Offshore Oil Industry Research Articles

Effects of the COVID-19 pandemic on employees' psychological health in the offshore oil and gas industry and opportunities for improvement

Effects of the COVID-19 pandemic on employees' psychological health in the offshore oil and gas industry and opportunities for improvement

Intraspecific Variation in the Sublethal Effects of Physically and Chemically Dispersed Crude Oil on Early Life Stages of Atlantic Cod (Gadus morhua).

The offshore oil industry in Atlantic Canada necessitates a greater understanding of the potential impacts of oil exposure and spill response measures on cold-water marine species. We used a standardized scoring index to characterize sublethal developmental impacts of physically and chemically dispersed crude oil in early life stages of Atlantic cod (Gadus morhua) and assessed intraspecific variation in the response among cod families. Cod (origin: Scotian Shelf, Canada) were laboratory-crossed to produce embryos from five specific families, which were subsequently exposed prehatch to gradient dilutions of a water-accommodated fraction (WAF) and a chemically enhanced WAF (CEWAF; prepared with Corexit 9500A) for 24 h. Postexposure, live embryos were transferred into filtered seawater and monitored to hatch; then, all live fish had sublethal endpoints assessed using the blue-sac disease (BSD) severity index. In both WAF and CEWAF groups, increasing exposure concentrations (measured as total petroleum hydrocarbons) resulted in an increased incidence of BSD symptoms (impaired swimming ability, increased degree of spinal curvature, yolk-sac edemas) in cod across all families. This positive concentration-dependent increase in BSD was similar between physically (WAF) versus chemically (CEWAF) dispersed oil exposures, indicating that dispersant addition does not exacerbate the effect of crude oil on BSD incidence in cod. Sensitivity varied between families, with some families having less BSD than others with increasing exposure concentrations. To our knowledge, our study is the first to demonstrate the occurrence in fishes of intraspecific variation among families in sublethal responses to oil and dispersant exposure. Our results suggest that sublethal effects of crude oil exposure will not be uniformly observed across cod populations and that sensitivity depends on genetic background. Environ Toxicol Chem 2022;41:1967-1976. © 2022 SETAC.

Modeling the Evolution of Major Storm-Disaster-Induced Accidents in the Offshore Oil and Gas Industry.

Storm disasters are the most common cause of accidents in offshore oil and gas industries. To prevent accidents resulting from storms, it is vital to analyze accident propagation and to learn about accident mechanism from previous accidents. In this paper, a novel risk analysis framework is proposed for systematically identifying and analyzing the evolution of accident causes. First, accident causal factors are identified and coded based on grounded theory (GT). Then, decision making trial and evaluation laboratory (DEMATEL) is integrated with interpretative structural modeling (ISM) to establish accident evolution hierarchy. Finally, complex networks (CN) are developed to analyze the evolution process of accidents. Compared to reported works, the contribution is threefold: (1) the demand for expert knowledge and personnel subjective influence are reduced through the data induction of accident cases; (2) the method of establishing influence matrix and interaction matrix is improved according to the accident frequency analysis; (3) a hybrid algorithm that can calculate multiple shortest paths of accident evolution under the same node pair is proposed. This method provides a new idea for step-by-step assessment of the accident evolution process, which weakens the subjectivity of traditional methods and achieves quantitative assessment of the importance of accident evolution nodes. The proposed method is demonstrated and validated by a case study of major offshore oil and gas industry accidents caused by storm disasters. Results show that there are five key nodes and five critical paths in the process of accident evolution. Through targeted prevention and control of these nodes and paths, the average shortest path length of the accident evolution network is increased by 35.19%, and the maximum global efficiency decreases by 20.12%. This indicates that the proposed method has broad applicability and can effectively reduce operational risk, so that it can guide actual offshore oil and gas operations during storm disasters.

The compensation system for marine ecological damage resulting from offshore drilling in China

In the past four decades that China has devoted to its offshore oil exploration and production, a model of joint development between the China National Offshore Oil Corporation (CNOOC) and foreign operators has been used. Drilling for oil offshore is a challenging task with multiple hazards, as oil spills both from daily operations and from offshore accidents, endangers the marine ecosystem of nearby waters. Unlike traditional damage (i.e., personal injury and property damage) via the environment, tort liabilities resulting from marine ecological damage require a separate regime where relevant rules are scattered in different legal instruments. Some unique features rooted in the Chinese offshore oil industry fundamentally shape the liability distribution and the approaches to ecological remediation. The Bohai Bay Oil Spill in 2011 demonstrated that China was in urgent need of dealing with this issue in practice. This study will describe the applicable legal remedies concerning this type of damage and analyse the existing compensation system. Based on a law and economics approach, some observations are made on the efficiency of the regime to evaluate if the applicable rules are in line with economic starting points when compensating marine ecological damage arising from offshore drilling.

