bluuebunny/crossref_metadata_2025 huggingface dataset:
Solving Decommissioning and Abandonment Problems When Planning to Shear 9 5/8-inch Casing in a 13 5/8-inch × 10k RAM BOP
Authors: Cain David Earl , Klopfenstein Keith Albert , McMullan James Robert
Published: August 2021

A decommissioning and abandonment requirement to shear 9 5/8-inch casing in certain circumstances with a 13 5/8-inch × 10,000 psi rated working pressure, RWP, Shear RAM type blowout preventer, BOP, resulted in a need to develop a novel casing shear device and shear calculation method. Results of shear testing, future engineering planning guidance, the new shear calculation method, and comparison to legacy technology are included in this paper.

Interaction with the end user to understand requirements, a five-step problem solving procedure, a basis of design process, materials justification, verification analysis, validation testing, and describing an improved shear operator force/pressure calculation are all described. Shear larger casing in the required and restrictive RAM BOP and well bore presented a problematic challenge. Equally, tubular fish size was required to support fishing extraction operations following shear. Validation test results exceeded requirements and resulted in the need for a new approach to the shear calculation method.

The novel shear RAM geometry was developed utilizing shear calculation methods which were based on legacy considerations. API 16A shear validation procedures and two legacy shear calculation methods where employed. Shear calculations are used to anticipate the RAM BOP operator pressures required to shear a specific tubular. The larger than historically allowed casing size to be sheared in a 13 5/8-inch × 10,000 psi RAM BOP meant higher operator pressures were anticipated for each operator option. A Novel shear RAM geometry was developed as a design intent to lower shear force/pressure. There was an observation during validation testing that the geometry exceeded expectations to lower shear pressure significantly. This observation led to a conclusion that an improved shear calculation method was required for this application. This novel calculation method description / statistical treatment, test results, RAM design methods, and tabular shear engineering planning information are included in this paper.

One additional requirement of the shear RAM geometry was to provide an upper and lower fish deformed surface which could be easily retrieved thru the 13 5/8-inch BOP bore. An additional observation was that the fish width requirement was achieved.

The novel shear calculation method allows an engineer to precisely plan for bonnet actuation pressures when larger casing is sheared. The precise calculation of shear force/pressure also assists with BOP operator size and type selection. The engineer will gain casing size versus shear pressure for specific operator options in tabular format. Planners will gain insight into tubular fish deformation estimation allowing mitigation of tubular extraction risk during operations planning.
Predicting Porosity and Water Saturation from Well-Log Data Using Probabilistic Multi-Task Neural Network with Normalizing Flows
Authors: Lee Jinwoo , Kwon Minsu , Hong Youngjun
Published: August 2021

In the oil and gas exploration process, understanding the hydrocarbon distribution of a reservoir is important. Well-log and core sample data such as porosity and water saturation are widely used for this purpose. With porosity and water saturation, we can calculate hydrocarbon volume more accurately than using well-log solely.

However, as obtaining core sample data is expensive and time-consuming, predicting it with well-log can be a valuable solution for early-stage exploration since acquiring well-log is relatively economic and swift. Recently, numerous studies applied machine learning algorithms to predict core data from well-log. To the best of our knowledge, most works provide point estimation without probabilistic distribution modeling.

In this paper, we developed a probabilistic deep neural network to provide uncertainty via confidence interval. Besides, we employed normalizing flows and multi-task learning to improve prediction accuracy. With this approach, we present the model's uncertainty that can be reliable information for decision making. Furthermore, we demonstrate our model outperforms other supervised machine learning algorithms regards to prediction accuracy.
Development of Design Criteria and NDE Method for HPHT Equipment
Authors: Pathak Dilip Parth , Padmanabha Kishore , Wilhelmi Robert Joseph , Coutinho Luiz Henrique Velloso , Vampati Veera Venkata Rao Brahmaji
Published: August 2021

Subsea production systems have been using API-specified methods and detection criteria for nondestructive examination (NDE) for equipment up to 15,000-psi rated working pressure. With higher pressure requirements and use of methods for evaluation of the fatigue life of HPHT equipment, existing criteria cannot be sufficient to achieve the desired fatigue life. This paper demonstrates more stringent design criteria and a detection method that was developed to achieve HPHT fatigue life, yet is cost and schedule effective.

When fracture mechanics was used for fatigue life estimation, an initial flaw size is stated as a starting point in determining design life. Using API-specified NDE criteria of 1/16-inch detection of surface flaw, project design life was not achieved for certain components without a major redesign and retest. Smaller flaw lengths were preferred in critical areas instead of standard flaw sizes. This created a need for a high-sensitivity penetrant inspection technique to effectively detect this new minimum flaw size in critical areas. Various methods of NDE were considered, and a conclusion was taken in selecting the best inspection method.

