bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Study of the Condensate Banking Effect in an Unconventional Gas Condensate Reservoir with Hydraulically Fractured Wells
Authors: Yin Jichao , Li Han Jake , Ruidiaz-Santiago Cyd Marie , Nguyen Huy , Senior Peter , Raba Osama , Esmaili Soodabeh , Xie Xueying , Liu Shunhua
Published: September 2024

As unconventional assets mature, gas condensate reservoirs are increasingly being targeted for development. However, gas condensate reservoirs are prone to wellbore productivity losses due to a two-phase flow caused by condensate banking when pressures drop below the dewpoint. Conventional reservoir mitigation strategies minimize condensate banking by maintaining flowing bottomhole pressures close to dewpoint pressures. However, using this approach with unconventional reservoirs raises concerns, as primary depletions and hydraulic fractures in long horizontal wells make maintaining dewpoint pressures implausible. Therefore, to provide a more effective mitigation solution for optimal field development, the severities of unconventional well condensate banking must be reevaluated.

This paper investigates condensate banking effects on well performance by conducting field modeling studies on Delaware Basin deep Wolfcamp condensate producers using compositional simulation models with hydraulic fractures. Three-dimensional (3D) geologic models were constructed based on facies distributions. Fracture models were based on high-fidelity geomechanical models. A 11-component Equation of State (EOS) model was calibrated using a pressure/volume/temperature (PVT) sample. Full field reservoir simulation models were built to match well pressure and production rates.

The models found condensate banking to be of minimal concern, as condensate dropped out mostly in fracture networks and could be efficiently produced through highly conductive fractures. An optimal development plan with an aggressive flowback strategy, validated by actual Permian Basin gas condensate well performance, is therefore proposed, which should improve the project value without a condensate banking risk.
Comparative Analysis of Microbiological Testing Technologies Used in the Energy Industry
Authors: Taylor N. M. , Walker A. , Nicoletti D. , Po K. , Goldsmith C. , Gieg L. M. , Demeter M.
Published: September 2024

Within the energy industry, there are several technologies used to quantify microbiological contamination of fluids and assets. Some of these technologies can also be used to identify or characterize microorganisms of interest. It is important to understand the scope of detection and limitations of individual assays so that accurate, data-driven decisions can be made.

Three fluids varying in chemical composition and origin within the energy sector were tested in this study. Serial dilution for detection of acid producing bacteria (APB) and sulfate reducing bacteria (SRB), activity-reaction tests measuring SRB, an assay quantifying bacterial hydrolases, and adenosine triphosphate (ATP) quantification were compared and assessed against molecular microbiological methods (MMM). Data were collected to determine the ease of use, precision, and comparability of the testing technologies to each other. A kill study using organic biocides evaluated the performance of these tests in quantifying changes in the microbiological populations over time.

The testing technologies delivered results on the order of minutes (ATP and enzymatic assays) to days (activity-reaction tests and MMM) to weeks (serial dilution). Comparing data from 1stgeneration ATP and the bacterial hydrolase tests to the data generated by the other technologies proved challenging due to the lack of reference standards and equivocal nature of the raw output from those technologies. A relatively high limit of detection was determined for 1st generation ATP technology in fluids where the bioburden was estimated below 104 cells/mL. Interpretation of results in culture-dependent activity-reaction tests was found to be subjective, requiring users to distinguish between visual indicators to estimate bioburden. This was further confounded when testing fluids for industrial uses that have complex mineral content and turbidity. The choice of culture-dependent technology to enumerate SRB resulted in up to 3-log SRB/mL variance compared to other tests. Variable responses of assayed biomolecules to chemical treatment (e.g., biocide) were notable in the kill study, where the choice of testing technology impacted the interpretation of biocide effectiveness.

Accurate evaluation of microbiological contamination is essential to operational decision-making in the energy industry. Understanding the strengths and limitations of different testing technologies ensures optimized chemical treatments, reduced costs, and improved environmental outcomes.
Deepwater Open Water Work Drilling Optimization
Authors: Lafferty C. , Thomas J. , Rashid A. , Fazal A. , Kudlaev I. , Rawlins S.
Published: September 2024

The use of motorized rotary steerable system (RSS) and advanced measurement-while-drilling (MWD) tools optimized the open-water work (OWW) scope of deepwater drilling operations in Guyana. The objective was to improve drilling efficiency, reduce slide mode drilling, and enhance directional control. While similar BHAs had been used in vertical wells in the Gulf of Mexico, their application in the challenging OWW scope in Guyana was a novel endeavor.

To overcome the limitations of the standard bottomhole assembly (BHA), a novel approach was adopted, incorporating a 26-in. rotary steerable system, straight mud motor, and advanced MWD for dynamic surveying. Detailed planning and tool selection, including RSS and motor tendencies analysis, were crucial for establishing initial motorized RSS BHA design. Ten out of fourteen planned wells used motorized RSS BHA, while the remaining four employed a motor and gyro due to anticollision concerns. The study involved optimizing BHA configuration, drilling parameters, and survey acquisition processes to enhance performance.

