bluuebunny/crossref_metadata_2025 huggingface dataset:
Failures and Replacements – A Barrier to Growth in Offshore Wind?
Authors: Muren Jan , Jenkins Peter Erik , Froyd Lars
Published: April 2023

Everyone is used to seeing graphs predicting unprecedented growth for the offshore wind industry over the next decades. Whether or not these ambitious goals are achieved remains to be seen, as it will require nothing less than an industrial revolution in offshore construction and installation. Never have such growth projections been backed by a global sense of urgency, but unfortunately, it is not just the growth challenge that has to be met and resolved.

Data from insurance companies show a significant growth in financial losses in the offshore wind industry. For an expanding industry, an increase in insurance claims may be a result of the growth, however, even when normalizing the financial losses against industry CAPEX, number of turbines, or installed capacity, worrying trends are seen. For offshore wind to be a viable energy source in the future, the quality of design, installation and operation needs to improve significantly. Furthermore, the industry cannot continue to scale developments until it has overcome some serious reliability issues.

In offshore wind, we have seen how an extreme focus on reducing CAPEX in projects has led to low-quality engineering and choice of sub-standard products that are not fit for long-term applications exposed to dynamic loading in marine environments. Standardization is needed, reflecting the best insight, experiences, methods, and tools.

Although the challenges were never as extensive in oil and gas as in offshore wind today, the situation still resembles the quality and technology challenges faced by the offshore oil and gas industry some two decades ago. Many of the design challenges that have been overcome in oil and gas have been incorporated into codes, standards, and well-established engineering practices. Seen from a distance, the offshore wind industry experience similar trends. However, with the ongoing rapid growth, the learning and improvement processes need to be accelerated by leveraging the experiences from oil and gas. On the shoulders of a mature offshore industry and today's digital capabilities, standardization and up-scaling of offshore wind have better opportunities than oil & gas had 25 years ago. However, to leverage this opportunity a true life-of-field approach is required.
Utilizing Well Digital Twins to Optimize Offshore Nitrogen Lift Operations
Authors: Alhumaid Saleh , Al-Kadem Mohammad , Daanyal Muhammad , Bayounis Ryyan
Published: April 2023

Nitrogen lifting through coil tubing is widely accepted as an efficient and reliable method for reviving a dead well. In offshore fields, it becomes more challenging to conduct a nitrogen lifting by coil tubing operation given the additional cost of securing a barge, cost of rigless well interventions, logistics and continuously changing weather conditions—all of which create a very limited window of opportunity to conduct a successful nitrogen lifting operation. This paper proposes an advanced method of conducting nitrogen lifting using coil tubing, optimizing for injection rate and depth of injection. The objective of this optimization is to reduce both operation time and consumed volume of nitrogen.

By leveraging emerging technologies, an advanced production modeling algorithm using well digital twins was created to maximize lifting of liquid for each unit of gas injected. The method identified several parameters which can be used for nitrogen lifting by coil tubing—such as injection rate, depth of injection, and injection methodology. Ultimately, given the high levels of computing power needed to conduct this analysis, this method is optimal in offshore rigless activities where there is a limited window of opportunity to conduct rigless operations including nitrogen lifting by using coil tubing. Well digital twin was used to model well and fluid behavior under coil tubing conditions—ultimately calculating Gaslift Utilization Factor (GUF), which is a measure of how much liquid can be lifted for each unit of gas injected. Then, in an iterative process, all the possible parameters that can be changed would be altered to reach the highest GUF factor.

As a pilot to see the outcomes of the advanced modeling algorithm, this method was deployed at an offshore well to revive a well back into normal production. The results were remarkable. There was a 40% reduction in the consumed nitrogen relative to traditional methods, and the job was completed 12 hours ahead of schedule. The tool provides two scenarios, one for most optimal scenario and another option in case the first scenario does not lift the expected volumes of fluid as anticipated. In the trial test, there was no need to resort to the second scenario.

There are plenty of publications related to offshore rigless activities or the use of advanced modeling techniques. None, however, bridge the gap between the two areas combining advanced modeling with rigless operations to increase the efficiency and optimize to reduce cost and time.
Proactive Intervention: A Holistic Examination of Safeguarding Well Integrity, and Optimizing Future Production, to Collaboratively Maximize a Field's Potential
Authors: Billingham Matthew , Cornelio Janio , Singh Kamaljeet , Pacheco Leonardo , Moreira Marcio
Published: April 2023