Fracture mechanics and finite element analysis required a minimum detectable flaw size length of 1/32 inch to meet the project design life without changing equipment technology. By using surface NDE with fluorescent liquid dye penetrant of sensitivity levels 2 and 3, all seeded flaws of 1/32-inch were consistently detected in the validation test coupon, which enabled the use of this stricter criteria for the analysis. Detailed procedures were established, and validation testing results were documented with photographs of detected flaws. Seeded flaw coupons were manufactured for validation of procedures and to train the various facilities that will use these techniques for production equipment. Additionally, procedures and guidelines were provided to inspectors and inspection facilities to ensure proper implementation of the methods. Measurement system analysis for repeatability and reproducibility was conducted at the facilities. This enabled the fatigue design of the HPHT equipment to advance beyond the boundaries of traditional methods and acceptance criteria set by current industry standards.

New and tighter acceptance criteria were developed to improve HPHT fatigue life. High-sensitivity penetrant inspection technique, capable of detecting flaw sizes as small as 1/32-inch, was established and implemented. This inspection technique is not common to the oil and gas industry because of the ability of standard methods to readily detect the API-required criteria. The method has improved detection capabilities and has the potential to move toward adopting advanced design methods to address HPHT requirements.
Real-Time Digital Chemistry Offshore Transforms Flow Assurance Management
Authors: Lovell John R. , Kulbrandstad Omar , Madem Sai , Meza Daniel
Published: August 2021

Managing asphaltene accumulation in offshore Gulf-of-Mexico wells is a significant challenge. Until recently there was no real-time chemical monitoring that could advise on whether chemical inhibition was making a particular well more, or less, stable. This changed with the development of real-time hardware that directly measures the ratio of asphaltene flowing in the oil. A new generation of that hardware has now been launched which meets all of the Qualification and HSE requirements for deployment on offshore platforms.

A microwave resonator was designed to receive fluid at wellhead conditions, i.e., without a reduction in pressure or temperature, and the parameters of that resonator were optimized to maximize microwave intensity for typical oilfield fluids. The microwave circuitry is incorporated in an explosion-proof container with Class 1 Div 2 rated electrical and fluid connections. By combining that resonator with a solenoid that can generate a large magnetic field around a flowline, the resulting device resonates electrons within asphaltene molecules to create a unique signature that is proportional to the total asphaltene count. Estimates of oil-water cut and gas-oil ratio are also obtained as part of the processing and this combination gives the percentage of asphaltene within the oil. The use of this hardware with controlling software and cloud processing creates a unique Internet-of-Things device which can be used to optimize asphaltene-related flow assurance challenges offshore.

Pressure testing up to 5ksi and 120C gives the device a working envelope well exceeding typical offshore production hardware requirements. For a fixed fluid, the computation of asphaltene ratio was shown to be independent of applied pressure. Conversely, it was found that in a live well chemical properties of fluids can change over the course of a few hours even when the surface pressure and flow-rates stay the same. In one well, the surface asphaltene percentage within an oil was seen to vary from 0.3% to 3% because of alternating deposition and erosion of an asphaltene layer that had been forming along the ID of production tubing. Over the course of a series of tests in the Middle East, it was observed that those wells with uniform asphaltene percentage were seen as less troublesome to manage compared to wells with a higher deviation. In two Permian fields subject to CO2 flooding, a geographic variation in asphaltene percentage which correlated to the long-term exposure to injected gas was observed.

It has long been standard for chemical properties of fluids to be obtained by sending samples to a lab. This paper demonstrates additional value that can be obtained from getting that data in real-time, especially when viewed in the context of an overall chemical management program.
Deepwater Riser & Mooring Life Cycle Digital Integrity Management
Authors: Renzi David , Nadathur Varadarajan , Wong Steve , Zhang Michael , Chen Yong , Zarate Luz , Fan Shejun , Ayewah Daniel , Chakraborty Ishita , Kucukcoban Sezgin , Mistric Matt , Kurrus Keith
Published: August 2021

API SC2 has issued integrity management recommended practices to compliment the planning, design and construction standards that has led to a GOM installed base of 50 floating production facilities. Integrity management involves risk-based inspections in which the collection and analysis of characteristic and conditional data determines if integrity can be assured. The challenge to manage unstructured data with the same design and construction approaches yields inefficient and repetitive activities that can be time-consuming and may lead to a less optimal outcome.

The primary objective of the study is to understand the benefits of utilizing a digitized IM approach which involves high resolution metocean data to determine fatigue damage accumulation for tendons and risers instead of traditional design/assessment methods that use condensed metocean criteria data.
Autonomous Subsea Field Development - Value Proposition, Technology Needs and Gaps for Future Advancement
Authors: Arcangeletti Giorgio , Mattioli Matteo , Ausborn Mark , Matskevitch Dmitri , Marcotulli Amedeo
Published: August 2021

With increasing demand of subsea processing and surveillance goals Best-in-Class Operators are developing advanced subsea instrumentation and controls to challenge in the next decade: i) a cost-effective way to inspect and repair subsea complex facilities and ii) to reduce the downtime, possibly increase the production performance while preserving the integrity and maintenance of the assets.