The implementation of the motorized RSS along with advanced MWD tools led to significant improvements in deepwater drilling operations in Guyana. A 75% improvement in drilling efficiency was achieved compared to previous conventional drilling assemblies. The use of the motorized RSS BHA design resulted in the elimination of slide mode drilling, enabling directional objectives to be met more effectively. The average 26-in. section drilling time was reduced by 18 to 28 hours per well. This method allowed for better control and reduced borehole tortuosity, ultimately improving well performance. The success of this approach has now become the standard for future OWW campaigns in the region.

Apart from the enhancement in drilling efficiency, this case study has not only pinpointed solutions to overcome directional challenges but has also paved the way for the industry to attain higher inclinations in top hole. This achievement, in turn, addresses challenges encountered in intermediate and production sections by facilitating the creation of smoother catenary curves and delivering less tortuous boreholes. The implications extend to the realm of production and completion, providing a foundation for more streamlined processes and improved precision in the installation of production and completion components.
Experimental Investigation on CO2-Sensitive Gel-Type Sealant for Sealing Leaky Carbon Sequestration Wellbores
Authors: Anwar Ishtiaque , Meng Meng , Carey J. William , Gilbertson Robert , Zandanel Amber , Himmelberg Nevan , Zhang Weicheng , Tao Emily , Neil Chelsea , Nair Rajesh
Published: September 2024

Potential upward leakage of CO2 and reservoir fluid within a leaky sequestration well poses potential environmental and economic risks. This study explores the latest methods for fixing wells in challenging situations where CO2 is present. An in-depth series of tests was carried out to examine how a special methyl methacrylate-based gel, modified to react to CO2, behaves and functions in carbon capture areas. The experiment looked at how much the gel expanded over time using laser profilometry to measure its growth under various conditions. The study also measured the gel's properties and its ability to seal when there was no CO2 present by comparing the behavior of different concentrations of sealant. Tests using thermogravimetric analysis and thermo-stability measurements were carried out to understand the sealant's reactions at higher temperatures, as well as carbon dioxide leak tests under downhole conditions, were also part of the research. The study found that the gel's effectiveness in sealing wells is influenced by several factors including exposure time, concentration of gel (monomer), substance used to trigger the reaction (CO2, for instance), and temperature. The research demonstrated that the gel-based sealant was able to expand up to 20 times its original size when exposed to CO2 and moisture. Additionally, the sealant showed a high capacity to resist, maintain its structure, and work at high temperatures (up to 140°C) and CO2 pressure (approximately 1550 psi). Moreover, experiments suggested that the sealant naturally formed a seal with CO2 over time, reducing the chance of leaks and completely stopping them at the right concentration.
Paraffin Production in Eagle Ford: Learning, Applying, and Executing Out of Box Strategies for Living with This Challenging Issue
Authors: Contreras Jesus D. , Vasquez Javier R. , Harton Trey W. , Garikipati Prapul
Published: September 2024

Since the beginning of Eagle Ford development, paraffin production has created significant production losses in wells downhole, well pads and gathering systems. The organization has performed multiple strategies trying to mitigate the problem including chemical injection, hot water/hot oil treatment (downhole) and pigging activities (gathering system).

Nevertheless, a formal solution, if something like that exists, has been elusive. Historically, the approach to paraffin issues in the field has been reactive. In 2020, the team began investigating a more proactive approach with the creation of an integrated hydraulic model to improve pigging operations within the gathering system.

Also, operational data combined with data analytics techniques was used to identify a specific pattern that revealed more about the deposition process at low pressure and low temperature conditions under which paraffin is regularly observed.

This paper will explain that through the discovery of specific pressure trends, at pad level (surface), combined with an unconventional approach for analyzing gas compositional data, it was possible to both detect and predict paraffin deposition at pad level (surface), and in the gathering system, including conditions where paraffin was in suspension (that cannot be observed using conventional tools/methodologies). These workflows completely revolutionized the pigging strategy and ultimately reduced production losses by more than 90%.
Three-Level System to Determine and Correct Real Time Drillstring Vibration
Authors: Carrillo L. A. , Flores R. , Suarez H. , Morales J. P.
Published: September 2024

This paper aims to identify the impact of parameters: Rate of Penetration (ROP), Torque, and Weight on Bit (WOB) on the Specific Mechanical Energy (MSE). This concept has been implemented to evaluate bit performance, determine drilling efficiency, and analyze if the bit adequately utilizes the energy and is not dissipated elsewhere (vibration). However, MSE alone does not differentiate between the causes of inefficiency and additional energy used in drilling. Various studies have analyzed this parameter along with the MSE/DS (MSE/Drilling Strength) ratio to determine if drilling inefficiency is due to rock hardness, vibrations, bit wear, or bit balling (Raul Flores, CMP 2024). Continuing with the study, we have the following:

