. This requires a suitable Vs dataset within the foundation depth and the quantification of the associated uncertainties. The Vs of the ground is generally accessed in one dimension (1D) through geotechnical borehole (P-S-Primary & Shear seismic wave- logging or laboratory sample testing) or through S-CPT (Seismic Cone Penetration Test) in-situ testing within the offshore wind industry. The present acquisition was then an opportunity to compare both UMASW and borehole results, and to assess the spatial variability of the Vs around the boreholes.

The UMASW acquisition was designed to allow a pseudo three-dimensional (3D) gridding of the data, with a 10m bin size, and to reach a minimal signal penetration depth of 60m below seabed (bsb), compatible with the geotechnical investigation. Two block areas of about 400m × 300m, each centered around a borehole location, have been investigated together with a corridor area of 2300m × 20m tying the blocks. The spread used for the acquisition includes a sledge equipped with a 60cu.in airgun and a 166m long streamer with 48 channels. The sledge, dragged on the seabed, was tracked along intended 10m spaced lines with a shot point interval of 10m. The data processing was done for each shot and includes the manual picking of the dispersive curves and a 1D inversion modelling. The pseudo 3D gridding was then carried out by interpolation with the closest neighbors.

The results are found to be of good quality, with clear dispersive curves and a signal penetration reaching about 80m bsb. The standard deviation of the processed Vs remains generally below 3%. A first comparison of the Vs with the existing 2D Ultra High Resolution Seismic (UHRS) reflection data shows a good stratigraphic match with the key seismic horizons, while detailing some significant variability across the corresponding units. While UMASW, together with seismic refraction, is regularly used to characterize the ground for burial or trenching purpose, it appears to also bring valuable design parameters for the offshore wind turbine foundations.
Setting the Stage for a Novel Mooring Chain Integrity and Design Assessment Practice: The Partial SCF and Hot-Spot S-N Curve Approach
Authors: Nair A. , Dhaigude M. , Yao A. , Chen Y. , Jaiswal V. , Shavandi M.
Published: April 2024

Mooring chain's integrity is vital for offshore floating production units since their function ensures the required station keeping ability of the unit and protects the unit and associated critical assets such as risers. The decision of when to keep or replace a corroded chain is important for operators in the offshore oil and gas industry. While this topic has been a subject of several studies, actual fatigue consumption of a mooring chain due to corrosion, in-service loads and predicting the remaining fatigue life of the same chain in permanent floating structures remains a challenge. Incidents of premature mooring line failure has raised concerns on validity of mooring chain reliability in Industry Standards. This paper investigates the probability of failure of mooring chains based on available failure statistics, and its implication on current design and life extension practice. A partial SCF approach is proposed to assess fatigue life of corroded mooring chains. The approach was developed and validated through Fatigue of Corroded Chains (FoCCs) Joint Industry Project (JIP). In addition to the FoCC JIP validation, this paper presents application of the proposed approach on two recent corroded chain fatigue tests to predict its cycles to failure without FEA assessments.
High Temperature Compatible, Field-Deployable Heat Exchanger Nanocomposite Treatments
Authors: Uttley Katherine , Galvan Anika , Nakatsuka Matthew , Basile Marco
Published: April 2024

Fouling of refinery reboilers is a major source of production loss, health, safety, and environment (HSE) issues, and increased carbon emissions. Reboilers can be especially difficult, as fouling is difficult to address without major cleaning operations, and anti-fouling solutions outside of design modifications are limited.

Formulation development of a novel coating material for reboiler systems examined a wide variety of polymer and nanocomposite chemistries. An iterative development process was used to identify and synthesize a polymer nanocomposite surface treatment to protect against corrosion induced by the buildup of chloride and sulfide salts typically found within distillation reboilers. Application on carbon steel test panels was completed using industry standard spray application methods and subsequently characterized for adhesion strength, thermal stability, chemical compatibility, and corrosion mitigation.

Data included in this study will demonstrate that the material has a durability comparable to existing state-of-the-art coating materials (following ASTM D3359), chemical resistance to high acid and base solutions, and corrosion resistance (following ASTM B117) to support the long-term use of this novel surface treatment to protect metallic surfaces in harsh process conditions. Use of this novel material, compatible up to 350°C, has suggested the overall lifetime of the candidate reboiler system could be increased 2-fold based on previous applications of similar materials in field deployment.

