bluuebunny/crossref_metadata_2025 huggingface dataset:
DeepStar Projects Impact on Industry Standardization
Authors: Gomes Joseph Vincent , Shamshy Shakir , Ostebo Runar
Published: April 2023

DeepStar® is an operator-funded Research & Development joint industry consortium including members of the oil community such as oil & gas companies, vendors, regulators, and academic/research institutes working in multidisciplinary technology areas. The DeepStar Project has been in continuous operation since its inception in 1991 and has focused on issues and technologies required to successfully tackle future development and production challenges identified by its members.1

The focus of this manuscript and extension, the presentation, will be on the numerous projects that were the baseline for current industry standards. The DeepStar program is split into six technical areas of focus from subsurface and drilling to topside and autonomous operations and everything in between. The manuscript will be written focusing on those technical areas and the supporting projects in which final documents are used within the standards.

The emphasis will be on three strategic areas of interest for our DeepStar members; first Integrity Management and the integration of our guidelines into the 1) API RP 2SIM Structural Integrity Management of Fixed Offshore Structures2, 2) API RP 2RIM Integrity Management of Risers from Floating Production Systems3 and 3) API RP 2 MIM Mooring Integrity Management.4 The second topic is DeepStar work on AUV interface standards5 and the integration of our work into API RP 17H6 and into the SWIG JIP.7 The final topic highlighted within the session on Standards is DeepStar’ continuous work on Subsea Chemical Storage and Distribution Systems Subsea8 to which DeepStar has developed the business case, background requirements, field case studies, and funding commercialization development on this topic since 2010.9

This manuscript outlines DeepStar’ strategies, projects, and accomplishments through a collaborative effort amongst operators, engineering firms, manufactories, academic intuitions, and government regulators. Through this joint effort, members have been able to minimize the cost and risk of industry-wide engagement and technology development, while at the same time making the most of the organization's particular technology achievements. This aligns with DeepStar’ vision for the development of deepwater technology, which is closely tied to the development and qualification of advanced technologies and gaining acceptance within the oil & gas community. DeepStar has continuously confronted industry-wide issues and provided a forum for discussion and technology acceleration.
Geotechnical Characterization of the US Atlantic Outer Continental Shelf Fine-Grained Cohesive Sediments
Authors: Long Xiaoyan , Fraser Jack , Adhikari Sudarshan , Hargrave Deanne , Peralta Proserpine , Scherschel Craig
Published: April 2023

An offshore geotechnical site investigation campaign was completed for a large wind farm development project along the US Atlantic Outer Continental Shelf (OCS) offshore New Jersey, a frontier location with few published data on soil characterization. Field exploration and a comprehensive onshore geotechnical laboratory testing program have been performed to understand the site-specific soil behavior. This paper describes the geotechnical properties of the fine-grained cohesive sediments encountered at the study site interpreted based on a consistent framework leveraging the sitewide soil data. Discussions of sample quality, soil stress history, soil compressibility and permeability, peak and critical state shear strength, strength anisotropy, and shearing rate effect for the Atlantic OCS fine-grained cohesive soils are presented from oedometer consolidation, permeability, direct simple shear, ring shear, and K0-consolidated triaxial compression and extension tests along with other conventional index and property tests.

Furthermore, the Stress History and Normalized Soil Engineering Properties (SHANSEP) parameters, namely S and m, for the cohesive soils, are developed based on the specific monotonic constant volume direct simple shear (CVDSS) tests. The undrained shear strength Su profiles within the specific geotechnical cohesive soil unit developed from the SHANSEP and SP-SPW methods (Quiros, 2000) is compared to the site-specific PCPT data and laboratory undrained shear strength measurements. Comparisons of the discussed engineering properties of the Atlantic OCS fine-grained soils with other published databases for soils of the Gulf of Mexico (GOM), Offshore Trinidad, and Offshore Mozambique also are included.

This paper is in a collaborative series that demonstrates the value of an integrated geoscience approach considering regulatory requirements and project design essentials. It provides a comprehensive overview of the engineering characteristics of the Atlantic OCS fine-grained soils and can assist engineers with the assignation of rate-dependant undrained shear strength parameters developed specifically for wind farm foundation design with applicability in a regional setting.
Offshore Integrity Management and Life Extension - A Vision of the Application of Subsea Robotics in Assuring Asset Integrity
Authors: Gower Andrew Stephen
Published: April 2023

The longer operating life of Oil and Gas fields presents challenges to the Risk Based Inspection methodology generally applied to subsea infrastructures once the operating life of projects approaches the original expected operating period or Design Life. For Life Extension, it is anticipated novel sensors or techniques will be required to mitigate the risk of infrastructure failure. There is a strong likelihood that additional requirements will be identified to conduct either an increased frequency of inspection of subsea infrastructure, or to benefit from the emergence of enhanced sensor technologies. Application of emerging sensor technologies (magnetometry, vibration analysis etc) increase the likelihood to detect equipment anomalies earlier.