A three-way protocol to determine and correct drill string vibration is presented with a simplified methodology. When using the original MSE equation, there are two terms: torsional load and axial load. Studies concluded that the axial load can be omitted, yielding the same result. Also, in terms of trend analysis, MSE behaves the same over the drilling time. The MSE/DS ratio led us to a simplified equation called the Ratio Factor (RF), a quick-to-calculate optimized factor. The RF is the ratio between the rotational forces and the normal axial forces on the bit. 3 case studies are shown, where based on the behavior of the MSE and the RF, the problems presented were identified and corrected, Well 1: vibrations, well 2: Bit wear and well-3: Impact of the MSE values.
Insights into the Impacts of Heterogeneity and Capillary Pressure in CO2 Storage in Depleted Gas Reservoirs with a Focus on Water Backflow and Hydrate Formation
Authors: Fernandes B. R. B. , Delshad M. , Indina V. , Farajzadeh R. , Machado M. V. B. , Sepehrnoori K.
Published: September 2024

With the growing demand for geological storage of CO2, depleted gas reservoirs are becoming attractive targets due to proven caprock and existing infrastructures. However, Joule-Thomson cooling can pose a flow assurance risk leading to the formation of hydrates and possible injectivity loss. This study investigates the impacts of capillary pressure and permeability heterogeneity on the formation of hydrates during CO2 storage in depleted gas reservoirs. A compositional thermal reservoir simulator is used to model the fluid and heat flow of CO2 in methane and water-saturated reservoirs. The dissociation and formation of methane and CO2 hydrates are modeled using kinetic reactions to calculate porosity and permeability reduction during hydrate formation. The capillary pressure is scaled using the Leverett J-function to account for variations in porosity and permeability values. The water residual saturation is also correlated with permeability. Variograms are used to generate areal heterogeneity for multilayered reservoir models. Sensitivities to injection rate and wellhead temperature are also performed. The results indicated that the Joule-Thomson cooling is increased with lateral heterogeneity, leading to more formation of hydrates. The heterogeneity created low permeability zones near the injection well, leading to higher pressure drawdown which intensifies the cooling effect. The reduced water saturation during the injection of CO2 altered the capillary pressure and resulted in water backflow and crossflow. The magnitude of capillary-driven backflow and crossflow was observed to be a function of the capillary pressure gradient. For cases with hydrate formation, a complete conversion of water in the pores to hydrate and ice resulted in porosity reduction proportional to its water content and injectivity reduction as high as 30% for multilayered cases. However, water backflow provided a continuous source of water for hydrate and ice formation in low permeability layers which lead to near well plugging. The water backflow due to the capillary pressure gradient can intensify the risk of hydrate formation by more water content in the near wellbore.
Repurposing Depleted Wells for Geomechanical Pumped Storage
Authors: Balushi Faras Al , Taleghani Arash Dahi
Published: September 2024

Geomechanical Pumped Storage (GPS) is an innovative renewable energy storage method that utilizes the elastic deformation of subsurface formations to store and retrieve water for electricity generation during peak energy demand periods. By leveraging the elastic properties of underground formations and the lifting of overburden, GPS stores water within hydraulic fractures. This study aims to identify the most efficient GPS design to maximize energy storage in subsurface formations focusing on the hydraulic connection between the wellbore and the fractures. We developed a Mechanical Earth Model (MEM) to simulate different fracture closure modes including uniform and mouth closure modes. We modeled the interactions between fluid flow and rock deformation during water injection, storage, and recovery phases using poroelasticity principles. Results indicate that uniform fracture closure mode reduces fluid loss, thereby improving energy storage and recovery efficiency. Converting abandoned oil and gas wells into GPS sites could also reduce costs, which offers an adaptable and cost-effective energy storage solution.
Fracture Conductivity with Application of 3D Printing Technology
Authors: White V. A. , Arias J. Colina , Zhu Ding , Hill A. D.
Published: September 2024

Fracture conductivity is a measure of the success of completion designs and subsurface fracturing treatments from fractured well performance. Conductivity can be evaluated from experimental investigation. Traditionally, samples for conductivity experiments involve fracturing downhole or outcrop rocks to create realistic fracture surfaces capturing diverse morphologies. Previous studies show that fracture topography strongly influences the conductivity created, and therefore fractured well performance. However, the distinctive nature of these surfaces hinders repeatability and complicates the identification of rock characteristics impact on conductivity. In this research we use 3D printing technology to generate repeatable conductivity test samples with statistically controlled parameters to characterize fracture surface roughness and rock geomechanical properties. The test procedure provides a more isolated evaluation of the factors that control the resultant conductivity.

A digital fracture surface model was generated using Geostatistical Software Library with application of mean deviation, standard deviation, and correlation lengths as changing parameters that influence surface roughness. Two mirror sides of fracture sample were made digitally as replica of original fracture samples. Molds of samples were printed with a Liquid Crystal Display (LCD) Ultra-Violet 3D printer using a selected 3D printing resin. Then the testing samples are made with cement that has appropriate mechanical properties from the molds. Several physical samples of fracture conductivity test were created with cement and the printed molds. All samples have the standard API conductivity dimension, and the conductivity tests follow the modified API conductivity test procedures. The proppant used in the tests include local 100-mesh sand and 200-mesh sand.

