Offshore Petroleum Research Articles

A simplified economic model predictive control for a gas lifted oil production network based on modifier adaptation

We propose a novel simplified economic model predictive controller (EMPC) for supervisory control of an offshore petroleum production network composed of two wells, a riser, and a separator. The proposed controller uses a gradient-and-modifier-based methodology to mimic a nonlinear EMPC (it considers a nonlinear process model and cost function), while only solving quadratic programming. We alter the modifier adaptation to depend on an estimator and employ slack variables to improve feasibility. Tips for appropriate design, to improve stability and robustness, are presented. Since the tested facility is subject to multiple disturbances, we also use a regulatory controller to stabilize the system. Finally, we compare our method to a linear EMPC and self-optimizing control in various scenarios considering disturbances, noise, and model inconsistencies. The proposed controller always tends towards the economic optimal point, presenting similar nominal performance as the others advanced controllers and better robustness.

Integrated team approach to decommissioning Environment Plan development

The offshore oil and gas industry is facing a significant transition period in the coming decades due to the evolving energy market and aging oil and gas infrastructure. Industry has over 1000 offshore wells to plug and abandon, 57 fixed facilities and over 8000 km of subsea lines to decommission over the coming decades. Most of this significant portfolio is regulated by NOPSEMA (National Offshore Petroleum Safety and Environmental Management Authority) with the expectation that decommissioning involves the full removal of equipment as per Section 572 of the Offshore Petroleum and Greenhouse Gas Storage Act 2006 (Cth) (OPGGS Act). However, other options may be considered if the titleholder can demonstrate that an alternative decommissioning approach delivers equal or better environmental and safety outcomes compared to complete removal. Integration of environment and engineering functions primarily occurs during the process of developing an Environment Plan (EP) and, specifically, the process of identifying environmental hazards (Environmental Hazards Identification, ENVID) and mitigation measures. This paper proposes that improved stakeholder, regulatory, cost and environmental outcomes could be achieved through an earlier integrated approach to planning decommissioning activities. Specifically, co-designing an approach to decommissioning at the earliest stages would inform, for example, approvals strategy and equipment selection. This would ultimately result in improved outcomes without the application of mitigating control measures. The paper will discuss some of the current challenges and outline the value of early identification and understanding of key environmental values and sensitivities to ensure site-specific information is considered during planning stages, later streamlining EP development. A multi-disciplinary decommissioning team in the early stages of project development enhances problem-solving capabilities and ultimately improves environmental and safety outcomes.

Collaborative Seismic Environment Plan (CSEP) project – a long-term, consistent, consortium-based approach to environmental approvals

The Collaborative Seismic Environment Plan (CSEP) project was formed in 2018 by NERA (National Energy Resources Australia) and an industry consortium of marine seismic acquisition operators and exploration titleholders. Using a collaborative approach, the vision of the CSEP project was to streamline seismic survey environment plan preparation, submission and assessment by the regulator (National Offshore Petroleum Environmental and Safety Authority, NOPSEMA), with an emphasis on mutually agreed protocols with commercial fishers operating within the CSEP Operational Area. Stakeholder consultation undertaken during Environmental Plan (EP) preparation was identified by the consortium as a principal cause for concern and a common reason for unsuccessful EP submissions. The CSEP project has achieved the project’s vision through: A Commercial Fishing Industry Adjustment Protocol to provide a standardised, evidence-based process to assess and provide monetary adjustment to commercial fishers for loss of catch, displacement and gear loss/damage; an Operational Protocol to provide guidance regarding improved communications with commercial fishers, including the spatial and temporal repetition and advanced notifications of seismic activities; a single overarching approvals framework for seismic activities within the CSEP Operational Area; a consistent assessment of environmental receptors, potential impacts, and management controls for seismic activities; and Improved understanding of potential cumulative impacts of seismic activities across the CSEP Operational Area. The CSEP project is an example of best practice stakeholder consultation that can be applied to offshore oil and gas and renewable energy activities.