This non-fluorinated, highly chemically resistant surface treatment can offer significant cost avoidance through the improvement of operational uptime and reduced maintenance costs in heat transfer applications typically susceptible to corrosion and fouling.
Intelligent Optimization of Ultra-Deepwater Oil Transmission Risers Using an Enhanced Graph Neural Network
Authors: Zhu Hong , Yang Jin , Xue Rui , Dai Shenghui , Zhan Shibo , Li Gengchen
Published: April 2024

With the continuous global demand for oil and advances in deepwater drilling technology, the development of deepwater oil and gas resources has become increasingly important. Steel catenary risers play a crucial role in connecting subsea and surface facilities. However, complex marine conditions in ultra-deepwater environments pose significant challenges to the design of SCRs. To achieve efficient and reliable operation of SCRs under these extreme conditions, this study proposes an intelligent optimization design method based on enhanced Graph Neural Networks. Initially, considering the structural characteristics of the SCR dataset, graph data features comprising various nodes were constructed. Subsequently, an enhanced GNN model was obtained through cross-validation and Bayesian hyperparameter optimization, incorporating Graph Attention Networks with pooling layers, which achieved exceptional results in predicting dynamic responses of SCRs. Utilizing this model, multi-objective intelligent optimization of SCRs in the South China Sea region was conducted, and the optimization effects were validated through simulation. The results show a reduction of 26.76% in maximum top tension and 24.15% in Max Von Mises at the touchdown point, with wave-induced fatigue life and vortex-induced motion fatigue life improved by 24.31% and 63.16%, respectively.

This research demonstrates that enhanced GNNs can efficiently learn the data relationships between different node features of SCRs and realize their effective optimization under extreme marine conditions, offering a reliable optimization design solution for ultra-deepwater oil and gas resource development. This approach opens new avenues for the optimization design of other marine structures.
Reducing Time-Lapse Seismic Data Acquisition Cost with Deep Learning
Authors: Hu W. , Phan S. , Li C. , Abubakar A.
Published: April 2024

Time-lapse (4D) seismic is one of the most important tools for monitoring of subsurface reservoir production. However, repeated monitoring data is time-consuming and expensive. To reduce monitoring data acquisition cost and the subsequent 4D data processing, we developed three novel deep learning powered algorithms to solve challenging problems including sparse monitoring seismic data reconstruction, simultaneous source shooting monitoring data deblending, and rapid subsurface property estimation directly from very sparse pre-migration seismic data. These algorithms exploit the subsurface information buried in the baseline data and then transfer the learned knowledge to the monitoring data, which narrows down the sampling space of deep learning network to circumvent the network generalization challenge for optimal network inferencing. Customized network architectures and special learning strategies were designed to overcome specific challenges in each individual application. For sparse data reconstruction, we adopted a self-supervised learning approach combined with two-pass learning workflow to improve computation efficiency. A two-stage network was developed to enhance the deblending accuracy while preventing the non-uniqueness issue. A unique deep learning method was proposed to estimate the subsurface property change due to production or other activities such as CO2 sequestration directly from a few pre-migration seismic gathers without being contaminated by strong artifacts that are often observed using conventional imaging or inversion algorithms to deal with sparse gathers. The numerical experiments demonstrated the accuracy and efficiency of these deep learning algorithms on both synthetic data and field data.
Process-Oriented Validation of HYCOM-TSIS Reanalysis Runs for the Northern Gulf of Mexico
Authors: Ivanov L. , Arena R. , Bozec A. , Chassignet E. , Longridge S. , Ramos R. , Srinivasan A. , Iskandarani M.
Published: April 2024

The Tendral Statistical Interpolation (T-SIS) package is used with HYCOM to produce the reanalysis hindcast. To assess 1/25° and 1/100° resolution model hindcasts’ performance, model results were compared to independent ADCP current measurements from several sites in the Northern GOM impacted by passing Loop Current Eddies, Deep Cyclonic Eddies (without a clear surface expression) and Tropical Storms. The comparative analysis of HYCOM-TSIS reanalysis data and ADCP measurements showed a good qualitative and satisfactory quantitative agreement between model and observations. Of most importance, the model with the T-SIS package resolves the general kinematic structure of subsurface flows associated with the Deep Cyclonic Eddies, reflecting a substantial improvement of the model skill compared to the previous version of the hindcast.
A comparison Study of the Mooring Simulation in the Design and Analysis of Floating Offshore Wind
Authors: Zhang F. , Wood C. , Wang Q. Q. , Nekstad O. J.
Published: April 2024