The experimental results show a good repeatability of the 3D printed samples, which confirms the consistency of the experimental procedure. From that point, the comparisons of different proppant type, size and concentration on conductivity are made, and conclusions on proppant selection for optimal conductivity are generated.

The procedure developed in this research eliminates the uncertainty of randomness of individual fractured rocks, and better evaluates the effect of the type and size of proppant on fracture conductivity for different fracture surface topographies. The finding of this research help to understand fracture conductivity as a function of geostatistical features of the fracture surface, and the effect of proppant type, size and loading on fracture conductivity and fractured well performance. This can be used in fracture designs for more efficient treatments.
Project X Complex Transportation & Installation Campaign; Strategies & Scheduling for Greater Cost Effectiveness
Authors: Kassim K. , Ngadiman H. B. , Rahman K. A. , Shahudin F. , Marimuthu M.
Published: September 2024

This paper discusses on the methods of the installation of platforms, pipelines and subsea fiber optic cable including its challenges the subsequent mitigations. The knowledge is based on the successful installations of Project X Gas Development Project consist of a CPP, flare tower & riser platform, 28" × 81km pipeline from CPP to riser platform and 8km CPP to nearby platform of subsea fiber optic cable.

The methodology applied in the installation of the CPP jacket is via reverse launch and self upending method. The CPP topside is installed via longitudinal floatover method. The rest of the jackets, topside and other structures was lifted and installed by main work barge. The pipeline was installed via typical S-lay pipeline installation utilizing automatic welding system for the pipelaying and stalk-on of risers at both sides of the platform. The inspection is using Automatic Ultrasonic Testing (AUT) complete with the Engineering Criticality Assessment (ECA) and precomm activities were performed as well. The subsea fiber optic cable has been laid and post trenching was performed to bury the cable.

There are multiple approaches that a company can take to reduce the schedule and ultimately reduce the cost of offshore installation. For platform installation for example for this project is on the self upending method for jacket installation whereby less main work barge cranage capacity can be used to upend the structure underwater. The flare tower and riser platform jacket were installed using a double block upending method as the HLV crane is equipped with split block configuration on the main hoist. This reduces the duration as it eliminates the flooding and buoyancy requirement including reduction in lifting points. Furthermore, floatover installation with integrated topside design significantly reduces the duration of offshore installation including the need to have high cranage capacity to lift the topside. For pipeline installation, stalk-on of risers reduces the need to flood to pipeline prior to riser installation and eliminates a weak point of subsea flange connection for this gas pipeline. Furthermore, an overall study of the pipeline in flooded and operational condition can reduce the numbers of concrete mattress installation required to meet the design requirement. For subsea fiber optic cable, a post trenching machine that is less sensitive to weather ie. that can perform the work during monsoon, can further improve the schedule of the offshore installation. The overall schedule was improved by 20% and subsequently the cost implicated is reduced as well.

The diverless platforms installation including reverse launch self upending method for jacket installation and longitudinal floatover topside installation are the few novel approaches in the project.
Thermo-Catalytic Decomposition of Methane to Produce Low-Carbon Hydrogen and Solid Carbon
Authors: Ishak M. A. , Chai I. C. H. , Chan Y. H. , Nikulainen K. E. , Laukka J. , Hazri H. S.
Published: September 2024

The study explores the use of thermo-catalytic decomposition (TCD) of methane to produce hydrogen (H2) and solid carbon. The research focuses on the performance of a proprietary molten metal catalyst in a TCD reactor, evaluating methane conversion efficiency and carbon quality under various operating conditions, including flow rates, pressure, and temperature. The results demonstrate that increasing the temperature from 920°C to 1030°C enhances methane conversion efficiency from 61% to 94%. Catalyst loss was minimal at 0.03%/day, primarily due to manual solid carbon removal. The study also found that higher pressure (from 1 to 12bar) increases H2 yield, from 69% to 85%. The solid carbon produced includes valuable forms such as cryptocrystalline graphite (CG). The TCD process shows an 80% reduction in CO2 intensity compared to traditional steam methane reforming (SMR). This novel approach, termed Turquoise hydrogen production, is economical, modular, and does not require clean water or precious metals, offering potential economic benefits through the sale of high-value carbon materials.
Advancements in Production Optimization through an Innovative Hybrid Data-Physics Architecture
Authors: Matoorian Raya , Malaieri Mohammadreza , Shor Roman , Aguilera Roberto
Published: September 2024

This research addresses the challenges in using machine learning (ML) to assess and optimize production in unconventional wells, where computational costs (dependence on the accuracy of physical models) and complexity of wellbore design create significant challenges for decision-making and field development. A novel Hybrid Data-Physics (HDP) architecture is proposed that integrates data-driven models with physics equations embedded in a deep neural network (DNN). This approach optimizes both network and physical parameters simultaneously to predict short and long-term production rates, thereby generating more realistic operational scenarios.