Impact of offshore petroleum extraction and “ocean grabbing” on small-scale fisheries and coastal livelihoods in Ghana

Impact of offshore petroleum extraction and “ocean grabbing” on small-scale fisheries and coastal livelihoods in Ghana

Impact assessment of high-risk analytes in produced water from oil and gas industry

This study characterizes and evaluates the constituents of produced water at production wells and dumping sites. The study examined the impact of offshore petroleum mining activities on aquatic systems for regulatory compliance and the selection of management and disposal options. The physicochemical analyses of produced water from the three study locations were within the permissible range for pH, temperature, and conductivity. Of the four heavy metals detected, mercury had the lowest concentration at 0.002 mg/L, while arsenic the metalloid, and iron had the highest concentrations at 0.038 mg/L and 36.1 mg/L, respectively. The total alkalinity values for the produced water in this study are about six-fold compared to the other three locations (Cape Three Point, Dixcove, University of Cape Coast). Compared to the other locations, produced water had higher toxicity to Daphnia, with an EC50 value of 80.3 %. The levels of polycyclic aromatic hydrocarbons (PAHs), volatile hydrocarbons, and polychlorinated biphenyls (PCBs) analyzed in this study were all insignificant in terms of toxicity. The total hydrocarbon concentrations indicated a high level of environmental impact. However, considering the possible breakdown of total hydrocarbons over time, and the marine ecosystem's high pH and salinity conditions, further recordings and observations should be conducted to ascertain the overall cumulative effects of oil drilling activities at the Jubilee oil fields along the shores of Ghana.

The subsurface thermal state of Svalbard and implications for geothermal potential

Svalbard is a High Arctic Archipelago at 74–81°N and 15–35 °E under the sovereignty of Norway. All settlements in Svalbard, including the capital of Longyearbyen (population 2400), currently have isolated energy systems with coal or diesel as the main energy source. Geothermal energy is considered as a possible alternative for electricity production, as a heat source in district heating systems or harnessed for heating and cooling using geothermal heat pump installations. In this contribution we present the until now fragmented data sets relevant to characterize and assess the geothermal potential of Svalbard. Data sets include petroleum and deep research boreholes drilled onshore Svalbard, 14 of which have recorded subsurface temperature data at depths below 200 m. Geothermal gradients on Spitsbergen vary from 24 °C/km in the west to 55 °C/km in the south-east, with an average of 33 °C/km. Four deep research boreholes were fully cored and analyzed for thermal conductivity. These analyses were complemented by thermal conductivity calculated from wireline logs in selected boreholes and four measurements on outcrop samples. 1D heat flow modelling on five boreholes calibrated with the measured thermal conductivities offers insights into heat transfer through the heterogeneous sedimentary succession. Offshore petroleum boreholes in the south-western Barents Sea and marine heat flow stations around Svalbard provide a regional framework for discussing spatial variation in heat flow onshore Svalbard, with emphasis on the effects of erosion and deposition on the thermal regime. We conclude that Svalbard's geology is well suited for geothermal exploration and potential production, though challenges related to permafrost, the presence of natural gas, heterogeneous reservoir quality and strongly lateral varying heat flow need to be adequately addressed prior to geothermal energy production. Specifically for Longyearbyen, high geothermal gradients of 40–43 °C/km in the nearest borehole (DH4) suggest promising sub-surface thermal conditions for further exploration of deep geothermal potential near the settlement.

An interpretable and augmented machine-learning approach for causation analysis of major accident risk indicators in the offshore petroleum industry

The offshore petroleum industry faces continuous stress and threats of major accidents. A complete and well-designed spectrum of indicators could help identify and improve the understanding of the status of all relevant hazards for managing various risks on offshore installations. The Petroleum Safety Authority (PSA) in Norway develops a project of extended indicators, i.e., “Trends in risk level” (RNNP), which uses an assortment of risk indicators to reflect the status and trend of the risk level. However, a simple statistical approach is insufficient to see into the causes behind the risk indicators. This paper proposes an interpretable and augmented machine-learning approach for causation analysis of major accident indicators. The proposed methodology integrates the K-means SMOTE technique for data augmentation to promote the performance of machine-learning algorithms. Armed with the analytical approach, the problem of lack of sample data is solved and the importance of the features of risk indicators is analyzed. Furthermore, a case study is presented to augment and analyze the two types of risk indicators associated with major accidents recorded from 2005 to 2021. The effectiveness of the proposed approach is demonstrated by the case study. It can provide an effective tool to help find out which type of features deserves more attention in risk management and target risk reduction measures that could be taken to strengthen safety on offshore installations.