The paper focuses on the field life cycle and how new technology (including digital) and proactive, collaborative workflows can significantly optimize a field's production, with a focus on Brazil. Specifically, we discuss how, in the presalt, it is important to monitor casing integrity to identify salt creep and deformation as soon as possible. Proactive early identification of issues can accelerate the plugging and abandonment (P&A) decision at a stage where costs are reduced by avoidance of a more complex P&A caused by deformation of major completion components. Considering the complexity of a deepwater intervention, an innovative approach of through-tubing well surveillance was implemented, based on the third interface echo measurement provided by an advanced ultrasonic tool. The technique was deployed in some wells where the casing stress analysis indicated there was a risk of collapse, providing valuable information about casing and tubing integrity, as well as precise identification of annulus content. The paper intends to present local examples of the logs run, collaboration among technical experts, and the decisions made. The scope extends beyond the initial production period to maximizing production, when it is necessary to consider production issues as well as well integrity issues. The paper proposes that conventional KPIs may not measure the real intervention performance and can indeed detract from an optimal outcome.

Most of the wells assessed were found with their integrity preserved, and therefore the production and/or injection, could continue. Where integrity issues were identified, the data gathered were used to redefine the intervention, allowing a safe temporary well suspension, assertive P&A planning, reducing the uncertainties, and facilitating communication with the regulatory agency. The paper will then discuss, during the barrel chasing phase of the field's life, how a better, collaborative alignment of the interests of all shareholders to the outcome of increased production can be achieved. Case studies reflect application of the technique in Brazil. The study demonstrates how to achieve the optimized field life cycle.

New technology, including advanced digital workflows, has been applied to the challenge of well integrity assessment to examine casing deformation in Brazil. This has proven extremely important in early identification of issues to enable the most cost-effective remediation. New collaborative workflows initiated after well integrity optimization optimize production from existing well infrastructure to extend the field life cycle.
Injection Enhancement in a Deep-Water Gulf of Mexico Multi Zone Completion Enabled by Downhole Multi-Position Flow Valves
Authors: Smith Kevin , Esquitin Yosafat , Cone Ryan , Fürstnow Mette , Hazel Paul , Kumar Satish
Published: April 2023

The Deep-Water (DW) Gulf of Mexico (GOM) fields have a complex mix of multi-layered reservoirs, with thicknesses and rock properties which can widely differ from layer to layer within the same reservoir. Injection of 25,000 bpd of water from a shallower aquifer B4 sand via a dump flood technique, benefited from a variable and controlled zonal distribution of the injection into two separate layers connected to the producer B6 Sands over life of well.

This paper presents the modelling performed to achieve optimal choke selection, specified distributions, job execution and results of utilizing multi-position flow valves as part of the 3 ½" completion with the objective of achieving the optimal injection rates in the upper and lower layers of the BB Sands.

Design parameters considered critical by Talos included a controlled and variable distribution of the injection via dump flood of 50%/50% or 25%/75% respectively for the upper and lower layer of the producer B6 Sands, with the option to selective shut-off one of the layers over time, while maintaining the 3 ½" full-bore inner diameter for future interventions.

Discussed within this paper :

The selection process to meet the required distribution rates with the extensive modelling performed using modeling software for the choke size selection, quantity, and distribution in each of the three open positions of the multi-position flow valve to achieve the total flow area required to distribute the injection at the desired rate in each layer of the producer sand, and CFD (Computational Fluid Dynamics) for the choke design. Field data from the first installment of two multi-position flow valves in a well located in the Tornado project, operational considerations that enabled the manipulation of the flow valves and a summary of the achieved results will be presented and explained.

This is the first deployment for the multi-position flow valve with variable chokes in the deep-water Gulf of Mexico well environment. The solution provided controlled injection with variable rates into the two upper and lower producer sands, this technique enables a cost-effective and reliable proven solution which can be applicable to any type of injector well, with the goal to increase the overall NPV of the field, through the increased recoverable using a predictable and safer method of downhole flow control.
Reduced Carbon Dioxide Mobility in Experimental Core Flood Using Surface Coated Silica Nanoparticles as a Foaming Agent
Authors: Alfakher Ahmad M. , DiCarlo David A.
Published: April 2023

Carbon dioxide (CO2) is the most used solvent in enhanced oil recovery (EOR), as it can have a high displacement efficiency in favorable conditions. Its disadvantages are relatively low sweep efficiencies caused by a viscosity and density that is lower than the fluid it displaces. Surface-coated silica nanoparticles create in-situ CO2 foam, which has a more favorable mobility ratio and therefore better sweep. These nanoparticles can also be used in carbon capture and storage (CCS) applications in injecting CO2 foam into brine aquifers.

This paper presents the results of core flood experiments that aimed to study surface coated silica nanoparticles as an in-situ CO2 foaming agent. In these experiments, pressure drop was measured across the core as a whole and in five individual sections. The core was placed vertically, and liquid CO2 was pumped at the top of the core. Surface coated silica nanoparticles suspended in the brine is used in some of the floods and compared to a control flood that had no nanoparticles.