The so called "Autonomous Subsea Field Development" is a study triggered by an ExxonMobil URC (Upstream Research Company) initiative aimed to explore possible improvements and re-designs of subsea equipment considering the advancing capabilities of ROVs and new generation of Subsea Drones, and driven by the following questions:

with the advancements in AUVs and ROVs, can subsea equipment be re-designed to take full advantage of the new capabilities? Can this re-design improve from different perspectives (Availability, Costs, Operations, etc.) a subsea field development?

A dedicated study was conducted by SAIPEM to identify the value proposition, technology needs and gaps for future advancement by leveraging on the technological "building blocks" that could be integrated in a subsea field development scheme and on a field operational procedure.

Within the study, seven different cases, distinguished by their status of advancement (from Brown to Green Fields) and by the level of penetration of Subsea Drones in the architecture, have been analyzed.

A conceptual engineering process, based on the tenets of value engineering was conducted in a holistic fashion covering the full field development facilities during the life cycle in order to steer the conceptual engineering choices that could maximize the project value.

Using a systemic Value Engineering approach based on the NPV equation, the study identified the main technological and economic impacts coming from the adoption of Subsea Drones on a current and future Digital Subsea Field exploring the following pillars: i) CAPEX, ii) OPEX, iii) AVAILABILITY, and iv) RISK.

In the sequence of six cases investigated, it has been identified how these incoming "subsea capabilities" will be gradually implemented into redesigned subsea architecture and serviced in view of a new Life of Field concept.
A Critical Assessment of Deepwater Gulf of Mexico Floating Platform Engineering, Procurement, Construction and Installation EPCI Contracting Strategies and Cycle Times
Authors: D'Souza Richard B. , Basu Shiladitya
Published: August 2021

A major objective of a greenfield deepwater field development with a host platform, is to achieve the first production milestone set at project sanction. A field development consists of subsurface characterization, reservoir depletion, drilling and completion, subsea production system, host platform and export system. Of these, the floating host platform is a major capital expense and presents a significant execution challenge. Over fifty deepwater floating platforms have been installed in the US Gulf of Mexico (GoM) since 1986, representing the four major platform options; spars, semisubmersibles, Tension Leg Platforms (TLPs) and Floating Production Storage and Offloading (FPSO) platforms, operated by International, Independent and National Oil Companies. They are installed in water depths ranging from 500 m to 3,000 m, with production capacities from 40,000 to over 250,000 barrels of oil equivalent per day (boepd). Over this period the technologies, operator, and supply chain capabilities to execute deepwater projects have matured.

An operator embarking on a deepwater project must credibly benchmark cycle times for sequential field development stages (Appraise, Select, Define and Execute). Many variables determine these cycle times including reservoir characterization, fluid properties, estimated recovery, location, access to pipeline networks, water depth, subsea architecture, platform size and complexity and contracting strategy.

To provide these benchmarks, the authors have undertaken a critical assessment of ten recent, producing deep and ultra-deepwater field developments in the US GoM, focusing on project execution of the floating platform. Selected field developments capture all floating platform types, several contracting strategies, a wide range of water depths, various reservoir geologies and field locations that cover the entire GoM. The information is intended to assist operators validate cycle times when planning a development, especially the Execute stage.

In addition, the paper addresses emerging trends in deepwater GoM field developments following the oil price collapse in 2014 and 2020.
Experience with Chemical Injection and Umbilicals in Pre-Salt Fields
Authors: Da Silva Sidnei Guerreiro , Gonçalves Andre Athayde , Da Silva William Albuquerque , Filho Rafael Di Lorenzo
Published: August 2021

The characteristics of Pre-Salt carbonate reservoirs demand downhole chemical injection to prevent scale, asphaltene, and wax deposits, besides the need of H2S scavenger, and MEG, normally injected at Xmas tree (WCT). The poor performance of injection systems installed in Santos Basin, together with production risks associated to the lack of chemical injection, led the project team to re-evaluate design requirements, such as chemical products characteristics, production systems equipments, umbilicals, and chemical injection valves. In addition, umbilical failures are being observed in other deep-water fields, related to subsea control systems functions. This paper focuses on Company operational experience and lessons learned related to umbilicals and downhole chemical injection.
Improving the Fatigue Performance of Welded Tubular Connections via Flared and Thickened Pipe Ends
Authors: Mansour Ghiath Guy
Published: August 2021

Fatigue is a primary challenge in the design of steel catenary risers (SCRs) and different measures and methods are utilized to mitigate it. Traditional upset ends and steel lazy wave risers (SLWRs) are such methods to mitigate fatigue.