Traditional inspection by video imaging with the application of additional sensors (e.g. contact CP, wall thickness) typically requires the use of a support vessel. Hence, the requirement of additional or prolonged inspection campaigns, would result in the unsustainable consequence of increasing exposure to risk, higher CO2 emissions and additional cost, while presenting a risk of increasing inspection backlog (more with the same).

There is a rapid emergence of technical solutions of vehicles as a sensor platform with enhanced robotics and autonomy. These solutions offer the opportunity to increase the frequency of inspection campaigns while reducing exposure to risk, CO2 emissions and offers opportunities to reduce inspection costs.

To be presented is the vision of the application of Subsea Robotics from a multi-energy operating Company perspective in assuring Asset Integrity in a Life Extension context. The Concept of Operations will be explored for Autonomous Underwater Vehicles, Remote Operated Vehicles, and duets with Uncrewed Surface Vessels. The challenges of operating in deepwater fields will be discussed also highlighting preliminary opportunities to provide transverse solutions applicable to the inspection requirements of the Offshore Renewable Industries.

Finally, the challenges of testing, qualification and acceptance of those emerging robotic technologies will be discussed to provide a conclusion.
Real Time Pore Pressure Calculation from Drilling Dynamics Data via Machine Learning Techniques
Authors: Reilly Matthew James , Thurmond John B , Chovanetz Koda F , Party J Mike , De Jesus Orlando , Unladi Muhlis
Published: April 2023

A method is proposed to calculate pore pressure at the bit while drilling using all data typically available in a modern drilling operation. This method utilizes a machine learning approach that can estimate pore pressures at the same or lesser range of uncertainty as traditional methods and can do so at the bit in real-time. Traditional pore pressure estimation while drilling utilizes a combination of data sources most of which are detected from logging while drilling (LWD) sensors placed 100's of feet behind the drill bit (where resistivity, sonic, density etc. tools are commonly placed). Furthermore, smoothing algorithms are often used to average the detection data thus increasing the offset from the drill bit to the estimated pore pressure calculation. The result of this is that the pore pressure calculation while drilling is only relevant to the formation that has already been penetrated and not being actively drilled. In hole sections where minor pore pressure changes can have significant impact on operational decisions this has obvious disadvantages. However, while drilling a well multiple sources of data from the drill bit itself are typically left unused in pore pressure calculation. Whereas traditional methods give an estimate of pore pressure after the well has already experienced a change in pressure, this method can calculate pore pressure at the bit, as the change is experienced. Another benefit of applying a machine learning model to pore pressure calculation while drilling is that the computational time is almost instantaneous.
Subsea Processing Systems: An Overview of Promising Technologies on the Subsea Factory Decarbonization Path
Authors: Basilio Leandro Pereira , Machado Priscilla Badega , Sousa Luara Katarine Silva , de Sousa Débora Calaza , de Castro Rafael Vinicius , dos Anjos Rodrigo Petrone , Andreotti Marcelo , Juliano Diego Russo , Chaney Carmela , Matos Sarah , Ryu Sam
Published: April 2023

The proper development of an offshore oil and gas field relies on a project's ability to deliver the maximum economic benefits while maintaining safety and environmental targets. In this sense, offshore oil and gas companies have continually evaluated ways to optimize system designs and streamline operations to ensure the achievement of these objectives. A set of technological alternatives that have been highlighted is subsea processing, which requires moving a processing system from the topsides to the seabed.

The assessment of subsea processing systems has become an important step during the field development strategy definition, especially in terms of flow assurance by mitigating hydrate and wax formation. When combined with mature subsea production technologies, the potential benefits of deploying subsea processing include enhanced reservoir recovery improved facilities availability, reduced topsides processing requirements, and reduced overall field development cost resulting in improvement of project economics. In addition, depending on the subsea architecture chosen, subsea processing can contribute to reducing the carbon footprint, which is in line with the industry's decarbonization goals.

Due to the potential benefits of the subsea processing architectures, new technologies are emerging to overcome the technical challenges to enable this transfer of strategic processes from the topsides to the subsea. The objective of this paper is to present and discuss the mapped subsea processing system archetypes that may significantly increase hydrocarbon production in a cost-optimized way for new fields, tiebacks, and operating facilities.

The mapped archetypes are implemented in an Expert System that integrates all technical areas for offshore field development, providing hundreds of conceptual alternatives to understand the impact of using subsea processing systems. This paper provides an overview of promising technologies that have the potential to increase the scope of subsea processing, leading to the identification of the most favorable architectures for each project.

This study incorporates a detailed analysis of 27 different subsea archetypes, combining processes such as liquid boosting to host, gas compression to host, two-phase and three-phase separation, produced water reinjection or disposal, seawater injection with sulphate removal, dense phase (natural gas or CO2) boosting to reinjection, gas dehydration, and gas compression. Such analysis indicated that equipment with different technological maturity levels can be combined to create a subsea processing arrangement that meets the project requirements.
Scenarios for Subsea Fields Decarbonization: A Mapping of Potential Power Schemes and Solutions
Authors: Delaplace Thomas
Published: April 2023

The objective of this paper is to map the potential levers available to meet the ambitious commitments taken by the Oil & Gas industry to reduce its environmental impact. This paper focuses on subsea developments and the offshore power solutions that may allow to reduce associated scope 1 & scope 2 GHG emissions.