Concurrent 23. Presentation for: National Decommissioning Research Initiative outcomes inform offshore decommissioning options

Presented on Thursday 19 May: Session 23 The Australian offshore oil and gas industry is facing a significant decommissioning portfolio over the next few decades. In response to this, in 2019, eight Australian oil and gas operators and the National Energy Resources Australia (NERA) established the National Decommissioning Research Initiative (NDRI) with the aim to fill key knowledge gaps on the potential environmental impacts, risks and benefits of different decommissioning options in Australia’s offshore environment. In Phase 1, seven research projects were undertaken covering the interaction that occurs between the environment and oil and gas infrastructure in Australia’s oceans. These projects focused on habitat, connectivity, invasive marine species, degradation of metals and non-metals and potential contaminants of concern such as mercury and naturally occurring radioactive materials. Two other projects were undertaken to gain insights into regulators, stakeholders, marine users and scientist views on offshore decommissioning risks and opportunities. This paper describes the drivers for NDRI, the outcomes of the Phase 1 projects and the future projects to be undertaken to support the environmental assessment of different decommissioning options. To access the presentation click the link on the right. To read the full paper click here

EKF-Based Vision-Assisted Target Tracking and Approaching for Autonomous UAV in Offshore Mooring Tasks

In the offshore oil and gas industry, the most productive fields are located in increasingly distant waters, so the oil pipelines as a solution to transport the production become less attractive to build and operate. Therefore, the offshore loading operations with shuttle tanker (ST) vessels take the lead in transporting oil production. These operations occur throughout the facilities’ lifespan and represent a risky and complex task, mainly in the approach, mooring, and connection stages between the oil rig and the ST vessel. This work’s goal is to present the improvements and experimental results of a previous theoretical framework which focuses on enhancing the safety and performance of this task by using aerial robots to transfer the messenger cable between the platform and the ST on mooring and connection operations for offloading. This framework consists of a hybrid navigation methodology based on computer vision artificial intelligence for object tracking, with a sensor fusion technique using extended Kalman Filter (EKF) for autonomous unmanned aerial vehicles (UAVs) to safely navigate to and approach the destination, and therefore it could be used to assist critical stages of the offloading operation, improving safety. The proposed framework was developed in the robot operating system (ROS) and tested on a physical UAV using in scale ship models to validate the theoretical results (obtained in previous simulations). It was also subjected to a field test as proof of concept. The results demonstrated both the robustness and viability of the proposed methodology and also the cost reduction potential for real-life operations.

Environmental risk assessment of inter-well partitioning tracer compounds shortlisted for the offshore oil and gas industry

Quantifying residual oil saturation (SOR) in the inter-well region of oil and gas reservoirs is key for successfully implementing EOR solutions. Partitioning inter-well tracer tests (PITTs) has become a common method for quantifying SOR. A new group of seven chemicals – pyridine, 2,3-dimethyl pyrazine, 2,6-dimethyl pyrazine, 4-methoxybenzyl alcohol, 3,4-dimethoxybenzyl alcohol, 4-chlorobenzyl alcohol, and 2,6-dichlorobenzyl alcohol – have been proposed as potential partitioning tracers for quantifying SOR. Using these tracers can lead to their environmental release in the marine environment through produced water discharges, with currently limited knowledge on impacts in the marine ecosystem. The primary objective of the present study is to assess the environmental risk of discharging the tracer compounds in the marine environment. We investigated the fate and effect of these tracers in the marine environment. Biodegradability in seawater was measured to understand the fate of tracers in the marine environment. The acute toxicity of tracers was measured in terms of the percent cell viability of a rainbow trout gill cell line (RTgill-W1) and growth inhibition of the algae Skeletonema costatum. The ecotoxicological information obtained from these experiments was used in the dynamic risk and effects assessment model (DREAM) to calculate the tracers’ contribution to the environmental impact factor (EIF). The results from the DREAM simulations suggest no contribution towards EIF values from any of the tracers at the expected back-produced concentrations. Results from simulations at higher concentrations suggest that both pyrazines have the lowest environmental risk, followed by 3,4-dimethoxybenzyl alcohol, 4-methoxybenzyl alcohol, and pyridine; while both chlorobenzyl alcohols show the highest environmental risk.