In these experiments, pressure drops in nanoparticle cases were a multiple of 5-10 those in the control cases. In addition, total core pressure drops in nanoparticle cases increased as the core got more saturated with CO2, and the increase was observed sequentially in each section as it got invaded by CO2.The mobility of CO2 was reduced by an order of magnitude on average compared to the control. The CO2 moved slower through the core and breakthrough was delayed in the nanoparticle case.

The study provides quantitative nanoparticle CO2foam mobility measurements and calculations, compared to those in control cases. Properties calculated from this study can be used to improve both EOR and CCS applications of CO2 flooding by scaling the results to the reservoir scale.
SIIBED: Investigation of Ice Loads on Subsea Pipelines and Cables Using RHITA
Authors: Thijssen Jan , Fuglem Mark , Taylor Rocky , Afzali Soroosh
Published: April 2023

Medium scale indentation tests have been conducted using a 12.75" diameter rigid pipe indenter, mounted on a purposely designed test frame (RHITA – Rapid High-capacity Impact Test Apparatus) and large laboratory made freshwater ice samples (approximately 4 m3 each). The purpose of this study is to collect ice failure data, representative of iceberg keel interactions with subsea pipelines or electrical cables laying on the seabed. Previous assessments of pipe response due to iceberg impact conservatively assumed no ice failure. As no widely accepted numerical models is available that captures prevalent ice failure mechanisms, experimental data was collected using RHITA. The data can be implemented in a coupled ice-pipe-soil FEA as a pressure or force limit to the ice. Also, the data can serve for calibration and validation of numerical models of ice fracture or ice crushing.

The tests were executed at 0.2 m/s, a typical iceberg drift speed, on the Grand Banks of Newfoundland and Labrador. An ice mould was used to grow ice samples measuring 2.5x1.5x1.0 m (LxWxH). The top half of the ice sample was exposed, the bottom half confined by the mould. Global loads during the 2.0 m interaction were measured using six load cells, and tactile pressure sensors were used to measure the ice pressure distribution on the indenter. The test matrix includes variations of interaction depth, ice geometry, embedded rock material and ice temperature.

The observed ice failure mechanisms ranged from localized damage near the interaction zone, to large fractures spanning the entire sample. The tactile pressure sensors showed the interface pressure distribution across the contact area, largely affected by local spalling events. Ice temperature and associated boundary conditions were found to affect the propagation of the cracks and resulting loads.

This paper presents a summary of the tests executed from June 2022 to January 2023. Future works will include testing of rigid and flexible flowlines, and subsea electrical cable samples.
New Measurements Provide Enhanced Understanding of New York Bight Wind Resource
Authors: Eichelberger Scott , Brennan Katie
Published: April 2023

Understanding the wind resource potential across the New York Bight (NYB) offshore region is critically important for the winners of the Bureau of Ocean Energy Management's (BOEM's) February 2022 offshore wind energy auction. Early-stage feasibility studies and bidding strategies for the NYB offshore wind leases relied on Numerical Weather Prediction (NWP) model simulations in combination with floating LiDAR buoy data deployed by the New York State Energy Research & Development Authority (NYSERDA). While the NYSERDA buoys are hugely valuable, additional measurements in the region will be needed to further refine wind energy analyses and reduce uncertainty as the wind leases are developed and eventually financed. In this work, we will explain where TGS is deploying additional floating LiDAR buoys and show early results comparing the TGS and NYSERDA buoy data.
1D Hydro-Geomechanical Modelling of Pore Pressure on an Active Convergent Margin: East Coast Basin, New Zealand
Authors: Calderon Medina Erika E. , Obradors-Prats Joshua , Aplin Andrew C. , Jones Stuart J. , Rouainia Mohamed , Crook Anthony J.
Published: April 2023

This study aims to understand the causes of anomalous pore fluid pressures within sedimentary sequences of an active tectonic basin through well log analysis, pressure data evaluation and thermo-hydro-geomechanical modelling. The study focuses on the East Coast Basin (ECB), New Zealand, an active convergent margin, where anomalously high pore pressures have been encountered in deep-water systems at burial depths as shallow as 200 m.

A regional investigation including analysis of the Cretaceous to Holocene tectono-stratigraphy and diagenetic histories of the ECB, was combined with seismic and well log interpretation to understand the structural and sedimentation history of the ECB, and thus the main factors that were likely to contribute to overpressure generation/dissipation and porosity loss. 1D hydro-geomechanical models were then built to undertake a parametric study to investigate the effect on porosity and pore pressure evolution of different sedimentation and erosion rates, hiatus periods, different erosion thicknesses, and tectonic compression. The parametric models show that high overpressures can be preserved during rapid erosion events due to the relatively small timeframe for pore pressure dissipation, depending on sediment permeability. Furthermore, only recent erosion events are relevant to the present-day overpressure. In addition, high levels of tectonic compression (12.5 %) applied in recent events can produce both high pore pressure values and significant porosity reduction if the sedimentary column was undercompacted prior to the tectonic compression.