As the usual power generation systems based on the use of gas or fuel turbines are a major source of emissions for offshore production, power generation and power sources represented an interesting field of investigations. A series of scenarios for subsea systems was defined, depending on the equipment to be powered (subsea trees, subsea processing, subsea compression…). On the other hand, a preliminary mapping of all potential power sources for an offshore field was built. Then, implementation of such power sources in various subsea schemes have been investigated and associated benefits, limitation and technology requirements have been discussed.

The presented paper allows to get a quick and quite comprehensive overview of the potential schemes to be investigated to decarbonize power generation for subsea fields. It can be used as a high-level guide to start decarbonization investigations for specific study cases, depending on the available resources and development objectives for the field.
A New Experimental Core Analysis Method for Formation Permeability Measurement Under Two-Phase Condition
Authors: Zhang Fengyuan , Zhang Qiang , Zhang Zhengxin , Rui Zhenhua , Liu Yueliang , Zhang Wei , Zheng Xiaojin , Torabi Farshid , Afanasyev Andrey
Published: April 2023

Experimental methods for core plug analysis are widely used to measure formation permeability under steady-state flow or unsteady state flow conditions, which provides important geoscience information on formation properties. However, typical laboratory techniques hardly reproduce the two-phase water and hydrocarbon storage and transport conditions that formation is subject to in reality. Accordingly, we presented an integrated experimental core analysis method for permeability measurement, which better reproduces these two-phase conditions.

The proposed experimental method consists of two-phase fluid initialization and production test, during which the gas rate, liquid rate, and inlet/outlet pressure of the core plug are recorded simultaneously. After constructing with uniform distribution of gas and liquid, the core sample is transformed into a two-phase production process under the conditions of variable rate and sealed boundary. Rate transient analysis is performed to estimate formation permeability with the gathered two-phase rate decline and pressure data. A two-phase diagnostic plot and specialty plot are introduced to identify flow regimes and extract permeability from the slope of a straight line during the experimental data analysis.

In this paper, commercial software is used to generate synthetic data for the production test of a core plug. The simulation of two-phase fluid initialization and production tests were conducted on core plugs. The simulation results show a unit-slope straight line on the generated diagnostic plot, which indicates a clear boundary-dominated flow (BDF) regime. By performing a straight-line analysis, we calculated the permeability of the core plug with the slope of straight-line period on specialty plot. The good match of the calculated permeability with the reference value confirms the accuracy of the proposed experimental method with the relative error less than 10%. In addition, the proposed two-phase core analysis method can enormously accelerate test-time, as the permeability of selected rock sample can be estimated in less than 10 minutes.

Instead of measuring permeability only under the condition of single phase flow, this paper presents a laboratory technique that combines the experiment of small-diameter core production test under two-phase flow with rate transient analysis method. Unlike prior experimental techniques, the proposed method reproduces the more realistic condition of two-phase flow in the formation during permeability measurement. The two-phase core analysis method achieves the objective of accurate and fast characterization of formation permeability, which is a more "apples to apples" comparison between the fluid flow in the actual reservoir and the core plug.
Highly Efficient Eco-Friendly Polyurethane Composites with Palm Fibers in Removal and Recovery of Oil Spills
Authors: Paredes Zaldivar Mayté , Pinheiro de Queiroz Guilhermo , Martins Wagner , Mulinari Daniella Regina , Silva Freire Paulo Cesar , de Souza Barbosa William , Vilela de Faria Giancarlo
Published: April 2023

This work aims to reveal the highly efficient performance of eco-friendly polyurethane (PU) composites with natural palm fibers in the removal and recovery of oil spills. In addition, it is shown that this composite allows oil recovery and reuse, and still the composite material reusability. The study was done from the composite material and mini sorption barriers, up to real scale barriers. The eco-friendly polyurethane-natural palm fibers residue composite foams were obtained by the partial replacement of petrochemical monomers with polyols derived from vegetable oils, and the addition of natural palm fiber residues. The initial tests were carried out in the laboratory using the composite material and mini sorption barriers with 0.3 m. The oil sorption capacity and the sorption efficiency in oil and water were studied using crude and used oils. Also, the oil recovery and the material reusability were tested. Additionally, the oil spill sorption and containment performance of real scale barriers, 3 m long, were tested at a swimming pool and at wave bay and river flow scenarios, respectively. The study showed that composite material exhibited higher efficient oil sorption capacity and recovery efficiency in water, reaching values of 20-26 g.g-1 and 85-99 %, respectively. This material still allows the sorption of the dissolved oil, been possible to observe the oily water clarification by the demulsification. Besides, it was possible to recover about 60 % of the oil and material reuse or recycling of at least 7 cycles. Also, efficient results were obtained for the mini sorption barriers. In the case of the bigger barriers, the tests also reveal high oil absorption capacity and that barriers are effective in the adsorption of oil spills. It was observed that the barriers absorbed almost 100% of the oil and maintained its buoyancy. The buoyancy remains greater than 46% after oil sorption. Then, we can conclude that the developed and patented eco-friendly polyurethane - natural palm fibers residue composite foams are excellent materials to be applied in sorption barriers, and these barriers are highly efficient in the removal and recovery of oil spills, also allowing the recovery of oil and the barrier reusability. The novelty is the introduction of efficient eco-friendly composite materials used in sorption barriers. This composite material was tested at the Centre of Documentation, Research, and Experimentation on Accidental Water Pollution (CEDRE), in France, certifying their efficiency and that the material can be recommended for use as a floating sorbent for oil pollution.
Broachment Studies Considering Fracture Propagation in a Well Containment Analysis
Authors: Cutrim Fabio Sawada , Azevedo Cecília Toledo , Baptista Renan Martins , Fernandes André Alonso
Published: April 2023