In wind turbine design, various critical aspects demand attention, including wind turbine design, assessment of floater structure, and optimization of the mooring system. Turbine designers prioritize control system optimization, relying on predicting responses like power generation and nacelle accelerations. Evaluating floater structure involves motion responses and loads on interface positions, like the tower base and mooring fairleads. The latter is crucial for positioning system optimization. These considerations often necessitate a comprehensive simulation of the entire system.

This paper conducts a comparative study of outputs of wind turbine, motion performances of the floater, and tensions of the mooring lines, involving various simulations using different mooring models, exploring both frequency and time domains. In the frequency domain, it begins with hydrodynamic analysis using equivalent springs and proceeds to a statistical analysis with a catenary mooring line model. Emphasizing time domain analysis, the paper extensively compares results from coupled analysis with a quasi-static catenary mooring model and a dynamic finite element mooring model. The wind turbine and floater models are kept identical, encompassing three power generation design load cases and two parked cases. The assumption is that the quasi-static approach can significantly reduce coupled analysis time, prompting an examination of its accuracy for the mentioned design focuses.

The conclusion reveals that, overall, the results for wind turbines and the tower—such as power generation, nacelle accelerations, and tower base moments—are very similar using two different mooring models in time domain analysis. Regarding floater motions, both approaches yield comparable results in the wave frequency range, but the quasi-static model tends to overpredict low-frequency responses. This conservative tendency affects global performance prediction more than structure assessment, as the latter mainly relies on wave frequency responses. Fairlead tension statistics show similar outcomes, but the power spectrum density indicates that the quasi-static mooring line may miss dynamic aspects. For capacity checks, the quasi-static approach remains valid, while it's recommended to use the dynamic FEM mooring line model for fatigue checks. A simplified approach may still be practical to streamline analysis for design iterations.
Geologic Considerations for Floating Offshore Wind, Gulf of Maine, USA
Authors: Rasmussen T. , Peralta P. , Fisher J.
Published: April 2024

The Bureau of Ocean Energy Management (BOEM) has designated call areas within the Gulf of Maine outer continental shelf in water depths suitable for floating turbines (i.e., greater than 100 m). The objective of this study is to present an overview of the geologic and geophysical conditions and constraints within the Gulf of Maine where potential lease areas may be located. This work expands on the previous 2022 BOEM-funded desktop study supporting the US Department of the Interior, Bureau of Safety and Environmental Enforcement’s solicitation for areas of interest to the Bureau of Ocean Energy Management Technology Assessment Program on offshore wind technology (BAA No: 140M0121R0006) (Fugro 2022).

The study utilized public domain geophysical and geotechnical data to evaluate the seafloor and near-seafloor geological and geotechnical conditions relevant to floating offshore wind. Data available from published scientific literature and offshore projects were integrated and evaluated using GIS and seismic interpretation software to identify and map geohazards, seabed and subsurface conditions, and key stratigraphic geotechnical units. These results are presented as maps illustrating seabed and subsurface conditions, including geohazards.

Our evaluation of the study area indicates generally favorable conditions for offshore wind development, with site-specific considerations to be factored into engineering design. Key findings related to geological conditions include exposed bedrock, glacial deposits (including exposed glacial till and boulders), and very soft fine-grained sediments. Based on these conditions, the suitability of various foundation concepts is discussed. Other conditions include ocean usage, from fishing activities to vessel traffic. This paper will highlight potential geohazards and provide developers with an understanding of geological and geotechnical conditions in the call area. Understanding of geologic and geotechnical conditions will aid in feasibility assessment for floating wind developments within the Gulf of Maine call area.
Time and Cost-Efficient Characterization of Inlet Hydrodynamics for the Development of Tidal Energy Projects
Authors: Challa R. , Ravens T. M. , Duquette D.
Published: April 2024