Learnings from the parametric studies were used as a starting point to understand controls on the pore pressure and porosity in the Opoutama-1 well, located on the onshore area of the ECB. Results from the Opoutama-1 well show that the high pore pressure registered at shallow depths (< 1 km) in this well is significantly driven by tectonic compression as a result of high subduction rates (presently 48 mm/yr). Disequilibrium compaction also contributed to overpressure generation due to high sedimentation rates (up to ~3000 m/Ma). However, much of the disequilibrium compaction-related overpressure was dissipated during uplift, hiatus, and erosion. Where overpressure is preserved, it is related to thick (up to 1 km) mudstone packages deposited during the Cretaceous to Holocene, thin low permeable layers of limestones deposited during the Miocene to Pliocene and marl intervals with high content of smectite.
Geopressured Geothermal – Correlations to Offshore High Pressure High Temperature Geothermal Opportunities
Authors: Batir Joseph F. , Gentry Emilie N. , Soroush Hamed
Published: April 2023

The northern Gulf of Mexico basin contains geopressured zones ideal for geothermal energy production, still to be explored. These systems are defined by primarily Eocene to Miocene sands that are confined by shale beds, which facilitates the formation of anomalously high pressures and temperatures. The overpressure in these zones results in an increased geothermal gradient, which makes geopressured zones of interest for geothermal exploration. Resources are commonly found at 3 to 6 km depth and reservoir fluid temperatures can range from 90 to 200°C. There has been a substantial amount of work done to understand these geopressured reservoirs on the Gulf Coast for geothermal potential. Many of these geopressured zones extend and exist offshore in the Gulf of Mexico. The knowledge and technical success of wells completed in these geopressured zones onshore can be transferred to understand how to produce a high pressure high temperature offshore well for geothermal power production. This paper will provide a review of previous work on geopressured geothermal zones in the Gulf Coast, the challenges with these systems, how these were overcome, and the knowledge transfer of those findings for offshore geothermal opportunities in high pressure high temperature wells.
Technology Advancement in Deepwater Pipeline Repair to Mitigate Offshore Risk and Application Case Study of Duplex Pipe Recommissioning by ROV Operation
Authors: Hao Ziyong , Kaundal Pardeep Kumar , Liu TaoHsin , Mckinlay Samuel Ramos , Ouyang Simon , Tang Fei , Shavandi Mohsen , Cheng Chen
Published: April 2023

Deepwater pipeline repair planning and execution plays an important role to ensure the pipeline integrity during its service life. Due to the complexity of the work and capital associated, a more rigorous design and testing qualification program on the repair connector is needed to account for the offshore campaign risk. This paper details a complete qualification program which is compliant to the latest industry recommend practice and how the design/qualification approach can be used to scale into a different size with less testing involved after proper risk assessment. A case study describes the installation application of a scaled design in this method to recommission the Pipeline End Termination (PLET).

This paper will discuss, for the first time, the qualification program in detail to mitigate the deepwater pipeline repair or tie-in risk following the latest industry recommended practice. The paper will also present application of this technology to re-commission the subsea production system with tie-in 2 in. flexible hose by ROV.
Experience of Low Salinity Water Flooding in Mumbai High Field - First Offshore Field in India to Implement Enhanced Oil Recovery Technique
Authors: Dwivedi Siddhant , Awasthi Dheeraj K , Pandey Saurabh , Prasad Sheel Ranjan , Ram Binay , Zahir Mohammed , Bose Subhojit , Mathavan C
Published: April 2023

Low Salinity water flooding (LSWF) is a potential method for enhanced oil recovery (EOR). Lab and simulation studies of U-III reservoir in Mumbai High field indicates that the reduction of injection water salinity results in significant increase in oil recovery. On the basis of these studies, LSWF has been started in large pilot area in carbonate X1 layer of U-III reservoir in Mumbai offshore.

In Mumbai High Field, U-III reservoir has been under conventional sea water flooding for pressure maintenance and better volumetric sweep which has yielded nearly 30% recovery over the past 4 decades.

In search of feasible EOR process for further increase in recovery, numerous studies have been taken up in the past but high temperature, high salinity and pressure were major challenges in application of conventional EOR towards field implementation in Mumbai High. In addition, offshore conditions and multilayered reservoir with vertical and horizontal heterogeneity makes implementation of any EOR process even more challenging. After screening many EOR processes, low salinity water flooding was found to be most feasible solution which is environment friendly, cost effective and comparatively easy to implement in offshore conditions considering vast network of injection infrastructure (pipelines, facilities) already existing in Mumbai High.