Well Containment Analysis – WCA - is a set of integrity analysis criteria in a shut in scenario performed during the well design phase. The installation of a capping and shut in of the well shall not induce hydrocarbon leakages to the seabed. One of the integrity analysis criteria within WCA is a situation in which the well, in a blowout scenario, is closed with the capping, and a fracture is then initiated at a specific casing shoe of the well, propagating through shallow formations. The analysis ensures that the time for fracture propagation to reach the mudline is longer than the time to drill a relief well and have the well controlled.

When considering a situation of a fracture propagation in a blowout scenario after capping and controlling the well there are two main possibilities: (I) a shallow reservoir can absorb the hydrocarbon flow from a deeper reservoir, (II) the time required for the fracture propagation to reach the seabed is greater than the time needed to control the well in blowout situation, guaranteeing that there is no fluid broaching to the seabed. When considering the time for fracture propagation, a safety margin is needed due to uncertainties in the geological data.

This work aims to present a few case studies where well projects didn’t attend WCA analysis considering P90 pore pressure scenario and needed further analysis to ensure attendance of well integrity. In this situation, studies were done considering fracture propagation beginning after the well closure due to a hypothetic blowout, trying to analyze if hydrocarbons would broach to the mudline, and if so, how much time such an event could occur.

Study results show the impact of geology and geomechanics on fracture propagation. There are situations in which the fracture remains confined due to the presence of a shallower reservoir and others where the fracture broaches to the mudline in a short amount of time.

This analysis has the potential to turn the concept of well integrity more flexible, allowing the well designer to combine, in a tentative optimal way, a safe and feasible design in more challenging scenarios.
Filtration of Biodegradable Fiber-Containing Drilling Fluids for Offshore Shallow Weak Formations
Authors: Takahashi Kazuma , Naganawa Shigemi , Bjarkason Elvar Karl , Mukai Ryutaro
Published: April 2023

Fiber-containing drilling fluids are expected to improve hole cleaning efficiency and have filtration properties that help to form a strong mud cake on the borehole wall. The objective of this study is to evaluate the filtration properties of drilling fluids containing a novel biodegradable polymer fiber.

The novel 100% bio-based polymer, named PHBH (TM), biodegrades easily in a seawater environment. The filtration properties of drilling fluids containing PHBH fibers were investigated through static filtration tests using an API (LPLT) filter press and a high-temperature and high-pressure (HPHT) filter press. The HPHT tests were conducted at 93°C (200°F). The tested base fluids contained 1.5wt% of bentonite or sepiolite clay, and 0.1 to 0.4wt% of polyanionic cellulose (PAC-HG) as a viscosifier. Sepiolite was considered since it is more thermally stable than bentonite.

From the results of API and HPHT filtration tests, adding 0.4wt% PHBH fibers reduced the amount of filtrate by approximately 5 to 7%, and the thicknesses of mud cake by approximately 24 to 34%. Among the 3, 5, 10, and 14 mm-long fibers tested, 14 mm long fibers resulted in the maximum reductions in filtrate and mud-cake thickness. Analysis of the solid concentration in the suggested that thin and strong mud cakes might form by adding the PHBH fibers for both bentonite- and sepiolite-based fluids.

Compared to the existing commercial fiber additives, the novelty of application of the new biodegradable fiber-containing drilling fluids to prevention of lost circulation or borehole wall strengthening in offshore shallow weak formations is highly environmentally-friendly for sustainable oil and gas developments. The biodegradable fiber-containing fluids can be applied in various uses like completion fluid, cementing spacer, etc.
The Challenges of Executing Pull in and Pull-Out Operations With ROV in Scenarios Designed For Shallow Divers Intervention
Authors: Santana Andre Bevilaqua Luiz Bevilaqua , Correa Ygor Fernandes Dos Santos Manhães , Da Silva João Luis Batista , De Oliveira Allan Carré Carre , Marino Lucas dos Anjos Cristino , Junior Roberto Alves de Lima , Giacomin Joelis Herminio , Barbosa Raquel Vila , Chargue Luciana Sa Silva Guillamet
Published: April 2023

Over the last few years, Petrobras has sought to reduce divers’ exposure to risk, as well as reduce this dependence on human diving in its underwater activities and reducing critical resources that impact underwater interconnections.