SLWRs were first used in 2009 on the Espirito Santo floating, production, storage, and offloading (FPSO) vessel of Shell Company's Parque das Conchas (BC-10) project offshore Brazil. SLWRs have been used increasingly since then and gained popularity especially in recent years.

A novel patented tubular connection assembly referred to as Flared Thickened Ends (FTEs) improves the fatigue life of SCRs and welded connections in general. This novel assembly has many advantages. It overcomes the thickness limitation of welding traditional upset ends and reduces offshore welding time, cost, and risk.

When FTEs are used in simple SCRs, they render simple SCRs a robustly viable alternative at significantly lower cost, shorter schedule, and with many additional advantages as compared to SLWRs. Of the many advantages, simple SCRs are more straightforward to configure, analyze, design, and install using varied installation methods and vessels. Simple SCRs use less materials and offer better long-term integrity, especially for insulated SCRs. In addition, they have a smaller footprint and are less prone to clashing than SLWRs.
Development of Perforating System for Unique HPHT Injection Application
Authors: Grove Brenden , MacGillivray Joseph , Cook Jason , Hoelscher Chris
Published: August 2021

An operator was developing a High-Pressure High-Temperature (HPHT) field in the U.S. Gulf of Mexico (GOM). Completion design for the injector wells was cased-and-perforated, with no mechanical sand control. This led to the requirement for a tubing-conveyed perforating (TCP) system, featuring deep-penetrating (DP) charges which would meet specific performance requirements, in order to enable the wells to achieve injectivity targets.

A perforating system was therefore developed and qualified to meet these requirements. This was an integrated system development, including both mechanical and explosive components, with simultaneous attention to performance, reliability, and quality assurance in the eventual field environment.

The development program yielded a 4-3/4-inch carrier system, perforating charges, firing head, and gun hanger. All key components and systems were qualified in customer-witnessed testing, and demonstrated to meet or exceed operational function and performance requirements.

The pressure and temperature rating of the newly-developed system is 30,000 psi at 425 °F. Explosive train function reliability was demonstrated at 380 °F for up to 28 days. The newly-developed perforating shaped charge was confirmed to exceed the stringent penetration depth and casing hole diameter performance requirements at downhole conditions. The firing head offers operational flexibility by being configurable for up to 15 pressure cycles prior to detonation, with an adjustable initiation threshold pressure to reduce risk to the completion string. The gun hanger was customized and demonstrated to exceed load requirements, and reliably set and release, in a test configuration featuring operator-provided field casing.
MultiResU-Net: Neural Network for Salt Bodies Delineation and QC Manual Interpretation
Authors: HajNasser Yesser
Published: August 2021

Accurate delineation of salt bodies is essential for the characterization of hydrocarbon accumulation and seal efficiency in offshore reservoirs. The interpretation of these subsurface features is heavily dependent on visual picking. This in turn could introduce systematic bias into the task of salt body interpretation. In this study, we introduce a novel machine learning approach of a deep neural network to mimic an experienced geophysical interpreter's intellect in interpreting salt bodies. Here, the benefits of using machine learning are demonstrated by implementing the MultiResU-Net network. The network is an improved form of the classic U-Net. It presents two key architectural improvements. First, it replaces the simple convolutional layers with inception-like blocks with varying kernel sizes to reconcile the spatial features learned from different seismic image contexts. Second, it incorporates residual convolutional layers along the skip connections between the downsampling and the upsampling paths. This aims at compensating for the disparity between the lower-level features coming from the early stages of the downsampling path and the much higher-level features coming from the upsampling path.

From the primary results using the TGS Salt Identification Challenge dataset, the MultiResU-Net outperformed the classic U-Net in identifying salt bodies and showed good agreement with the ground truth. Additionally, in the case of complex salt body geometries, the MultiResU-Net predictions exhibited some intriguing differences with the ground truth interpretation. Although the network validation accuracy is about 95%, some of these occasional discrepancies between the neural network predictions and the ground truth highlighted the subjectivity of the manual interpretation. Consequently, this raises the need to incorporate these neural networks that are prone to random perturbations to QC manual geophysical interpretation. To bridge the gap between the human interpretation and the machine learning predictions, we propose a closed-loop-machine-learning workflow that aims at optimizing the training dataset by incorporating both the consistency of the neural network and the intellect of an experienced geophysical interpreter.
Subsea Chemical Storage and Injection- Qualification of HAMPRO 70V Pump
Authors: Thorkildsen Brede Andre , McKenzie Lachlan James , Følkner Stein , Pasquet Francois-Xavier , Bibet Pierre-Jean
Published: August 2021

The development of Subsea Chemical Storage & Injection (SCS&I) technology is a continuation of the trend to move more of the hydrocarbon production systems subsea. This is driven by a need to make exploitation of remote resources profitable; unlock single-line long tie-backs and subsea to shore architectures, and to enable tie-ins with otherwise constrained topside infrastructure. The SCS&I System is also a significant contributor to the development of "All-Electric" subsea architecture where the umbilical is reduced to a power and communication cable only.