Over the past two decades there has been significant growth in evidence supporting the use of low salinity water flooding as a viable EOR method. LSWF unlocks oil by improving microscopic and macroscopic displacement efficiency. It involves physical (such as fines production that can block high permeable zones thereby increasing sweep efficiency) and/or geochemical process involving complex Crude Oil-Brine-Rock (COBR) interactions. Decrease in residual oil saturation is due to resultant change in rock wettability (more water wet) thereby enhanced oil recovery. In cases worldwide, LSWF can improve the oil recovery by almost 5 to 10% as per core displacement studies and few field pilot tests.

This paper discusses the entire workflow adopted starting from EOR screening, Core studies, identification of Pilot area, Simulation studies and subsequent field implementation as a multiwell pilot. Further, the surveillance mechanism has also been discussed in this paper. The results of this pilot project will be a torch bearer for ONGC to implement LSWF in entire Mumbai High field in future.
Gimbal Joint Riser: Qualification Program of a Novel Concept
Authors: Amorim Andre Ramiro , Ribeiro Felipe Oliveira , Gomes Rodrigo Klim , Carvalhal Rodrigo do Nascimento , Diezel Alexandre Rezende
Published: April 2023

As oil and gas exploration is moving to deeper waters, a key challenge is to design risers in harsh environments. Steel catenary risers (SCR) are cost-effective solutions that have been used in offshore developments due to their simplicity and robustness. However, stresses at the touchdown zone (TDZ), in such configurations are very large in ultra-deep waters for FPSOs in harsh environments leading the solution to become unfeasible in some fields. Therefore, steel lazy-wave risers (SLWR), are the market solutions for those fields. Nonetheless, SLWRs are, normally, longer risers with buoyancy modules, which increases installation time and overall cost.

Gimbal Joint Riser (GJR) provides an alternative to reduce stresses at TDZ in SCRs. It is a patented device that comprises a series of hinged connection elements placed around a flexible pipe. This mechanism articulates, absorbing the energy coming from the motion of the hang-off, thus reducing stresses at TDZ.

GJR is currently under qualification process. Recently, an experimental campaign involving two small scale models have been concluded. This paper brings a summary of the improvement in the GJR development obtained from these tests. A numerical model has been built to represent the experiments and the results of the calibrated real scale model derived from the experimental outputs are also presented. Results show a significant mitigation in the compressive wave at the TDZ of between 50% to 70% reduction in energy in comparison to SCRs.
Asphaltene Deposition Simulator with Aggregation
Authors: Mateen Khalid , Smith Eric William
Published: April 2023

Asphaltene stability, aggregation, and transport are coupled with hydraulic and heat transfer equations to predict the effects of asphaltene deposition in wellbores and pipelines. The model uses lab measurements to characterize the asphaltene in solution and develop a precipitation curve in a pre-processing step. Smoluchowski coagulation theory predicts the rate of aggregation of smaller particles into larger particles in a geometric distribution. Finally, the resulting concentration of asphaltene particles diffuses to the wall as determined by mass convection theory. An innovative approach (Saidoun 2000), where only the primary particles, and not the aggregates, contribute to the deposit is also formulated. This second model has been successfully used to match 9 years of production data and screen a greenfield system for asphaltene risks. The simulator is deployed as a standalone desktop application built on React.JS and electron communicating to a Wolfram Engine kernel over gRPC.
Case Study: Use of Digital Twins to Mitigate Risks in Pull-Out Operations of Damaged Risers
Authors: Lobo Daniel De Moraes , Dos Santos Lucas André , Araújo Pereira Leury , Axelsson Gunnar , Duncan Marotta Rodrigues Felipe
Published: April 2023

A digital twin is proposed to quantify the loads and mitigate the risk of rupture during the recovery operation of a flexible riser with severe structural weakness (30% of broken wires in the outer tensile armor layer). The allowable axial tension is compared with the loads expected during operation to establish safe operating limits. The digital twin is divided into a local model and a global model. The local analysis uses a finite element model to investigate how stresses on tensile armor wires change when the number of broken wires increases. It considers all pipe layers and two configurations, 1) straight and 2) with a curvature expected during the recovery operation. The FPSO motion performance is calibrated by offshore field measurements and improved RAOs for the global analysis are provided based on the measured motions. Finally, the allowable axial load from the local analysis is compared with the expected loads from the global analysis. The local model is simulated stepwise with 0 - 28 broken wires and indicated a reduction of 83% in allowable axial load with 25 broken wires. The results were combined with global simulations considering different sea states to provide insights about how close the loads might be to the allowable limit during operation and what loads the riser was subjected to since the last broken wires were detected. This analysis allowed the identification of the most critical steps in operation and helped to design the procedure to achieve ALARP risks. Finally, operating limits were discussed to keep the estimated load inside the established limits.
Injector Well Performance Optimization
Authors: Izgec Bulent , Prasad R.S. , Ross Jim
Published: April 2023