A subsequent de-risking phase of the principal technological gaps and critical engineering activities were structured to support a robust solution to be installed and validated in a full-scale prototype tool. All feasibility studies indicated the need development of tools that can be less impacted by the relative movements between floating platforms and ROVs (Remotely Operated Vehicle) in shallow water operations, allowing bellmouth preparation operations, for example.

This paper presents the challenges that Petrobras has been facing to perform the pull in and pull out of flexible pipes with ROV in scenarios made to operate with divers.
Through-Life Modelling of Rock Berm-Pipe-Seabed Interactions
Authors: Borges Rodriguez Antonio Alberto , Gaunt Peter Francis
Published: April 2023

This paper portrays salient features of the rock-berm pipe seabed interaction affecting the through-life axial restraint of rock berms installed intermittently over High Temperature High Pressure (HTHP) pipelines including: (i) axial displacement cycles of a pipeline leading to cyclic compaction of the soil and associated to this, downwards movement of the pipe and unloading of the rock berm-pipe contact. This is followed by a gradual re-gain in the system axial restraint by the process of (ii) cyclic soil hardening, and (iii) the process of ‘arch’ collapse promoted by the axially moving pipeline.

Earlier numerical studies (in Carneiro et al., 2017, Borges-Rodriguez et al., 2018) demonstrated unloading of the rock berm-pipe contact by ‘arching’ of the stresses in the rock berm as the pipe penetrates the seafloor. Observations of unloading of the rock berm-pipe contact and subsequently, of the axial load re-gain due to pipe movements, have been made in a suite of centrifuge physical model tests (in O'Beirne et al., 2022a, b). An analytical tool has been developed to capture these effects and is presented here.

More specifically, the model describes the evolution, in a cycle-by-cycle manner, of the axial restraint by the rock berm-pipe-seabed system, allowing the tracking of the axial restraint of the combined system across the operational life. Features of the analytical tool include the prediction of soil volume compaction and downwards displacement of the pipe with cycles, and of an initial and significant ‘drop-off’ in the axial resistance associated with the pipe penetration. The analytical model also reproduces the re-gain in system axial resistance that develops through the combined effects of soil hardening through the process of episodic shearing and re-consolidation, and by the pipe axial movements disrupting the force ‘arches’ set-up along the berm. The analytical tool has been calibrated through dedicated numerical analysis and the results of model tests in the public domain. The tool permits analysis of a range of pipe and soil properties and rock berm geometries and seabed materials. The tool's modelling of the arching phenomenon and post-arching recovery in axial resistance is through a sound theoretical framework. Hence, the analytical tool provides a robust basis for screening the concept of rock berm installation to manage pipeline axial end-expansion, buckle-to-buckle feed-in and arresting the walking propensity. Finally, and based on the demand for axial restraint, the tool can be used for form-finding of the berm for the accurate evaluation of rock volume requirements.
Application of Machine Learning Model for Estimating the Geomechanical Rock Properties Using Conventional Well Logging Data
Authors: Gabry Mohamed Adel , Ali Amr Gharieb , Elsawy Mohamed Salah
Published: April 2023

Building a geomechanical model for reservoir rocks is crucial for oil and gas operations. It is essential to solving multiple designs like wellbore stability for drilling operations, hydraulic fracturing, and sand production prediction for production operations. The best method to build a geomechanical model is to measure in the lab or calculate it from the dipole sonic log. However, it cannot be practically done routinely due to the high cost of logging and processing the dipole sonic logs.

With the training of a machine learning model using conventional logging data and dipole sonic logs and static geomechanical measurements in the lab, a machine learning tool is provided to predict the dipole sonic logs and build a geomechanical model using routinely recorded well logs like gamma-ray, resistivity, neutron porosity, and density. The calculated minimum horizontal stress was calibrated practically with the derived closure pressure derived from several diagnostic fracture injection tests.