SARS-CoV-2 genomic surveillance as an evidence-based infection control approach in an offshore petroleum employee population

BackgroundIndustrial hygienists (IH) in the oil and gas business instituted an extraordinary number of safety protocols to limit spread of SARS-CoV-2 onto offshore platforms in the Gulf of Mexico. We used genomic surveillance to provide actionable information concerning the efficacy of their efforts.MethodsOver 6 months, employees at a single company were serology and PCR tested during a 1-5 day predeployment quarantine and when postdeployment symptoms were reported. From each positive test (n = 49), SARS-CoV-2 genomes were sequenced. Phylogenetic analysis was used to investigate the epidemiology of transmissions.ResultsGenomic surveillance confirmed 2 viral strains were infecting 18 offshore workers. Genomic data combined with epidemiological data suggested that a change in quarantine protocols contributed to these outbreaks. A pre-deployment outbreak involved a WHO variant of interest (Theta) that had infected 4 international workers. Two additional predeployment clusters of infections were identified.ConclusionsOur findings support that IH quarantine/testing protocols limited viral transmissions, halted offshore outbreaks, and stopped the spread of a variant of interest. The study demonstrates how genomic data can be used to understand viral transmission dynamics in employee populations and evaluate safety protocols in the offshore oil and gas industry.

National Decommissioning Research Initiative outcomes inform offshore decommissioning options

The Australian offshore oil and gas industry is facing a significant decommissioning portfolio over the next few decades. In response to this, in 2019, eight Australian oil and gas operators and the National Energy Resources Australia (NERA) established the National Decommissioning Research Initiative (NDRI) with the aim to fill key knowledge gaps on the potential environmental impacts, risks and benefits of different decommissioning options in Australia’s offshore environment. In Phase 1, seven research projects were undertaken covering the interaction that occurs between the environment and oil and gas infrastructure in Australia’s oceans. These projects focused on habitat, connectivity, invasive marine species, degradation of metals and non-metals and potential contaminants of concern such as mercury and naturally occurring radioactive materials. Two other projects were undertaken to gain insights into regulators, stakeholders, marine users and scientist views on offshore decommissioning risks and opportunities. This paper describes the drivers for NDRI, the outcomes of the Phase 1 projects and the future projects to be undertaken to support the environmental assessment of different decommissioning options.

Risk transfer assessment model of integrated energy system in the process of offshore oil and gas production

The offshore integrated energy system plays important role in the offshore oil and gas processing industry. To ensure the safe development of offshore oil and gas resources, accurately assessing their risks is crucial. First, this article describes the risk factors that affect the operation of the equipment and builds a risk model that takes into account the relevance of the coupled system; then, a risk transfer model based on material–energy analysis is proposed, which describes the transfer of risk through material–energy flow. In addition, according to the structure and operating characteristics of the offshore integrated energy system, a risk indicator system has been designed from five levels: operational risk, energy supply risk, structural risk, economic risk and environmental risk. Finally, by taking the simulation experiment of an offshore oil and gas platform, the proposed model in this paper evaluates the risks of offshore oil and gas platforms accurately.

Calculation of volume fractions regardless scale deposition in the oil industry pipelines using feed-forward multilayer perceptron artificial neural network and MCNP6 code

During the production of oil and gas, barium sulfate (BaSO4) scale occurs on the inner walls of the tubes leading the reduction of the internal diameter, making the fluid passage difficult and complicating the calculation of volume fractions of fluids. In this sense, this study presents a methodology for the development of volume fractions of fluids multiphase meters and the prediction of barium sulfate (BaSO4) scale thickness. The spectra obtained by two NaI(Tl) detectors that record the transmitted and scattered beams are used as input data for the artificial neural network without the need of any parametrization method. Theoretical models for annular flow regime were developed using MCNP6 code. Different volume fractions and scale thickness values of oil-water-gas were generated as a data set to train and evaluate the neural network. The results indicate that it is possible to calculate the volume fraction regardless the scale thickness in offshore oil industry pipes. More than 88% of the results showed errors below 5% for all investigated samples.

Coating Failure Prevention for Industrial Valves by Substrate Surface Preparation in Offshore Oil and Gas Industry: A Literature Review

Coating Failure Prevention for Industrial Valves by Substrate Surface Preparation in Offshore Oil and Gas Industry: A Literature Review

Safety and reliability analysis for butterfly valves in the offshore oil and gas industry

Valve systems are essential components in piping systems in a variety of industries, including oil and gas to stop and start the flow of fluid, regulate and control fluids, prevent backflows, and provide safety. The safety and reliability of industrial valves is an increasingly critical issue that has been addressed in previous studies. In case of valve failure due to mechanical failure, material corrosion, poor manufacturing and testing, there can be negative consequences including loss of assets, leakage into the environment, and other issues. The objective of this study is to develop a method for measuring the safety and reliability of safety critical butterfly valves by combining safety integrity level (SIL) and failure mode and effect analysis (FMEA). On the basis of operational data, butterfly valve failure rates are estimated. Safe failure fraction (SFF) are calculated at approximately 89% for the valves and converted into SIL2 that meets the end-user requirements.