Using a comprehensive dataset from nearly 1300 Duvernay wells within the Western Canadian Sedimentary Basin (WCSB), the proposed HDP model significantly improves production performance estimations by refining physical parameters through iterative neural network processes. The model performs exceptionally well even with limited data, particularly in unconventional wells where geological complexities pose challenges for traditional simulation methods. By incorporating simpler equations such as decline curves, the HDP model bypasses the need for complex physics, capturing hidden complexities and operational trends.

This study highlights the HDP model's transformative potential in production optimization, merging data analytics with physics-based modeling to enhance operational insights and decision-making. This pioneering approach reduces uncertainty and adapts to dynamic conditions, offering a robust, efficient tool for unconventional reservoir management. Additionally, the HDP model's ability to integrate various data types and adapt to evolving conditions underscores its versatility and practical applicability in real-world scenarios. Through this integration, the model not only enhances predictive accuracy but also provides a scalable solution that can be tailored to diverse reservoir conditions and operational needs.
Development and Evaluation of an Alternative Fluid for Offshore Fracturing of Moderate to High Permeability Formations
Authors: Vitthal S. , Van Zanten R. , Malbrough J. , Tallin A. , Reynolds M. A. , Dawson J. , Hoeman K.
Published: September 2024

For decades, borate crosslinked guars have been the workhorse for fracturing conventional and higher permeability formations particularly in offshore operations. The development of shales/unconventional reservoirs has led to many new learnings and innovations including new fracturing fluids. In shales, uncrosslinked polyacrylamides (PAs) at low gel concentrations (0.5-2.0 gpt) have become the dominant fluid because of their lower cost, greater friction reduction, and higher retained conductivity. The use of these fluids is commonly regarded to be limited to unconventional formations where permeabilities are in the nano-micro darcy range.

Recently, some conventional low permeability (0.1-1 mD) reservoirs have been fractured using higher concentrations (4-12 gpt) of PA in place of crosslinked gels with encouraging results. The potential of these fluids for fracturing of even higher permeability formations (10-1000 md), as commonly found offshore, has not been investigated.

This paper describes the identification and evaluation of a linear polyacrylamide (PA) fluid designed to meet the technical specifications for fracturing deepwater/offshore wells in higher permeability formations. Early evaluation identified that a very high polymer loading of 40 gallons per thousand(gpt) would be needed to meet the challenging requirements for offshore application. The evaluation of a 40 gpt polyacrylamides for use as a fracturing fluid has not been looked at by the industry. The qualification and testing program evaluated fluid compatibility, rheology, proppant conductivity, regain permeability, fluid loss, and fluid friction in comparison to a typical 35 pounds per 1000 gallons (lbm/Mgal) borate crosslinked (XL) gel. The practicality of pumping the PA system was also evaluated by an SIT test from an offshore stimulation vessel.

The results show that the 40 gpt PA fluid appears to be an attractive alternative to borate crosslinked fluids for offshore fracturing. Its benefits include higher fracture conductivity for improved productivity, reduced formation damage, lower friction pressures, and simpler QC with fewer additives. In some cases, these fluids could replace high density XL-based fracturing fluids needed for fracturing over pressured reservoirs. The SIT test confirmed its feasibility for use in offshore fracture operations.
Saudi Arabia Southern Area Oil Operations Achieving 1 Million Metric tonCO2e Emissions Avoidance
Authors: Elayoubi E. M. , Gercek S.
Published: September 2024

Reducing carbon emissions is a strategic action for the oil and gas industry to improve its sustainability and resilience in the face of evolving global energy demand and environmental regulations and the need to mitigate the impact of climate change. Despite the seemingly existing paradox of producing energy while reducing emissions that result from it; this paper aims to show that it is feasible and can be accomplished. Further, this paper presents a case study of Saudi Aramco, Southern Area Oil Operations (SAOO) that successfully reduced more than 1 million metric tons of carbon dioxide equivalent (tCO2e) emissions through various initiatives over the course of 3 years. SAOO set in motion a plan that has a combination of measures including energy efficiency projects, replacing equipment with lower carbon footprint, reducing flared gas volumes, and implementing a rigorous fugitive emissions detection and repair program. Moreover, this paper highlights the environmental benefits of the multitude of implemented initiatives, which ultimately led to avoiding emissions of more than 1 million metric tCO2e over a 3-year period. Along the way, SAOO availed non-renewable natural resources of oil, gas and water, as well as electricity. Additionally, SAOO improved efficiency of its operations and energy consumption; all leading to saving money while meeting customer demands safely and in an environmentally sound manner. Furthermore, insights into the challenges faced and lessons learned during the implementation process will be shared. Finally, this paper shows that reducing carbon emissions can serve the oil and gas industry meet energy demands, while addressing increasingly more stringent environmental regulations, all while staying profitable, and improving sustainability.
Development and Qualification of a High Angle Multi-Frac (HAMF) Completion System for Deepwater Subsea Wells
Authors: Vitthal Sanjay , Goncu Aykut , Spencer Virginia , Jackson Ian , Xiao Xiaohui , Song Christy Y. , Vanee Mike , Cheeseman Brenton
Published: September 2024