This paper provides a practical implementation of a theory-controlled data learning model. It introduces an innovative way to build a calibrated machine learning tool that can predict shear and compressional wave velocities and estimate the rock mechanical properties using the regular conventional well logging data, which are helpful for oil and gas operations.
Methanol + Hydrogen - A Prospective Alternate Fuel for Cleaner Offshore Power Generation
Authors: Narayana Iyer Subramanian , Megaritis Thanos , Ganippa Lionel , Krishnamoorthy Harish Sarma
Published: April 2023

This paper analyzes the benefits of employing reciprocating engines to power offshore oil and gas (O&G) loads using methanol as fuel instead of (or mixing with) diesel that has been used conventionally. The study is carried out on a methanol-based single-cylinder, 50-liter, heavy-duty reciprocating engine for two test cases of power (30 kW and 111 kW) at different boost pressure and injection timing. In this investigation, 1-dimensional modeling and analysis using Ricardo Wave software was performed. Then, the effect of adding small amounts (<10%) of hydrogen into the engine in terms of performance improvement and emissions’ reduction is explored. Moreover, engine performance, indicated thermal efficiency, and CO/NOx emissions are compared for different boost pressure values at varied injection timing and constant power. The tests are carried out by modeling multiple use cases and comparing them, including (i) direct injection of methanol, and (ii) direct injection of methanol with port injection of hydrogen by spark ignition method. The addition of hydrogen with methanol results in a significant reduction in emissions and increase in the indicated thermal efficiency. Moreover, advancing the injection timing and increasing the boost pressure decrease the CO/NOx emissions, and also improve the indicated thermal efficiency. This paper presents these analyses in detail for multiple test conditions.
Wellbore Casing Integrity Envelope for Deepwater Reservoirs – Workflow and Case Study
Authors: Gandomkar Arjang , Pei Jianyong , Tjengdrawira Marius
Published: April 2023

It has been known that offshore wellbores are prone to experience large deformation due to compaction of the reservoirs during the field production life. The induced compaction results in undesired effects on wellbore integrity and reservoir performance. Wellbore diameter restriction, casing shear, and cement de-bonding are a few examples of such effects. Permeability/porosity losses and fault reactivation are major concerns for the reservoir performance. It is the utmost goal for any operators to ensure long-term safety and integrity of their fields and wellbores for economical and HSE purposes. This demands a complex planning and modeling that a classical 1D geomechanical workflow cannot provide. Complex numerical simulation workflows coupled with adequate engineering planning and design are required to estimate safe operational characteristics given a field and wellbore conditions. Operators can characterize the safe operational envelope in terms of depletion and drawdown pressures since the reservoir compaction is highly dependent on these parameters.

Several operators such as ExxonMobil have established their casing integrity evaluation throughout the lives of their fields either with analytical solutions, decoupled modeling by separating rock model from the casing behavior, or a sophisticated two-scale 3D finite element model (FEM) [3, 6]. It is believed that that the latter approach offers more in-depth understanding of the loading that may compromise casing integrity during production. This paper illustrates the necessary modeling components and workflow that is required to predict the safe depletion and drawdown pressure without compromising the integrity of a casing and re-activating any faults or fractures. ABAQUS 3D FE geomechanical modeling was coupled with the result of reservoir simulation to study drawdown and depletion effects. An FE submodeling technique was applied to account for formation, casing, and cement interactions. The technique will allow a fully coupled analysis using the boundary conditions established by the global (field-wide) 3D FE modeling. Any types of casing deformation modes (shear, tensile, buckling, and collapse) under in-situ stress changes due to depletion and drawdown, rock mechanical and fluid behaviors, and wellbore trajectory can be evaluated.

In this paper, a deviated deepwater wellbore is analyzed using the Casing Integrity Envelope workflow. Two sections of a wellbore prone to casing deformations, one above and the other inside the reservoir, are examined. The resulting drawdown and depletion envelope enabled the operator to plan actions to mitigate well failures and to ensure safe operations. In general, the developed workflow can be created for any field, casing/cement configurations, and environment. It incorporates coupling of various materials with complex boundaries which are the main advantages over the traditional analytical models.
Impact of Reservoir Salinity on Oil Recovery Using Surface-Modified Silica Nanofluid for Offshore Oilfield Applications
Authors: Kumar Ravi Shankar , Arif Muhammad , Kumar Sikandar , Sharma Tushar
Published: April 2023

Hydrocarbons (oil and gas) contribute significantly to the total global energy requirement, thus, oil recovery improvement from the current reservoirs is key. Nanotechnology based enhanced oil recovery (EOR) is a potential technique that can considerably improve the oil recovery factor. However, complex reservoir fluids which are highly saline (specifically in offshore) affect the stability of nanofluids and limit their efficacy through pore blockage during flow through porous media and offer a reduction in oil recoveries. This study thus proposes a novel technique for nanofluid formulation using different additives and surface-active agents and investigated them for stability in different techniques. Moreover, the formulated nanofluid is then tested for EOR in sand-pack experiments. The sand-pack is fully saturated using a NaCl solution; providing a realistic high saline laboratory model during flooding similar to an offshore environment. Various studies involving the stability and viscosity of nanofluids, and efficiency for EOR for offshore reservoirs have been reported. The efficiency of the nanofluid systems for stability, rheologicalproperties, and EOR has also been compared with the conventional nanofluid and newly formulated nanofluid flood schemes. This study reports that the saline environment severely damage the nanofluid stability by reducing electrostatic repulsive forces (screening electrical charges of NPs), subsequently, quick settlement of NPs was observed. The agglomeration and sedimentation of NPs within the nanofluids generally reduces the cumulative oil production by permeability impairment. However, the inclusion of surface active agents (surfactant) re-establishes the physical stability of the surface coating mechanism which curtailed the effect of salinity, especially in offshore oilfields. The surface-coated NPs in the nanofluid enhanced stability for a prolonged duration by maintaining nanometer size which is crucial to avoid early particle aggregation thus demonstrating incremental oil recovery in offshore oilfield applications. This study discusses the novel fabrication methodology of stable nanofluids using colloidal aspects for offshore oilfield applications where formations salinity becomes a major challenge during flow through porous and permeable media.
Scalable Geothermal Energy Potential from Sedimentary Basins and Leveraging Oil and Gas Industry Experience: Case Studies from Texas Gulf Coast
Authors: Vivas Cesar , Salehi Saeed , Nygaard Runar , Rehg Danny
Published: April 2023