This paper presents an integrated multi-disciplinary approach to optimize the value of water, that is, barrels of water injected per barrel of oil produced. Value of water (VoW) is optimized through focusing on the following critical components of a successful injector: Optimum drilling and completion programAbility to inject above fracture pressureInjection system availability with high water qualitySurveillance and analysis-driven ramp-ups to target injection rates

Drilling program optimization includes well trajectory alignment with maximum horizontal stress, selection of acid-soluble stress cage materials when used, and considerations involving proper perforating gun selection. Completion design optimization includes vertical and/or near vertical entry to the formation, an efficient completion type selection based on the rock strength/competency, proper breakdown of the formation along with a pre-injection acid treatment.

The topsides facility requirements for injecting above fracture pressure is ensured with full field thermal geomechanical simulations coupled with injection network models to capture the changes in fracturing conditions with depletion and cooling. These simulations also incorporate injectivity decline models required to account for injection water quality variations over time. Topside's injection water specifications are maintained through filtration and chemical treatments with daily measurements of sulphate, oxygen, chlorine levels for souring and scaling prevention.

Surveillance and analysis-driven ramps to target injection rates are achieved by integrating multiple methods for efficient diagnostics along with signposts; advanced Hall plots for real-time continuous monitoring, numeric/analytic pressure transient analysis for reservoir characterization, skin tracking, material balance methods for investigating aquifer support, and history-matched integrated thermal/geomechanical simulation models to gain insights into dynamic fracture behavior for improved sweep.

Case studies from several deep offshore injectors show how the integrated multi-disciplinary approach was successfully used to drill, complete, and operate injectors. Initial negative skins point to the successful optimization of drilling and completion programs. Sustained injectivities for more than 5 years demonstrate the benefits of surveillance and analysis-driven, consistent, and repeatable ramps with rest periods during unplanned shutdowns. Field data along with numeric/analytic reservoir studies suggest good support of producers and low VoW numbers.

This work combines the best practices for a successful injector in the areas of reservoir engineering, geomechanics, drilling, completions, production, and operations. Also, an extensive holistic injector well performance analysis approach is outlined integrating thermal/geomechanical/ geochemical simulations, numeric/analytic pressure transient analysis (PTA), advanced Hall plots and injection network/wellbore models.
The Future of Underwater Asset Surveys | Completely Remote Visualizations in 2D and 3D
Authors: Kooh Riley
Published: April 2023

The adoption of imaging technologies to create 2D and 3D models is becoming more and more common in the management of critical infrastructure. In most cases of submerged infrastructure, remotely operated vehicles (ROVs) are the only way to easily capture reliable data for modeling. Underwater asset surveys previous to ROVs relied on commercial dive teams using handheld equipment. This methodology is primarily limited to commercial diving safety regulations related to maximum depths, working in confined entry, and time limitations from oxygen levels. Alternatively, autonomous unmanned vehicles (AUVs), unmanned surface vessels (USVs), or a standard ships equipped with imaging technologies could be utilized, however, details are limited at depths or confined spaces.

The use of different imaging sensors on ROVs such as stereo cameras, sonars, and laser scanners allow operators to capture data to build detailed structural models in both 2D or 3D with unparalleled accuracy. Recent field results have confirmed the validity of the application of these technologies for real-world use. The variety offered by the three different practices, and modular simplicity of integration allows for these modeling techniques to be be widely interchangeable between use-cases.

Using a mounted dual-frequency imaging sonar, ROV operators were recently able to complete an entire 2D model of a submerged tunnel measuring 60 metres in length, with widths raging from 0.7 - 1.0 metres. A battery powered ROV was remotely deployed from a small topside vessel, and performed multiple runs of the submerged tunnel within a three day period to examine this otherwise impossible enter tunnel for a pre-construction assessment. Similarly, an offshore survey company based in Newfoundland was able to generate a 2D model of a Floating Production, Offloading, and Storage (FPSO) Vessel’s prop using an ROV-mounted laser scanner to verify the necessary blade clearances within millimetres.