Deepwater developments in the Gulf of Mexico have historically focused on high kH (∼10,000 – 100,000 md-ft) Miocene reservoirs. Production from a single sand in these prolific reservoirs has been sufficient to justify the high costs of a deepwater well. In the last decade, there have been significant volumes discovered in Upper/Lower Wilcox age reservoirs in the Gulf of Mexico. These new discoveries typically comprise of stacked sets of lower permeability (1 – 20 md) sandstones. Several of these Wilcox discoveries have been successfully developed using cased hole vertical wells and single trip multi-zone frac-pack completion systems. Despite some of the successes, the project economics of vertical fractured wells in the lower Wilcox remains challenging due to low recovery factors (8 – 20%) and low EUR/layer.

This paper describes an alternative lower completion concept for developing these lower Wilcox reservoirs referred to as a High Angle Multi Fractured (HAMF) well design concept. The value of the HAMF concept was assessed via reservoir modeling to understand it's value for low mobility reservoirs. Supporting evidence on the EUR uplift from analogue field studies and analytical modeling is also shown.

Functional specifications for the completion system and the frac sleeve were developed based on the reservoir and operational requirements for subsea installations. Following design reviews, a completion system was selected that met the requirements, albeit with some modifications. The selected sleeve system was designed, manufactured, and went through comprehensive qualification and testing. A horizontal cemented 10 sleeve system was installed and hydraulically fractured in a land trial to evaluate the system functionality. Diagnostic evaluation including downhole gauges, radio-active tracers and 3D acoustic imaging are presented.
Bonding Strength at the Cement-Casing Interface in Hydrogen Storage Wells
Authors: Zhan Zhuochen , Wang Junpeng , Taleghani Arash Dahi , Elsworth Derek
Published: September 2024

Given the growing interest in both short- and long-term underground hydrogen injection and reproduction, ensuring an impermeable sealing of the storage space for successful hydrogen containment is critical. Therefore, it is crucial to assess the capacity of borehole cement to maintain geomechanical integrity in the presence of changes in interfacial characteristics resulting from hydrogen exposure at the cement-casing interface. This study investigates how exposure to hydrogen affects the bonding strength and mechanical characteristics at the cement-casing interface in hydrogen storage wells typically remediated through squeeze cement jobs. New correlations link bond strength measured in double-direct shear (DDS) with x-ray micro-computed tomography (µ-CT) and ultrasonic velocity measurements. Compared to cement samples treated with nitrogen, the DDS tests showed a substantial reduction in shear bond strength for cement samples exposed to hydrogen, with a noticeable decrease in maximum shear strength and higher ductility. µ-CT imaging revealed that cement samples treated with hydrogen had increased bulk porosity with noticeable fractures, indicating weakened structural integrity of the bulk cement. These results were confirmed by ultrasonic velocity measurements, which revealed that samples treated with hydrogen had significantly lower P-wave velocities and Young's moduli. Such reductions in strength, indexed through reduced stiffness, highlight the risk of debonding and matrix cracking under repeated injection and production cycles. Importantly, both the cohesive strength at the cement-casing interface and the strength and stiffness of the cement decrease after exposure to hydrogen.
AI-Driven Environmental Data Extraction for Energy Sector Assessment
Authors: Chen Zhenlin , Zhong Roujia , Long Wennan , Tang Haoyu , Wang Anjing , Liu Zemin , Yang Xuelin , Bo Ren , Littlefield James , Koyejo Sanmi , Masnadi Mohammad S. , Brandt Adam R.
Published: September 2024

The oil and gas industry continually seeks to enhance environmental stewardship and reduce its operation carbon footprint, with carbon intensity reduction being a key objective. However, the lack of comprehensive and accessible global real operation data hinders accurate environmental assessment, climate modeling, and decision making. This challenge is exacerbated by the dispersion of crucial information across various sources and the high costs and legal aspects associated with accessing proprietary databases. This paper introduces an innovative framework leveraging Large Language Models (LLMs) - specifically applying GPT-4 and GPT-4o - to extract critical oil and gas asset information from diverse literature sources. Our approach aims to bridge the gap between proprietary and open-source information, creating a more accessible database for different sectors such as industry stakeholders, policy makers, and investors.

Our evaluation process rigorously assessed the LLM's performance, categorizing extractions into true positives, false positives, and false negatives. We employed key metrics including true positive rate, precision, and F1 score to balance the framework's ability to correctly identify relevant information with its capability to find all pertinent data. An iterative fine-tuning process allowed us to address specific challenges in oil and gas data extraction, such as distinguishing between active and production wells.