In furtherance of advancing a tidal energy initiative, Littoral Power Systems, Inc. (LPS) endeavors to conceive, construct, and assess a comprehensive marine and riverine hydrokinetic current energy conversion apparatus within the Kootznahoo Inlet (Angoon, Alask a) under the aegis of the Advanced Research Projects Agency-Energy (ARPA-E) – Submarine Hydrokinetic and Riverine Kilo-megawatt Systems (SHARKS) project. Systematic surveys of tidal flow velocities, bathymetry, and water levels within the inlet were conducted to discern spatial and temporal flow variations, pinpointing the optimal deployment location for the device. Quasi-synoptic measurements of current speed and direction were captured along cross-inlet transects at the projected location of maximum flow velocity employing an Acoustic Doppler Velocimeter (ADCP). In tandem with these measurements, sophisticated one-dimensional (1D) DYNLET and Delft3D hydrodynamic circulation models were developed for the inlet. The numerical models were pivotal in extrapolating from flow measurements, thereby providing a thorough characterization and validation of spatial and temporal variations. Calibration and validation of the models were achieved using measured transect velocity data, subsequently employed to predict velocity estimates across the inlet throughout the tidal cycle. Comparative analyses revealed the consistent identification of the most robust flows during peak flood and ebb tide, proximate to the southeast side of the inlet (adjacent to the Village Rock) in relatively shallow water depths. The determination of tidal energy resources often entails a time-intensive and costly endeavor. Conventionally, two-dimensional (2D) or three-dimensional (3D) circulation models are developed to furnish time series velocity data, facilitating an assessment of the tidal energy resource at a given site. This paper presents a case study of tidal energy resource assessment and development at Kootznahoo Inlet, incorporating an economical 1D circulation model (DYNLET) in conjunction with a 2D version (Delft3D). The paper delineates the advantages and limitations of the 1D model, juxtaposed with the benefits and limitations inherent in the 2D approach.
Advance Technologies for Efficient Utilization of Well Slots in Offshore Platforms
Authors: Hou Xinxin , Zhang Lei , Xie Tao , Lin Hai , Liu Hailong , Liu Yuyan , Chen Kejin
Published: April 2024

Well slots are the most essential resource in offshore oilfield development, and how to efficiently utilize limited well slots in offshore platform instead of building new offshore platform is the key to improve the economic benefits of oil fields.

Firstly, well slot expansion technology of old offshore platform including hanging well slots inside and outside the offshore platform considering structure strength of old platform. Secondly, sidetracking new wells from old wells with low production is proposed to develop remaining oil near the old platform and sidetracking point is optimized towards deep to reduce footage. Thirdly, combined with reservoir, multilateral branch wells are drilled to improve oil drainage area and enhance oil recovery, moreover, branch bore open hole anchor and external packer are developed to hang sand control screen pipe and maintain wellbore stability instead of leaving branch hole without any sand control methods.

Well slot expansion technology has been used in old platforms, and 35% wells slots have been added to drill new wells to develop remaining oil around old platform. In old well sidetracking, advanced sidetracking tool with high build up rate reaching 120 deg/100 ft is developed and applied in many wells including T shaped well, the sidetracking points have been moved down and the overall footage have been reduced compared with conventional build up tools, and single well construction period have been reduced by 2 days. Multilateral branch wells with 1268 meters long main bore and 2 branch bores have been successfully completed with open hole anchor and external packer to hanger sand control screen pipe, and the production rate is twice as that of the original branch bore without any sand control method.

This technology has been applied in Bohai Oilfield and new platforms have been saved every year as re-utilization of well slots, which can also provide reference for other offshore oil fields.
New Opportunities in Well and Reservoir Surveillance Using Multiple Downhole Pressure Gauges in Deepwater Injector Wells
Authors: Pankaj Piyush , Romero Edgar E. , Jackson Matthew S.
Published: April 2024

In the recent years there has been considerable focus on value creation from downhole instrumentation within oil and gas production wells, specifically in deep water assets where cost of production logging is significant. As a result, injector wells are often overlooked from an instrumentation perspective during development of deepwater fields. As critical as reservoir sweep and pressure maintenance can be to achieving the expected ultimate recovery (EUR), monitoring the injection profile, formation damage, and fracturing through the full well life cycle is often overlooked. This paper shares a study exploring the potential surveillance benefits of deploying downhole pressure gauge arrays in injection wells.