TechnipFMC https://www.technipfmc.com/ and Total https://www.total.com/en are collaborating to develop and qualify the SCS&I technology components and system.

In order to make the SCS&I technology competitive and field developments profitable, the reliability of the equipment is paramount. The HAMPRO 70V injection pump is one key component in the system for which high reliability must be ensured.

The objective of the qualification program is to confirm the adequate performance of the HAMPRO 70V pump in the following areas:

The reliability of the chemically exposed parts and the impact of chemical fluid cleanliness The reliability of the pump and motor rotating parts and the impact of lubricant performance The reliability of the electrical components The impact of transient behaviour on the pressure compensation system, rotating parts and electrical components

Due to the similarity of design, smaller versions of the HAMPRO pump will also be qualified by the activities in the program.
Four Point Bend Test of 5LPP – Concrete Coated Pipe
Authors: Mathakari Sachin Vijay , Cox Cameran , Rattenbury Phillip
Published: August 2021

The objective of this paper is to present a 4-point bend test of 5LPP (Five Layer Polypropylene) concrete coated pipe. This is the first of its kind of bend test for a complex coating combination of 5LPP and concrete layers. The bend tests have been carried out to simulate S-Lay installation loading conditions to assess the coating integrity of the pipeline during installation. This paper reports the test arrangements including instrumentation, load schedule, test procedure and the challenges involved. Finally, the preliminary results and conclusions of the tests are documented.

Two separate full scale four-point bend tests are carried out to study the behavior of the 5LPP concrete coated pipe. The purpose of the first test is to understand the complex behavior of the 5LPP/CWC coated test pipe and validate previously made industry standard assumptions regarding the calculated coated joint stiffness. The purpose of the second test is to observe the coating integrity of the test joint and slippage behavior due to the simulated installation conditions (overbend and sagbend bending moments and/or corresponding curvatures). The nonlinear moment-curvature for the concrete coated pipe is estimated based on an analytical approach taking into consideration plane bending theory and slippage behavior of the coating layers. The moment-curvature is used to prepare the load schedule for the tests. The test string consists of a test joint (40ft) welded to half joints at the ends. The bend test is performed using industry established full scale 4-point bend test arrangements.

A global finite element model is used to simulate the tests using the analytical moment-curvature of the concrete coated pipe. The stiffness of the test pipe is calculated using the first bend test and compared against the analytical stiffness. The second test is carried out by applying loads corresponding to an estimated maximum overbend bending moment and then the test string is unloaded and rebent in opposite direction by applying loads corresponding to an estimated maximum sagbend bending moment. The results of the second test are documented at each load step and the integrity of the coating is measured against specified concrete coating damage criteria for tension as well as compression. Finally, field observations from the actual installation operation are compared against the bend test results. Conclusions are presented to address various aspects of concrete coated pipe for S-Lay installations.
A Numerical Investigation of Low Salinity Polymer Flooding Effects from a Geochemical Perspective
Authors: Chaabi Omar , Al-Shalabi Emad W. , Alameri Waleed
Published: August 2021

Low salinity polymer (LSP) flooding is getting more attention due to its potential of enhancing both displacement and sweep efficiencies. Modeling LSP flooding is challenging due to the complicated physical processes and the sensitivity of polymers to brine salinity. In this study, a coupled numerical model has been implemented to allow investigating the polymer-brine-rock geochemical interactions associated with LSP flooding along with the flow dynamics. MRST was coupled with the geochemical software IPhreeqc. The effects of polymer were captured by considering Todd-Longstaff mixing model, inaccessible pore volume, permeability reduction, polymer adsorption as well as salinity and shear rate effects on polymer viscosity. Regarding geochemistry, the presence of polymer in the aqueous phase was considered by adding a new solution specie and related chemical reactions to PHREEQC database files. Thus, allowing for modeling the geochemical interactions related to the presence of polymer.

Coupling the two simulators was successfully performed, verified, and validated through several case studies. The coupled MRST-IPhreeqc simulator allows for modeling a wide variety of geochemical reactions including aqueous, mineral precipitation/dissolution, and ion exchange reactions. Capturing these reactions allows for real time tracking of the aqueous phase salinity and its effect on polymer rheological properties. The coupled simulator was verified against PHREEQC for a realistic reactive transport scenario. Furthermore, the coupled simulator was validated through history matching a single-phase LSP coreflood from the literature. This paper provides an insight into the geochemical interactions between partially hydrolyzed polyacrylamide (HPAM) and aqueous solution chemistry (salinity and hardness), and their related effect on polymer viscosity. This work is also considered as a base for future two-phase polymer solution and oil interactions, and their related effect on oil recovery.
First Time Utilization of Cloud-Based Technology to Fast Track A 521 Million Cell Gas Condensate Reservoir Dynamic Model: A Case Study from Saudi Arabia
Authors: Al-Fawwaz Abdullah A , Al-Dhafiri Yousif M. , Akhtar Muhammad N , Ali Samad , Ibrahim Muhammad , Giddins Marie Ann , Amer Aimen
Published: August 2021