We developed a novel LLM framework that conducts iterative comparisons between GPT-4's output and a dataset of 108 ground truth documents which were meticulously labeled by domain experts. Through 11 training and testing iterations, we fine-tuned prompts to optimize information extraction. The framework achieved impressive results, with a true positive rate of 81.44% and an F1 score of 76.78% on the testing dataset.

The framework demonstrated significant efficiency gains, processing 32 documents in 61.41 minutes with GPT-4o, averaging 7.09 seconds per extraction. This represents a substantial improvement over traditional manual method. Moreover, the cost-effectiveness of the approach, with GPT-4o reducing extraction costs by a factor of 10 compared to GPT-4, makes it accessible to a wider range of researchers and organizations.

This research has far-reaching implications for the oil and gas industry. By creating an organized, transparent, and accessible database, we aim to democratize access to critical information, potentially revolutionizing how data is extracted and utilized in this field and beyond. This framework could support more accurate climate modeling efforts, enhance decision-making processes for operations and investments, and contribute significantly to the sector's ability to meet environmental commitments, particularly in areas such as emissions reduction and energy transition strategies.
Efficient Drillstring-Wellbore Contact Model and Implications for Real-Time Modeling of Complex Downhole Mechanics
Authors: Wilson J. K.
Published: September 2024

Determining the contact forces between the drillstring and wellbore wall remains a computational challenge; one that prevents real-time estimation of complex downhole mechanics. In order to achieve automation of engineering analysis for real-time dysfunction detection and response, this is a limitation that must be overcome. While current models are capable of providing accurate results for complex scenarios, they can be quite costly, especially for larger drilling assemblies (i.e. full length drillstrings). For reference, a state-of-the-art nonlinear finite element model might take 2 hours to calculate the deflections/rotations and forces/moments of ~20,000+ ft of drillstring. The goal should be the development of a model that can obtain the same result within a minute, if not seconds.

Using a validated nonlinear finite element model as an initial comparison, a new drillstring contact algorithm has been developed that can provide similar results in a fraction of the time. The new approach utilizes a direct integration scheme of forces, moments, rotations, and deflections along the drillstring. Contact forces are then determined iteratively over the length of the drillstring. This results in a performance improvement over traditional nonlinear approaches, which rely on the calculation of incremental displacements to determine the precise location and magnitude of contact forces. The new contact iteration is distinct from previous iteration approaches in that it can process multiple contact points in a single iteration, while previous algorithms are limited to adjusting only a single contact point per iteration.

The results show a 100-300% improvement in computation time, depending on the individual scenario. For smaller drilling assemblies, such as Bottom-Hole Assemblies (BHAs) with total lengths of a few hundred feet, the computation time reduction is generally on the lower end. The larger time savings occur for full drillstring assemblies that are 10,000-20,000+ ft long. Direct comparisons are shown for increasingly complex scenarios, from deflections of BHAs in 3-dimensional wellbore profiles, to full drillstring assemblies in challenging horseshoe wells. The model is further compared directly to measured downhole bending moment data, with a very good agreement between field-measured and calculated values.

This novel wellbore contact algorithm is presented to show what is possible when applying new methods to "old" problems. The new approach has enabled a drastic reduction in the amount of computation time needed to obtain a result. Promising results have set the stage for future development of modeling software and integration into real-time architectures.
Accelerated Carbon Capture and Storage via Mineral Carbonation: A Laboratory-Scale Investigation
Authors: Karabayanova Leila , Hajiyev Murad , Isabel Hernandez Madero Mariam , Sutherland Blake Edward , Harris James Bradley , Qureshi Ibrahim , Hascakir Berna
Published: September 2024

Carbon Capture and Storage (CCS) is globally recognized as a vital, strategic approach to reduce anthropogenic CO2 emissions and mitigate the adverse effects of climate change. Among various sequestration methods, mineral trapping is recognized for its superior safety and extensive CO2 storage capacity. This study presents a novel methodology for assessing the rapid mineral carbonation of CO2 through geochemical interactions with carbon-, magnesium-, and iron-rich minerals abundant in geological formations.

Four minerals: olivine, dolomite, magnetite, and gypsum, have been selected as candidates for the study and exposed to CO2 at various heating rates and temperatures, utilizing Thermogravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC) to establish the optimal conditions for carbon mineralization at atmospheric pressure. Furthermore, the study examined the effect of the aqueous phase with low and high ionic strength on minerals’ carbon uptake efficiency. A novel combined analysis of the minerals was conducted before and after CO2 exposure using Scanning Electron Microscopy/Energy Dispersive Spectroscopy (SEM/EDS) with the normalization by TGA/DSC data to quantify the total carbon uptake by each mineral, thereby identifying the best candidate for mineral carbonation.

Results showed that olivine and dolomite in a dry state displayed the highest carbon uptake values at 200˚ and 100˚ C temperatures, respectively. Thus, it was proved that accelerated carbon mineralization is possible even in the absence of an aqueous phase. However, introducing a water phase with high ionic strength to the mineral surfaces resulted in a significant increase in carbon uptake, with an average rise of 5-15 mg per 100 mg of mineral in olivine and dolomite correspondingly. Furthermore, it was found that dolomite requires more heat to store large amounts of carbon facilitated by the high heating rate of 20˚C/min, whereas olivine demonstrated higher carbon uptake values at a low heating rate of 5˚C/min. Hence, strong correlations between carbon uptake values and the heating rates for both minerals have been established. Lastly, it was concluded that the surface void spaces of the minerals were highly affected by the addition of the aqueous phase to the mineral.