Well, reservoir and injection data were collected for a representative offshore horizontal injection well with a stand alone screen, inflow control device (ICD) completion. Low count, pressure gauge arrays were selected as a potential alternative to fiber optics for injector performance monitoring. A calibrated pseudo steady state well model was created to evaluate gauge array design parameters against ability to measure flow. Downhole pressure gauge array measurements were evaluated against the models predicted injection behavior. Optimum number of gauges to decipher well injection flow distribution, skin build up over time, fracture creating in both longitudinal and transverse directions, and flow blockage in tubing were assessed.

An application of pressure gauge arrays was identified as a potential viable alternative to fiber optic monitoring. The use of pressure gauge arrays in injection well exhibited promising results with accuracy greater than 95% in predicting injection flow distribution. Furthermore, the predictability improves as gauge -to-gauge spacing is optimized. Additionally, localized buildup of formation skin on injectors over time was measurable with high degree of accuracy as the gauge separation was reduced. Hydraulic fractures initiated in injectors showed distinct pressure signature to identify the possible transverse or longitudinal fracture initiation. However, the location of a transverse fracture generated in the near wellbore beyond the screen was more difficult to identify due to the discrete nature of pressure gauge measurements. Well blockage and injectivity index reduction was easily detected by pressure gauges ported to measure inside of the tubing.

Currently, not many case studies exist for deepwater injection well surveillance in the literature. However, as relatively newer surveillance techniques such as fiber optics evolve, this study provides a view into a robust and cost-effective technology that could be a useful tool in solving the questions around well and reservoir surveillance for improved management and proactive response in reservoir maintenance, data handling, interpretation and implementation of insights generated.
The Role of Carbon Capture and Hydrogen in the Energy Transition
Authors: Baliga U. B.
Published: April 2024

Decarbonization is increasingly becoming the new agenda of governments and organizations worldwide. Key factors contribute to the scope and growth of clean hydrogen that include Blue Hydrogen with Carbon Capture with Utilization or Sequestration (CCUS) and Green Hydrogen. The US IRA provides tax credits for CCUS and Clean Hydrogen that will help kickstart decarbonization in the USA. For Blue Hydrogen, CCUS will play a vital role in decarbonization. It is an alternative utilizing available existing infrastructure with a lower investment rather making a full leap to 100% renewable energy for Green Hydrogen. Current Grey Hydrogen production is an intense carbon emitting process. Blue Hydrogen technology using CCUS will play a vital role in this decarbonization pathway as it leverages existing infrastructure with lower investment.

For Green Hydrogen, growth factors include lower cost of renewable power due to improved technology, falling cost of systems integration due to increasing renewable power, improved efficiency of electrolyzer technologies, lower power consumption for green hydrogen, and the need to reduce greenhouse gas (GHG) emissions. Increased investment in renewable energy has increased the impetus for Green Hydrogen that in turn has increased demand-side flexibility. Electrolyzers are scaling up quickly, from megawatt (MW) to gigawatt (GW) scale as technology continues to evolve. Hydrogen producers will need to be diligent in acquiring electricity from low-GHG generators, otherwise electrolysis can exceed the emission levels of traditional hydrogen processes (Grey Hydrogen).

Production of low-carbon hydrogen from fossil fuel sources and clean hydrogen from renewable resources is gaining substantial momentum with a large number of projects worldwide burgeoning during this decade, aptly described as the "Roaring Twenties for Hydrogen." Further acceleration of efforts is critical to ensure a significant share of clean hydrogen in the energy system in the coming decades. While the cost of hydrogen supply from renewables has come down and continues to fall, the urgency of GHG emission mitigation has increased. Many countries have begun to take action to decarbonize their economies, notably energy supply and demand. Ensuring a low-carbon, clean hydrogen supply is essential.
Design Execution and Evaluation of Advanced Completions in Deepwater West Africa
Authors: Pankaj Piyush , Jackson Matthew S. , _ Lokesh , Lopez Thomas , Li Rong Hua , Alves Alvaro , Mohan Kshitij
Published: April 2024

Deepwater wells in offshore West Africa traverse through a complicated faulted block with sand bodies ranging in 10s of meters of thickness. A horizontal or deviated configuration allows wells to intersect and produce from multiple sand formations at once. This also brings in complexity of segmentation along the wellbore with chances of either tapping into gas cap or potential gas build up in zones around the wellbore in time which could render the well uneconomical. The study provides insight into designing advanced well completions in offshore West Africa wells with Autonomous Inflow Control Devices (AICDs) under various challenging reservoir conditions that enable maximizing the producing life of the wells.