The main objective of this study is to run a high-resolution dynamic simulation on a 521-million cell gas condensate field model for 50 years and capture the effects of gas condensate dropout. Two challenges were encountered on the user and service provider levels. The former is performing such work in a remote location with limited processing hardware resources. The latter is related to resolving memory, CPU allocation, technical support, system resources availability, integration between providers, and simulation needs on user demand.

The approach adopted in this field development planning study was to utilize the latest cloud technology to run the 521 million cell simulation on cloud clusters as well as two upscaled versions (5 and 21 million cells). Such procedures can save significant processing time and money. As opposed to direct purchase and installation of clusters that require maintenance, updates, and become outdated over time, with a cloud cluster that is kept updated and maintained by service providers, significant cost overheads (in millions) could be saved. Using such technology allows operators to get global technical support making executing such simulations viable even in the most remote locations.

The field under study is a gas condensate field that on its own can present multiple challenges including the gas condensate banking impact and compositional modeling. The main strategy adopted in this study was to utilize the static model with no upscaling, to capture the geological details. With the utilization of cloud technology, all simulations were completed in record time. The 5 million cell model was executed in 23 min, while the 21 million cell model executed in 4 hours, and the 521 million executed in 65 hours. The results of the simulations showed that the gas condensate banking effect was captured clearly after the implementation of local grid refinement (LGR) on the upscaled models. A good match was observed in the production profiles for all key parameters, such as gas rates, oil and condensate rates and their cumulative productions.

Using cloud technology saved the operating company over 5 million dollars in cluster hardware direct purchase, support and maintenance costs, making the utilization of the cloud computing technology not only economical, but also bringing about operational efficiencies.

This is the first time a cloud-based dynamic simulation is performed on a 521 million cell model in the world and the first time, an on-demand reservoir simulation based on cloud computing technology has been conducted in the Middle East region. This paper will also show that, given the right model parameters, carefully built smaller models can yield results similar to larger models, highlighting the importance of efficiency.
Online Modeling of CO2 Storage Systems
Authors: Erickson Dale Douglas , Metcalf Greg
Published: August 2021

This paper discusses the development and deployment of a specialized online and offline integrated model to simulate the CO2 (Carbon Dioxide) Injection process. There is a very high level of CO2 in an LNG development and the CO2 must be removed in order to prepare the gas to be processed into LNG. To mitigate the global warming effects of this CO2, a large portion of the CO2 Rich Stream (98% purity) is injected back into a depleted oil field. To reduce costs, carbon steel flowlines are used but this introduces a risk of internal corrosion. The presence of free water increases the internal corrosion risk, and for this reason, a predictive model discussed in this paper is designed to help operations prevent free water dropout in the network in real time.

A flow management tool (FMT) is used to monitor the current state of the system and helps look at the impact of future events (startup, shutdowns etc.). The tool models the flow of the CO2 rich stream from the outlet of the compressor trains, through the network pipeline and manifolds and then into the injection wells. System behavior during steady state and transient operation is captured and analyzed to check water content and the balance of trace chemicals along with temperature and pressure throughout the network helping operators estimate corrosion rates and monitor the overall integrity of the system.

The system has been running online for 24/7 for 2 years. The model has been able to match events like startup/shutdown, cooldowns and blowdowns. During these events the prediction of temperature/pressure at several locations in the field matches measured data. The model is then able to forecasts events into the future to help operations plan how they will operate the field.

The tool uses a specialized thermodynamic model to predict the dropout of water in the near critical region of CO2 mixtures which includes various impurities. The model is designed to model startup and shutdown as the CO2 mixture moves across the phase boundary from liquid to gas or gas to liquid during these operations.
Accelerated Development of Subsurface Safety Valve Technologies
Authors: Edwards Jason Wade
Published: August 2021

Described is a methodology for accelerating the development of innovative and high-risk technologies, specifically, subsurface safety valve technologies. Focus is on methods of mitigating technical and commercial risks that can delay or prevent successful development of new technologies. Example risk assessment and risk mitigation strategies are provided from a recent subsurface safety valve technology development project. Mitigation strategies include fixture level testing, design changes, and deep client collaboration. In the example project, it is estimated that the total development time was reduced by as much as 50% by implementing these strategies. While a subsurface safety valve development is used in this example, it is believed that many strategies are applicable to other domains.
Cyberdefence of Offshore Deepwater Drilling Rigs
Authors: Rossi Paola , Sela Itai , Rizika Adam , Angelidis Diogenes , Duck Mark , Morrison Ron
Published: August 2021