The pioneering approach and findings of this paper reveal that carbon storage can be successfully implemented in a matter of hours under laboratory conditions even at atmospheric pressure, effectively bridging a significant gap in the literature where experimental investigation of mineral carbonation has not been extensively explored. The results of this work provide the petroleum industry with a reliable and safe approach for accelerated CO2 sequestration in various rock formations, thus enabling the companies to successfully meet their sustainability and decarbonization objectives.
State-of-the-Art Modeling Eliminates Drilling Dysfunctions in a Challenging Wildcat Ultradeepwater Wildcat Well
Authors: Batruny P. , Aguiar R. , Cruz R. , Barreto D. , Carbone G. S. , Shafei M. S. , Yusof M. S. , Aziz M. F. Abd , Monte T.
Published: September 2024

Operators have expanded their search for new oil and gas reserves to more complex and challenging environments such as the ultradeepwater, presalt carbonate plays offshore Brazil. The major challenge these wells have faced historically is the well cost overrun from low rate of penetration (ROP) and downhole tool nonproductive time (NPT) related to drilling dysfunctions. To avoid costly trial and error, advanced software was combined with service provider and operator experience to get it right the first time: improving ROP while minimizing damage to the bottomhole assemblies (BHAs), drilling each section on time and on budget.

An advanced 4D (spatial 3D + time) finite element transient drillstring dynamics modeling package is used to design the cutting structures, predict the drilling dynamics, evaluate different BHAs and drilling configurations, and optimize drilling parameters. BHAs for riserless, post-salt, salt, and silicified carbonate sections of the well are analyzed and optimized. Simulations are run to determine proposed BHA configurations and the potential for axial, lateral/torsional, and stick-slip vibration for different rock strengths. The BHAs are then optimized by adjusting cutting structure, stabilizer placement, hole enlargement ratio, and drillstring configuration. Once an optimum BHA is selected for each section, a sensitivity analysis is conducted on RPM, weight on bit, and torque to maximize ROP for each BHA.

Three criteria are used to evaluate BHA performance: stability, robustness/reliability, and measurement quality. The performance of each optimized BHA is compared to the performance of the base case BHA from offset wells. The accuracy of the model's simulations and the optimum recommended parameters is also examined against field results. Overall, the optimized BHAs delivered up to 50% higher ROP compared to the base case from offset wells drilling similar formations. In most cases, the optimum parameters recommended by the model were also the optimum parameters in the field test. The increased confidence in the model from the field tests enabled its use to optimize the BHA further for future wells.

This work presents a digital bit and drillstring design workflow, used to virtually run and analyze different BHA designs prior to running in the field. The work, tested in the field, resulted in multiple learnings shared in this paper, specifically in the realm of drilling mechanics.
Fostering Storage Integrity in Offshore Geological Hydrogen Storage Sites: Insights from Coupled Flow and Geomechanical Studies
Authors: Okoroafor E. R.
Published: September 2024

The primary objective of this study is to address storage integrity concerns associated with underground hydrogen storage in offshore porous media. The focus is on preventing losses caused by the cyclical nature of hydrogen injection and withdrawal. The study aims to anticipate the emergence of storage integrity problems by determining the response of various parameters, which encompass pressure, temperature, displacement, strain, stress, and fluid composition.

This study uses a synthetic reservoir model to explore diverse parameter responses across different phases of hydrogen storage and withdrawal. The investigation commences with a straightforward hydrodynamic numerical simulation model and progressively introduces complexities such as hysteresis, faults, thermal influences, and geomechanics. The values of pressure, temperature, displacement, strain, stress, and fluid composition are tracked at grid blocks that could be potential monitoring sites.

The findings of this study show that pressures are the initial indicators of potential non-sealing faults or fractures. The arrival of fluid through these flow conduits occurs at a later time. This delay in fluid arrival can allow for timely measures to be taken to prevent fluid loss if continuous real-time monitoring is in place. Monitoring above the injection well is suitable for gauging strain, stress, and displacement, as these perturbations reach their maximum levels above the injection or production area.

This study contributes novel insights into storage integrity during offshore hydrogen storage within porous media. By investigating various parameter responses throughout different stages of storage and withdrawal, the study introduces an understanding of pressure perturbations as early indicators of potential faults or fractures. Furthermore, the distinction between the timing of pressure perturbations and fluid arrival offers a valuable opportunity for preventative actions. The study also emphasizes the significance of monitoring location in relation to the leakage site for effective response detection. Finally, the practicality of monitoring above the injection well for specific perturbations is highlighted, enhancing the knowledge base for maintaining storage integrity.