The most detailed model was generated in 2022 by a southern Ontario archaeology team within a civil engineering company. The crew used two different ROVs to repeatedly capture high resolution photos every two seconds as they ran multiple passes over a historical dam structure. After running their collected images through the modeling program Agisoft Metashape, the crew successfully generated an extremely accurate 3D model of the submerged structure from just one day’s worth of imagery.
Changing the Game - Enhanced OTEC System Design
Authors: Robinson Roy , Engelmann Georg
Published: April 2023

Ocean Thermal Energy Conversion, better known as OTEC is a base load power source that runs on the temperature difference between warm surface water and cold depths. Generally, the accepted minimum temperature difference is 18°C, with a minimum surface water temperature of 25°C. The maximum possible thermal efficiency of these systems is 3% to 7% and requires massive flows of seawater. The concept was first developed in the 1890's but has struggled since then, with every commercial scale system to date suffering failures on the cold water riser due to required pipe diameter (up to 14m being considered) and the required water depth to reach the cold waters, usually taken as greater than 1000 meters.

This paper presents the thermodynamic analysis of an Enhanced OTEC system that will allow for an order of magnitude reduction in the size of the down risers. This enhancement should both improve the performance of the OTEC system and reduce the cost, bringing the Levelized Cost of Energy on par with Offshore Wind.

Using computer modeling the new system is compared to a conventional system's performance. A comparison using a thermodynamics and energy balance, outputs of the models are used to confirm that the increase in power and a reduction required riser size are possible. The new system provides significant improvements in terms of performance, while adding some mechanical complexity, in the form of a second closed fluid loop. The Enhanced OTEC system (E-OTEC) will bring this century old technology into the 21st century as a leading source of clean energy. It is unlike any existing OTEC system.
Vito Project: Host Construction and Commissioning
Authors: Dixon Paul Christopher , Wild Brady , Hernaiz Maria , Rush Keith Richard , Smith Greg Neil
Published: April 2023

In 2009, the Vito field was discovered in more than 1,200 m of water approximately 240 km offshore from New Orleans, Louisiana in the Gulf of Mexico (GoM). The project produces from reservoirs nearly 9,100 m below sea level. This paper provides the efficiencies in constructing the Vito FPS at a single fabrication yard, commissioning, and preparation for offshore installation. This paper is part of a Vito Project series at OTC 2023 and the other papers are listed in the references.

The Vito Floating Production System (FPS) has a Lightship of 21,500 mt, Topside Lift Weight of 8,700 mt, and is 86 m Length × 86 m Width overall. Vito FPS fabrication at a single fabrication site included Hull Fabrication, Topside Fabrication, Living Quarters (LQ) Fabrication, Integration, and a majority of the Commissioning Scope. Key drivers to be successful at a single site included demonstratable safe execution, offshore fabrication quality capability, fabrication yard throughput availability, achievable integration execution plan, and competitive pricing. Following a transport to a readiness site adjacent to the Gulf of Mexico, four months of continued commissioning and preparation for offshore installation included the key activities of installation of the Temporary Living Quarters, riser and umbilical installation winches, tow-out and station-keeping rigging; de-preservation, final commissioning and verification of operability of key systems; aviation readiness and safety equipment verification; and final USCG inspections to obtain the Authorization to Proceed Offshore.

The efficiencies identified and realized at the single fabrication site during the Vito FPS fabrication execution included focused safety at a single site, simplified quality weld procedures, single interface for detail engineering, simplified procurement delivery plan for Company Provided Items (CPI), efficient preservation strategy, single regulatory interface site, enhanced site team efficiencies in engineering and inspection, and simplified contracting at a single source. The readiness site integrated members of the Construction, Commissioning and Operation teams utilizing a single location to quickly mobilize various vendor teams for a final preparation for offshore installation without the constraints of remote offshore work.

A key enabler to select the fabricator was their ability to complete a majority of the commissioning scope on the ground prior to integration of the complete Topside and Hull based on the single lift capability of the new 2 × 15,000 mt gantry cranes, which further increased the efficiency at the single fabrication site. 85% of the commissioning was completed by a Commissioning Management Contractor (CMC) prior to integration including load testing and dynamic commissioning of all the major rotating equipment.
Update on the Challenges to Offshore Facility Decommissioning on the California Coast
Authors: Smith John Bridge , Byrd Robert Clark
Published: April 2023

The authors have been working with the challenges related to decommissioning facilities offshore California since 1996. In a 2018 OTC paper (OTC-28844-MS) they reviewed the challenges for offshore facility decommissioning in this region. This paper reviews the oil and gas platform decommissioning projects being conducted on the federal Outer Continental Shelf (OCS) offshore California and the decommissioning outlook for OCS platforms through the end of this decade. There are a total of 23 oil and gas platforms on the federal OCS offshore California which are submerged lands located more than three nautical miles from the coastline. The authors project that one-third of the 23 OCS platforms and one state water platform are likely to be decommissioned by the end of the decade, and at least 50 percent of the OCS platforms are likely to be removed by the middle of the next decade. Three of the eight OCS platforms being decommissioned, if fully removed, would each establish world water depth records for removing conventional steel platform jackets from the seafloor. The paper also describes the major technical, logistical, environmental, and regulatory challenges operators face in planning and conducting decommissioning projects offshore California.
Industry Application and Benefits of ISO/TR 12489 for Reliability Modelling and Calculation of Safety Systems
Authors: Estecahandy Maïder , Selvik Jon T. , Signoret Jean-Pierre , Summers Angela , Isaksen Stefan L. , Brissaud Florent , Clave Nicolas
Published: April 2023