An alternative methodology using new preventative technology to manage cybersecurity exposure on deepwater drilling rig assets is presented. For the past two years Shell's Deepwater Wells business has been evaluating typical cyber defence approaches and undertaken cybersecurity risk assessments and penetration tests. These activities have demonstrated the challenges attaining cybersecure drilling rig environments. Whilst cyberattacks increase in frequency, adaptability, and become cheaper to launch, regulatory and liability insurance requirements are also evolving. To achieve the goal of cyber-resilience, a major Operator has collaborated with a cybersecurity firm to trial technology for rapidly and reliably protecting deepwater rigs.

The paper presents aspects of the numerous challenges faced and offers a different approach using new technology applied to both supplement and accelerate the attainment of a cyber-resilient environment onboard deepwater drilling rigs. It shares the deep dive lessons learnt leading to a more comprehensive understanding of how to protect drilling rigs and their safety critical control systems. Aside from addressing technical attributes using risk vs. maturity based methods, the approach also caters to business demands of short term rig contracts, managing multi-vendor legacy systems and satisfying increasing digitalisation/remote access needs with associated reductions in overall cybersecurity CAPEX spend.
Taylor Bubbles of Viscous Slug Flow in Inclined Pipes
Authors: Dafyak Longtong Abednego , Hewakandamby Buddhika , Fayyaz Ahad , Hann David
Published: August 2021

Unique structures are formed when gases and liquids flow simultaneously in pipelines. The geometric characteristics of these structures are fundamental parameters in intermittent flow regimes. The length of liquid slugs and Taylor bubbles are inputs to mechanistic and empirical models for pressure drop estimation, slug catcher sizing and determination of the periods of no or low liquid in pipelines. Although slug flow has been studied for decades, there still exists a lack of comprehensive understanding of flow structures dynamics due to the complex interactions between the gas and liquid phases in two-phase flow. This study investigates the influence of pipe inclination on the length and hydrodynamics of large gas structures in intermittent flows, particularly, ‘Taylor bubbles’ in slug flow regime. An experimental study was conducted in a 67 mm ID pipe to estimate the bubble lengths of an air-silicone oil mixture from void fraction measurement using a twin-plane Electrical Capacitance Tomography (ECT) tool. The results show that the pipe inclination, gas and liquid flow rates have a substantial effect on the length of large bubbles in slug flow. Taylor bubbles get longer when the void fraction increases, or the pipe inclination deviates towards the horizontal pipe orientation. The influence of pipe inclination on bubble length is quite significant; this variation in bubble length with pipe inclination is attributed to the expansion or compression of large gas structures when there is an alteration on the forces acting on the bubble nose. The weight of the liquid column above the bubble nose which has been often neglected in earlier models was identified to have a notable effect on the volume occupied by the large bubbles and consequently, its length. A semi-mechanistic model is proposed based on the analysis of forces acting on the Taylor bubble nose in a quiescence liquid phase. A comparative analysis of the model and previous models shows that the proposed model outperforms existing mechanistic and empirical models across all pipe inclinations. This study gives an insight into the effect of pipe inclination on the length of large bubbles during slugging in pipes, as these bubbles can be up to 10 times longer in horizontal pipes compared to vertical pipes at the same flow conditions. The proposed model has the potential of estimating the length of large bubbles across all pipe inclinations in upward slug flow with acceptable accuracy, particularly for pipelines installed in undulating terrains.
Wandoo B: Application of Advance Reinforced Concrete Assessment for Life Extension for Non-Jacket Structures
Authors: Sheppard Robert , O’Brien Colin , Moslehy Yashar , Roberts Rachel
Published: August 2021

Wandoo B is a concrete Gravity Base Structure (GBS) and is the main production facility for the Wandoo field offshore NW Australia. It was installed in 1997 with a design life of 20 years. The structural assessments discussed in this paper are part of a comprehensive life extension project encompassing wells, subsea systems, marine and safety systems, topsides facilities and structures to demonstrate fitness for service through the end of field life (EOFL).

The challenge was to demonstrate compliance efficiently and effectively for a large structure with a range of materials (steel, reinforced concrete (RC)) and operations supported (oil storage, drilling, production) under increased loading criteria compared to the original design. There is comprehensive industry guidance for assessing existing steel jacket structures, but far less for a concrete GBS such as Wandoo B. Demonstrating compliance required a combination of computer model results, project-specific tools to check reinforced concrete sections, and engineering judgement to define how much damage constitutes failure.

A number of global and local structural models were developed to assess the linear and nonlinear performance of the reinforced concrete and steel structure. A phased approach was employed using basic, conservative approaches in initial phases to demonstrate code compliance, and progressing to more advanced, less conservative approaches for those components under higher stress.