Geothermal energy has the potential to be a dependable source of power in the future. However, its development has mostly been limited to specific geographical areas or types of rocks. The western US has relatively high downhole temperatures compared to other regions, however, similar temperatures could be found in other regions by drilling deeper into sedimentary rocks. The oil and gas industry has developed highly efficient and cost-effective methods for drilling in sedimentary basins. The main challenge is adapting these wells for geothermal energy production. When comparing the cost per foot of drilling in typical sedimentary basins to drilling in granite or igneous rocks, there is a significant cost saving for the geothermal industry. Furthermore, techniques for hydraulic fracturing used in the oil and gas industry can also be applied to geothermal energy production.

A prospective way to increase the production of geothermal energy is to utilize known reservoir rocks with storage and flow capacity that allows water or steam cycling in sedimentary basins. These rocks have the appropriate temperature, thickness, porosity, and permeability and are located at depths that do not make the drilling costs too high for the system to be economically viable.

This study will explore the unique advantages that Texas's sedimentary basins can bring to the geothermal industry, including electricity generation and direct heat utilization. Some regions of the Texas Gulf Coast have medium-high geothermal gradients, providing the potential for geothermal energy development. Texas's numerous oil and gas wells can support geothermal direct-use projects, as demonstrated by case studies. An analysis of the levelized cost of energy using geothermal gradient data suggests that there are areas with the potential to produce geothermal power at a cost of 14 cents or less per kWh. Geothermal energy has the potential to significantly contribute to Texas's energy supply by providing a clean and renewable source of power to meet energy needs.
Estimation of Shear Wave Velocity Using Empirical, MLR, and GEP Techniques-Case Study: Kharg Island Offshore Oilfield
Authors: Zamani Ahmad Mahmoudi Mohammad , Khalilidermani Mitra , Knez Dariusz
Published: April 2023

Determination of the shear wave velocity, Vs, is an integral part in creation of reservoir geomechanical models. This parameter together with the compressional wave velocity and rock density are utilized to calculate the dynamic elastic moduli of the subsurface formations. In well logging, the Vs can be directly measured through the Dipole Shear Sonic Imager (DSI) logs which need special requirements and technical considerations. Therefore, many researchers have strived to develop cost-effective accurate methods for Vs estimation in the oil/gas fields. The Kharg Island offshore oilfields, located in the Persian Gulf, consist of a giant limestone reservoir called Asmari formation. In the past, numerous studies were conducted to develop mathematical relations for Vs prediction in the Asmari reservoir; however those relations were not capable of estimating the Vs values correctly. In this research, the well logging data related to a vertical offshore well was utilized to develop three mathematical relations for Vs estimation in the Asmari formation. To do this, linear regression (LR), Multivariate Regression (MLR), and Gene Expression Programing (GEP) methods were applied. Moreover, the accuracy of those relations was compared with some available empirical correlations for Vs prediction in limestone rocks. Comparing the results of those data-driven equations with the empirical equations illustrated that the results of the GEP method are more accurate than other equations. Moreover, the Pickett empirical correlation was found to be more suitable than other empirical correlations for Vs estimation in the Asmari reservoir. The methodology applied in this research is a reliable procedure to estimate the Vs in the study area as well as other geologically similar oil reservoirs. Such an application leads to generation of robust geomechanical models increasing the project success and oilfield development progression.
Understanding the Gulf Ocean System Program: Informing Stakeholders and Improving Prediction of the Loop Current System Using Advanced Observational and Numerical Tools
Authors: Knap Anthony , DiMarco Steven , Glenn Scott , Ramos Rafael , Magnell Bruce , Salas David
Published: April 2023

Objectives/Scope: This paper describes a program funded by the National Academy of Sciences, Engineering and Medicine (NASEM) that follows up on 2 (3-year) programs to better predict the behavior of the Gulf Loop Current and its associated eddies, which in some years create havoc to Offshore Technology Industries and activities in the Northern Gulf of Mexico. The aim is to inform and integrate with Stakeholders for new and better products and agreed metrics to provide better tools for the end-users in the Gulf of Mexico. In recent years, 2015 and 2021 there were significant ocean current extremes that had major effects on the offshore industry which were difficult to predict and caused huge financial losses to offshore operations in the Northern Gulf of Mexico.