Subsurface characterization and engineering models were used to predict well performance under various conditions creating the expectation envelope of possible scenarios in pre-drilled planning phase using a digital-twin model of the well. When the wells were drilled, real time data of wellbore geometry, sand interval lengths, permeability and fluid phase saturations were estimated which were used to revalidate, revise, and optimize the design of lower completions including placement of packers and AICDs. Further, compaction well operability limits were defined using the geomechanical analysis to provide guidance on the well start-up without formation collapse. Once the wells were turned on for production, the digital twin models were recalibrated, and drawdown was readjusted for optimizing production performance.

The study presents two wells’ case studies with completely different production strategies – one with existing gas cap and other with potential gas cap build in time. The engineering approach allowed designing lower completion in both the wells and without which the wells would otherwise be dominant gas producers in their producing life (early or later) and become inoperable with gas handling constraints at surface. Efficient design maximized oil productivity and allowed reservoir fluid influx control for efficient reservoir maintenance. Production of gas was suppressed by over 600% and an equivalent increase in oil production was achieved with the optimized completion design.

Integrated subsurface understanding, reservoir characterization, completion engineering and execution of advanced completions in the wells maximized the oil productivity and delay the gas influx into the well. The engineering workflow designed in the study has become the framework of decision making in designing lower completions for future wells with complex zonal segmentation of reservoir or potential gas/ water influx in time.
Recommended Design Practices for Enhanced Well Productivity in Multi-Zone Completions with Large Variations in Zonal Pressures
Authors: Serra M. , Nadeem A. , Burke K. , Rodgers J. P.
Published: April 2024

Perforating multiple zones in a single deep-water well, where the zonal pressures between reservoirs differ significantly, at times in excess of 2000 psi, presents substantial challenges in developing and maintaining sufficient dynamic underbalance for effective perforation cleanout across the zones. The principal objective of this study is the development of recommended design practices for perforating deep-water, extended reach, step-out wells that present such challenges.

Design practices were evaluated through the perforation strategy optimization of four multi-zone, deep-water wells situated in the Jubilee Field, off the coast of Ghana. The sensitivity of dynamic underbalance generation and perforation cleanout performance to changes in readily modifiable gun system characteristics was studied. This includes charge loading, string positioning and management of gun free volume. Multi-physics simulation was used to resolve the fluid and structural dynamic responses of the system during perforation. The applied methodology provides enhanced visualization and resolution of the system-wide dynamics during this highly energetic event. It accounts for the complexity of the material interactions and the resulting 3-dimensional loading on the string from charge detonation, casing fragmentation and high-speed fluid flows [Glenn, 2014]. To build confidence in this analytical approach, pressure data recorded downhole was used to close the loop on the process and calibrate the simulations against their respective job histories.
Greenfield Production Development: A Comprehensive Process Review to Reduce Schedule Since Discovery to First Oil
Authors: Smolka R. B. , Canova M. D. , Mascarenhas L. S. , Murakami C. Y. , Lins F. Holanda , Andrade L. D. , Sousa A. G. , Serra R. S. , Ribeiro M. S. , Machado T. B. , de Sá A. Nicolino
Published: April 2024

This article describes a framework to a Petrobras approach to greenfield development based on a set of strategies, process review and solutions to reduce the time between a new discovery and its first oil, presenting gains and challenges to implementation. The methodology presented in this study encompasses: Definition of a target to a greenfield development; A comprehensive processes review with information flows mapping, critical paths of activities, interdependencies, and main schedule offenders identified from pre-discovery to first oil production; Structuring a set of solutions, initiatives, and levers for time gains in an integrated manner among all stakeholders, including paradigm shifts and change management applied to the company portfolio; and a program management office. The achieved results were a set of approximately 70 initiatives with assumptions, new processes, and strategies considering technical and business disciplines to be applied in production development projects from discovery to first oil. This comprehensive process review concludes that there are alternatives for reductions in greenfield project schedules that could potentially reduce about 30% of the time to first oil when the assumptions of the solutions are met, and the optimistic scenario is revealed in the discovery and appraisal. However, we highlight the necessity of risk and return evaluation for each solution, as well as the need for changing the company's standards, norms, and organizational culture.