Developing models that more accurately simulate the behavior of the different structural components and materials was a large part of the project scope, particularly for the nonlinear behavior of the reinforced concrete and the interface connections between the steel and reinforced concrete structures. It was inefficient to develop a detailed steel and reinforced concrete solid model of the large GBS shafts and base, so an equivalent shell model was developed and tested to determine the global behavior and onset of damage. This equivalent model aimed to predict behavior accurately for metocean and seismic loads under material tension and compression. Local detailed models were then developed including a constitutive model of reinforced concrete and used to define the extent of the damage and predict where failure would occur.
Recent Developments in The Use of Hip for The Offshore Industry
Authors: Shipley James , Beamer Chad , Gårdstam Johannes
Published: August 2021

The use of additive manufacturing (AM) technology is growing rapidly for offshore use, whilst established production technologies such as powder metallurgy near-net-shape (PM-NNS) continue to be used. New standards are being introduced and many of the oil and gas majors are now developing supply chains to ensure rapid supply of high-quality complex parts. Environmental concerns are helping to drive this with use of near-net-shape technologies to reduce carbon dioxide emissions through more efficient designs and metal forming methods.

Hot isostatic pressing (HIP) has been used to remove shrinkage porosity and internal defects in cast products for many years, predominantly to improve mechanical properties and fatigue resistance. Recently, there has been an increasing focus on AM processes for demanding applications where localized corrosion and similar internal defects and porosity are a concern. HIP technology is being used to either produce PM-NNS parts, or for the post processing of AM produced components to ensure defect free material prior to service in demanding environments. This paper will present a broad overview in the use of HIP equipment to produce parts and components to the offshore industry.
Fatigue Monitoring and Life Extension for Top Tensioned Production Riser Systems
Authors: Mercan Bulent , Campbell Mike , Thompson Clay
Published: August 2021

Top tensioned production riser (TTR) systems are exposed to fatigue loading in deep water as a result of vessel motions and high currents. The accuracy of predictions of the in-place fatigue response, which is a key input for any life extension requests, is dependent on the operating condition during the life of field including fluid contents and top tension. One solution to reduce this uncertainty is to deploy a fatigue monitoring system to assure the long-term integrity and performance of these riser systems. This paper presents results from a recent TTR monitoring campaign and focuses on the impact of top tension variation on riser motion and fatigue response in the field.

Standalone and ROV deployable motion loggers offer a low cost and robust method of fatigue monitoring. The motion loggers are installed at discrete locations along the TTR to measure riser motions and then determine fatigue accumulations. During one of the recent monitoring campaigns, riser top tension was changed due to operational requirements, which in turn affected the riser fatigue response in the field.

Field data is collected from two periods for two TTRs. The top tension was adjusted between each campaign allowing the effect of tension on riser fatigue response to be better understood using field measurements. The resulting riser motions and fatigue accumulations will be presented to demonstrate the sensitivity to top tension and highlight the importance of maintaining good records during the field life.

Currently, there is no single guideline in the US that addresses TTR life-extension programs in detail. The results from this monitoring program are one step forward in better understanding system behavior of deep water TTRs and assessing the feasibility of an extended service life.
Cost-Effectively Modernizing Offshore Drilling Line-Ups with DC Power Grids and Energy Storage
Authors: Steenberg Thomas , Settemsdal Stig , Valen Alf Olav
Published: August 2021

This paper outlines an approach/solution which enables offshore operators to economically upgrade (i.e., modernize) drilling drive lineups with direct current (DC) based power grids and energy storage.

Many legacy drilling rigs in operation (and ones that are currently stacked/idled) utilize drilling drive technology that is currently obsolete or will be in the near future. Modernizing these rigs can often be an arduous and expensive undertaking. Most drilling setups feature lineups of individual variable frequency drives (VFDs) equipped with dedicated rectifiers, which control power output to motor/consumers, such as mud pumps, the top drive, draw works, rotary table, etc. These alternating current (AC) based setups have been used with success for decades. However, as fuel consumption and emissions, as well as space and weight, have become priorities, DC grid systems have gained interest.

The solution described in this paper is designed to enable drilling rig operators to upgrade to a modern DC power distribution system using the same footprint as the existing drilling line-up and with minimal modifications to cabling. Energy storage, such as batteries or supercapacitors, can also be integrated within the footprint to enhance the performance of drilling operations – for example through peak shaving and blackout prevention.

The solution/approach is highly flexible/modular and is derived from proven concept that has been deployed on hundreds of marine vessels worldwide. The paper provides a description of a solution that is being implemented on a jack-up rig in the Middle East. The new integrated drilling drive setup uses the same footprint, cable network, and communication principles as the rig's existing system and will be comparatively less costly and complicated to implement than simply swapping out existing drives (i.e., one for one replacement).