Methods, Procedures, Process: Using data from remote autonomous vehicles such as surface drifters, profiling floats, ocean buoyancy gliders, wave powered vehicles, fixed bottom moored acoustic systems, a Topographic Rossby Wave array and a series of coastal fixed High Frequency radars new models will be developed to predict Loop current dynamics, eddy shedding and reabsorption. In addition, data collected will be used to determine upper ocean heat content and its role in prediction of hurricane intensity forecasts. The program has a strong group of Private/Public stakeholders and we are hoping to get wider involvement in this program to deliver the best and most timely information to end-users in the Northern Gulf of Mexico.

Results, Observations, Conclusions: In total NASEM has funded a $40 million research program that will improve prediction, improve human well-being and improve offshore safety, and that the program seeks to understand (in this context) what the end user community needs are, to provide the foundation for continued dialogue and to provide a model for future private-public partnerships between scientists, agencies, and industry.

Novel/Additive Information: We believe that this program is unique as it relies on the involvement of industry and agency stakeholders at the beginning of the program so the observing systems and models can be co-designed and tailored to the recipient needs, not the other way around with has generally been the norm in the past.
Relative Viscosity Model for Water-In-Oil Emulsion in Electrical Submersible Pumps: Comparing the ESP Head in a Real Scenario
Authors: Bulgarelli Natan Augusto Vieira , da Silva Lucas Rodrigues Guedes , Biazussi Jorge Luiz , Monte Verde William , Melchuna Aline , Arinelli Lara , Silveira Thaís Márcia , Castro Marcelo Souza de
Published: April 2023

Emulsions are common during oil production, and this is the case of the Peregrino field, e.g. . In several fields, oil and reservoir fluids can be produced through Electrical Submersible Pumps (ESP) and the formation of emulsion affects the ESP system, its run life, and the production itself. The viscosity increase due to emulsion formation severely hampers the ESP performance, requiring an increase in energy consumption on the platform to keep the same production rate. This work presents an initial validation of the model proposed by Bulgarelli (2021) to predict the water-in-oil emulsion effective viscosity within the ESP and its impact on lift capacity. The model can aid the design of the ESP system and can be used as a flow rate estimation tool during ESP production. The initial validation was performed using data from water-in-oil emulsion production of the two wells (A and B) in the Peregrino field, which use two different ESP models. The validation was divided into two parts: the first corresponds to Technology Readiness Level (TRL) 3 and the second, TRL 4, according to ISO 20815:2018. Firstly, well tests data were used to calibrate and test the model for initial validation of the TRL 3. Operation data of these two wells were then used for the initial validation of the TRL 4 in the second part. In the first step, measured and predicted ESP head were compared. Mean Absolute Percentage Errors (MAPE) of 3.6% and 0.8% were obtained for Wells A and B, respectively. In the second part, both the measured and predicted ESP dimensionless head and the measured and predicted differential pressure were compared. From these comparisons, promising results were observed for both wells' operations. However, more oil data field is necessary to complete the TRL 3 and TRL 4 validation.
Using the Pugh Method to Select a Polymetallic Nodule Vertical Transport System
Authors: Barr Aaron M
Published: April 2023

On the sea floor of specific deep ocean environments lie prolific amounts of polymetallic nodules that contain minerals critical to meeting the future energy demands of a growing worldwide population. Polymetallic nodules rich in manganese, nickel, and cobalt spread over millions of square kilometers of abyssal seabed and contain the minerals needed for future energy storage demands. The offshore oil and gas industry seeks to participate in the energy expansion by leveraging its deepwater experience to harvest these nodules. The knowledge and wisdom gained from decades of operating offshore provides significant insight into the development and implementation of the technology needed to address the challenges of deep sea nodule harvesting.

The authors describe a design selection tool based on the methods described by Stuart Pugh to select a polymetallic nodule Vertical Transport System. Stuart Pugh, known for his work in product design and development, introduced the Pugh Method in the 1980s. The Pugh Method is a structured and integrated process applied to design development including concept generation, evaluation, and selection. The Vertical Transport System design processes uses the Pugh Method to recommend a candidate design. The evaluation step uses a two groups of company experts who present the concepts (the team), and collectively evaluate (the group) and recommend the best design concept for further development. We apply the method to the case of deep sea mineral recovery operations specifically the design of the Vertical Transportation System. First, the authors introduce the Pugh Method tool, how it works, and how it applies to this specific case. We describe how risks and rewards relate to each selection characteristic used to evaluate the Vertical Transport System concepts. Further, we talk about team selection and the points to consider when assembling the right team to achieve credible results. Next, we describe each concept identifying and recognizing the various technical, operational, and economic selection characteristics, such as size, power consumption, reliability, availability, etc. Finally, we evaluate each concept against the different selection characteristics and discuss the results. The paper concludes with a robust process flow chart describing the selection method for a Vertical Transport System.