Progress and prospect of CNOOC's oil and gas well drilling and completion technologies

Offshore oil and gas production has become an important growth pole to ensure national energy security. However, China's offshore oil and gas production is lack of key core technologies and weak in tool and equipment foundation and can hardly support the optimized fast development of important fields. To solve these technological difficulties, China National Offshore Oil Corporation (CNOOC) insisted on independent technological innovation and overcame a series of key core technologies through theoretical research and key technology research and test during the 13th Five-Year Plan. And the following research results are obtained. First, several key technologies are broken through, including efficient drilling and completion in the middle and deep layers of the Bohai Sea, offshore large-scale heavy oil thermal recovery, deep-water oil and gas field development, and high temperature and high pressure well drilling and completion in the South China Sea, unconventional oil and gas stimulation, and offshore emergency rescue. Domestic first independently operated ultra deep water giant gas field, namely “Deepsea 1” is successfully put into production, so that the leap from 300 m to 1500 m of water depth and from exploration to development is realized. Second, key tools and equipment are developed, such as logging while drilling and rotary steering drilling system, deep-water drilling surface conductor, underwater emergency killing device, and underwater wellhead Christmas tree, which promote the high-quality development of China's offshore oil industry. Finally, some suggestions are proposed as follows. In the future, CNOOC shall strengthen independent technological innovation, quicken the pace to deepsea oil and gas, and continue to research key core technologies for oil and gas reserves and production increase (e.g. continuous localization of drilling and completion technologies, equipment and materials in complex fields), commingled gas production and test and green energy transformation (e.g. geothermal energy), so as to make greater contributions to ensure national energy security and build a maritime power.

Numerical investigation and structural optimization of bonded joints with fiber reinforce plastic sucker rods in offshore reservoirs

ABSTRACT Sucker rod constructed of FRP (fiber-reinforced plastic) is currently used in offshore oil and gas industries due to its high tensile strength, lightweight, and resistance to corrosion. Due to the fact that the surface of FRP sucker rod cannot be threaded, it is often attached to steel joints via adhesive technology, and the bonded joint of FRP sucker rod is particularly prone to breaking and coming off. The current research is primarily concerned with the mechanical properties of FRP sucker rods, with little emphasis on the adhesive performance of bonded connections. This research developed a numerical model with a novel bonded joint structure based on the cohesion failure criteria. An indoor test was used to determine and confirm the expected bonded joint failure load. Additionally, an orthogonal test was conducted to maximize the adhesion performance. The findings indicated that a) theaccuracy of numerical model was within 2% and b) when the groove angle was 30°, the length ratio was 2/23, each groove was 14 mm in length based on a triangular groove, and the anticipated failure stress of the bonded joint was around 443 kN, an increase of 10%.

Effects of temperature, concentration and synergism on green Schiff bases synthesized from vanillin in applications as corrosion inhibitors for carbon steel in well stimulation

Mild carbon steel is widely used in construction materials owing to its relatively low price, ease of manufacture and high tensile strength. When it is subjected to an aggressive environment, the use of efficient corrosion inhibitors is required. The offshore oil and gas industry apply well stimulation techniques employing strong acids (5–35 wt%), which severely damage metallic structures. Conventional inhibitors may result in environmental and human health problems. In order to avoid that, green compounds have been widely investigated. However in certain applications, such as materials for offshore installations, protection is afforded by multi-component formulations. The synergistic effect of formulations is achieved by the active compounds, intensifiers, surfactants and solvents. Thus the performance of three Schiff bases synthesized from vanillin, a green aldehyde, and aromatic amines was investigated in corrosion inhibition of carbon steel. Weight loss measurements were made in 2 M and 15% HCl over a 313K–353K temperature range in concentrations between 0.4%wt./v and 1.0%wt./v. Effects of binary and ternary mixtures in 15% HCl revealed an increased efficiency for isolated inhibitors at higher concentrations. The addition of potassium iodide enhanced efficiency to 97.78% in 15% HCl at 333 K. Electrochemical tests indicated mixed-type inhibitors. Surface analysis confirmed the presence of a protective film as well as reduced carbon steel roughness. Density-functional theory (DFT) calculations revealed the effects of a substituent on structural and electronic properties in the neutral and acid phases. The role of a sulfur atom in preventing corrosion was also addressed by DFT calculations.