The paper presents benefits of applying the ISO technical report ISO/TR 12489, i.e., a document providing guidance for analysts on how to perform reliability modelling and calculation of safety systems. The objective of the paper is to show how this document adds value when used in relevant industries, including oil, gas, and lower carbon energy industries.

The benefits are discussed and illustrated using examples of safety systems in gas production, processing, and signal transmission applications. These discussions and examples reflect the broad guidance given in the ISO/TR 12489, covering different approaches and technical challenges within this area with explanations regarding how to solve these. An aim of the ISO technical report is to close a gap between the state-of-the-art and the application of probabilistic calculations for safety systems, where the paper contributes to this aim by illustrating how the ISO technical report applies in practice with focus on the methods and tools covered.

Several application areas and benefits are addressed, such as: relevant issues encountered when implementing relevant standards, and particularly the IEC 61508 and IEC 61511; the understanding of key concepts and approaches; the use of simplified approaches; understanding of systemic approaches and demonstration that they can be simpler to implement than so-called ‘simplified formulae’; how to use common standardized models for more complex situations (e.g., reliability block diagrams, fault trees, Markovian approach and Petri nets); and how to assess the frequency of failures. The observations show that the ISO technical report plays a key role in supporting the existing framework in how to perform probabilistic modelling and calculations in a safety context.

Safety systems are necessary to protect industrial installations against undesired events. The illustrations given in this paper show how the ISO/TR 12489 can guide assessments leading to acceptable safety levels for protected installations and safer oil and gas industries including lower carbon energy.
Compressor Optimization for Capacity and Efficiency Improvements in a Mature Facility
Authors: Sleight Neil Colin , Nguyen John , Seppala Christopher
Published: April 2023

The authors will present examples of how revising base layer control strategies have resulted in improved compressor operation in a mature deep-water asset. The revised control strategies have resulted in improved production and capacity whilst reducing greenhouse gas production.

Existing control schemes were in place for multiple compressors at the asset; Vapor Recovery (VRU), Gas Lift (GLC) and Field Gas Compression (FGC). In the case of the VRU, process dynamics exceeded the ability of the control scheme to provide good control and a new valve position control scheme was designed and implemented. Further gains were realized through automated surveillance techniques which identified controller induced disturbances which when removed increased useable capacity by 16%. For the Gas Lift compressor, the initial control scheme would not work under low gas lift demand conditions. The control scheme was dealing with upstream disturbances, resulting in frequent trips and higher than expected energy consumption. Finally the FGC control scheme was adjusted to allow recycle to be minimized at all times without compromising process control.

Through the use of new control strategies existing compressors are being operated in new and more efficient ways. This has led to direct results to the business in terms of additional oil and gas production whilst also reducing energy intensity in line with the business strategy. Furthermore, the changes have resulted in reduced recycling meaning the compressors are capable of greater useable throughput. The wear to control valves has also been reduced.

The field examples presented show how advanced surveillance tools and strategy adjustments can lead to meaningful and cost-effective improvements even for control schemes that were initially meeting expectations. With the focus on energy efficiency being renewed by the oil and gas industry the examples given may extend to other production facilities.
A Review of Laser Peening Method to Mitigate Stress Corrosion Cracking in Stainless Steels for Subsea Distribution Systems
Authors: Kumar Anil
Published: April 2023

Stress corrosion cracking (SCC) is a phenomenon caused by the combined effects of a corrosive environment and sustained tensile stress. SCC is an integrity concern for high value assets in energy sector such as wellheads, offshore production platforms, processing plants, power plants and pipelines.

Because stainless steel is often selected for design in subsea distribution systems, this makes SCC a great concern to the industry.

This paper will explore and propose new ideas to mitigate SCC in subsea distribution systems, such as Laser Shock Peening (LSP). The paper reviews the existing literature on the effects on SCC from variety of laser parameters such as laser intensity, wavelength, frequency, pulse duration etc. The study involves an overview of the resulting effect of residual compressive stresses on material behavior at different depths.

The conclusion of the study explores and proposes surface modification techniques using lasers to mitigate the SCC in subsea distribution systems. The paper intends to provide clarity on laser shocks to create compressive stress at different depths to make the stainless-steel material more sustainable.