A time-dependent vessel routing problem with speed optimization

We study an operational planning problem arising in the offshore oil and gas industry, in which we determine routes, as well as sailing speeds along these routes, for a set of platform supply vessels (PSVs) servicing a given set of delivery and pickup orders such that costs are minimized. The sailing costs, mainly induced by fuel consumption for the PSVs, heavily depend on the chosen sailing speeds. Furthermore, the fuel consumption and the feasible speed ranges for the PSVs are largely affected by weather conditions that may vary over time, resulting in a weather- or Time-Dependent Vessel Routing Problem with Speed Optimization (TDVRP-SO). Optional decisions include the postponement of certain orders and the chartering of spot vessels, both associated with additional costs. We present a time-discrete mixed integer programming (MIP) model for the TDVRP-SO. To overcome the challenges of solving large-scale instances of the TDVRP-SO with a commercial MIP solver, we propose an Adaptive Large Neighborhood Search (ALNS) heuristic extended with a local search and a set partitioning model. The ALNS heuristic also includes solving the sub-problem of determining the optimal sailing speeds along each PSV route. Computational tests on instances based on a real planning case from the Norwegian continental shelf show that the ALNS heuristic efficiently provides high-quality solutions. It is also demonstrated that, in contrast to current planning practice, accounting for speed optimization and weather conditions significantly improves the solutions.

Mitigation of Flow-Induced Vibration of Steel Catenary Risers with Pounding Tuned Mass Damper

Steel catenary risers (SCR) have been widely used in the offshore oil industry. This paper proposes using a novel vibration control device, i.e., the pounding tuned mass damper (PTMD), to mitigate the flow-induced vibration of an SCR. The numerical model of the SCR and the PTMD has been established in ANSYS. The soil-pipe interaction is simulated by nonlinear springs based on p-y curves. A single degree of freedom structure is utilized to verify the PTMD model established in ANSYS using APDL. Afterwards, numerical studies are carried out to validate the vibration control performance of the proposed PTMD and to investigate the influence of mass ratio and the location of the PTMD. The numerical results imply that the PTMD is very effective in reducing the displacement of the SCR under different oceanic conditions. The vibration control effectiveness will increase with the increase in mass ratio. The maximum vibration reduction is achieved when the PTMD is located at the place where the largest amount of motion takes place.

Numerical study on the displacement reconstruction of subsea pipelines using the improved inverse finite element method

The structural health monitoring (SHM) and integrity management of subsea pipelines are essential in the offshore oil and gas industry. Previous studies have achieved strain and thermal monitoring using distributed fiber optic sensors (DFOS). However, assessing the in situ displacement of subsea pipelines is still challenging. This study put forward a displacement reconstruction approach based on limited strain data using the inverse finite element method (iFEM). First, we developed a new inverse beam element with a 2nd order shape function for axial deformation to extend the application scope of the standard iFEM to subsea pipelines undergoing complex axial forces. Then, a model truncation procedure and a continuous displacement reconstruction algorithm were proposed to rebuild high accuracy and smooth displacement field. Besides, the strain sensing scheme for iFEM was adapted to DFOS system and made easier to implement in engineering applications. Finally, the proposed method was verified through a series of numerical studies. It showed that the improved iFEM offers superior accuracy and better noise robustness than the standard iFEM, especially with coarse meshes and low spatial resolution strain data. Thus, it reveals a promising prospect in the online displacement monitoring and SHM for subsea pipelines.

Probabilistic bearing capacity of spudcan foundations under combined loading in spatially variable soils

Spudcan foundations are widely used in the offshore gas and oil industry to support mobile jack-up drilling rigs. During the service period, the spudcan foundations need to resist large vertical-horizontal-moment (VHM) loads that are transmitted from the superstructure. The bearing capacity of foundations in complicated stress conditions is usually based on VHM failure envelopes. These are commonly constructed by using numerical methods where the soil properties are assumed to be deterministic, ignoring the inherent spatial variability. This paper investigates the influence of spatially variable undrained shear strength and embedment depth on the capacity of spudcan foundations under VHM combined loads. The linearly increasing undrained shear strength with depth obeying log-normal distribution was taken into account. Probabilistic failure envelops were constructed to analyse the effect of spatial variability on the bearing capacity of spudcan foundations at various embedment depths when subjected to different combinations of VHM loads. The influence of horizontal scale of fluctuation for a specific embedment depth was also investigated. The results indicated that under combined loading the embedment depth significantly influenced the shape and size of failure envelopes. The probability of failure at each embedment depth based on the obtained probabilistic failure envelopes was intuitionally represented by means of a factor of safety, which can provide specific guidance for foundation reliable designs.