Advancing the robustness of risk regulation for offshore drilling operations in China

Robust regulation has become a pursuit in risk governance of offshore drilling operations over the recent decade. However, the idea of robust risk regulation has not been fully developed in China. This paper aims to explore what affects the robustness of risk regulation and how can a robust regulatory regime for offshore drilling operations be achieved in China. It begins with an identification of risks and values of the offshore petroleum industry, highlighting that robust regulation is the primary means to manage such risks in offshore drilling operations. It then discusses dimensions of regulatory robustness and assesses and compares regulatory regimes for this high-risk offshore petroleum industry in the United Kingdom, Norway, the United States and China. In specific, the Chinese paths to govern the risks of offshore operations are summarized. A key theoretical debate on regulating offshore drilling operations is which regulatory modes can better facilitate the robustness of risk regulation. The command-and-control regulation and self-regulation represent two primary regulatory modes of offshore risk regulation. The former is strongly dependent upon public enforcement while the latter emphasizes internal continuous improvement of the offshore petroleum industry. To develop robust offshore regulation in China, this paper suggests that a certain combination of the two modes is necessary to deliver optimal regulatory outcomes.

Cyber-physical oil spill monitoring and detection for offshore petroleum risk management service

Petroleum industry has started to embrace the advanced petroleum cyber-physical system (CPS) technologies. Offshore petroleum CPS is particularly hard to build, mainly due to the difficulty in detecting and preventing offshore oil leaking. During the oil exploration and transportation process, the remote multi-sensing technology is typically employed for emerging service. It can be utilized for leak detection by enabling the underwater modeling of an offshore petroleum CPS. However, such a technology suffers from insufficient remote sensing resources and expensive computational overhead. In this work, a cross-entropy based leak detection technique is proposed to detect the oil leak, which facilitates the understanding of the oil leak induced marine pollution. Furthermore, a hierarchical parallel approach is proposed on the super computer Tianhe-2 to improve the efficiency of the proposed leak detection technique. Experimental results on Penglai oil spill events demonstrate that the proposed method can effectively identify the sources of oil spilling with accuracy up to 100%.

Towards enhancing major emergency initial response training: a comparative study of STCW and OPITO standards

The maritime industry has been characterized as a high-risk domain owing to various risks associated with its complicated operations. This aspect imposes significant importance on the human element role, especially during unanticipated events. When major emergencies occur on ships, the response of the ship’s Master and his supporting team becomes crucial in controlling the situation and preventing the escalation of threat. In recognition of this fact, the IMO Standards of Training, Certification and Watchkeeping (STCW) 95/2010 convention has developed a range of emergency response competencies. However, data on accidents and incidents in shipping reveal that the human element is still considered the primary factor contributing to most cases of ship loss. Furthermore, several cases have been reasoned for improper and ineffective management of the emergency. This might raise serious concerns regarding the adequacy of IMO model courses and whether they provide learners with the required level of knowledge, skills, situational awareness, and confidence to appropriately respond should a real major emergency occurs onboard. With the aim of enhancing the current level of maritime emergency management training, the authors of this study intended to identify possible gaps in current STCW training criteria by conducting a comparison with similar emergency response training standards established by the Offshore Petroleum Industry Training Organization (OPITO). The Qualitative analysis was used to compare three case studies of emergency-related STCW courses with two OPITO courses that have similar objectives, in terms of their aims, scopes, principles, outlines, number of delegates, outcomes, decision-making processes and assessment criteria, in order to assess whether the OPITO emergency response training provides more extensive scope for ensuring the optimum management of an extended range of emergency events rather than the currently delivered STCW courses. The study is concluded by identifying possible gaps and proposing specific modifications to the STCW standard which can be marked as a first step in the direction of establishing effective training for managing and controlling major emergencies onboard ships.

Night shift work and risk of aggressive prostate cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort.

Night shift work may acutely disrupt the circadian rhythm, with possible carcinogenic effects. Prostate cancer has few established risk factors though night shift work, a probable human carcinogen, may increase the risk. We aimed to study the association between night shift work and chlorinated degreasing agents (CDAs) as possible endocrine disrupters in relation to aggressive prostate cancer as verified malignancies. We conducted a case-cohort study on 299 aggressive prostate cancer cases and 2056 randomly drawn non-cases in the Norwegian Offshore Petroleum Workers cohort (1965-98) with linkage to the Cancer Registry of Norway (1953-2019). Work history was recorded as years with day, night, and rollover (rotating) shift work, and CDA exposure was assessed with expert-made job-exposure matrices. Weighted Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for aggressive prostate cancer, adjusted for education and year of first employment, stratified by 10-year birth cohorts, and with 10, 15, and 20 years of exposure lag periods. Compared with day work only, an increased hazard of aggressive prostate cancer (HR = 1.86, 95% CI 1.18-2.91; P-trend = 0.046) was found in workers exposed to ≥19.5 years of rollover shift work. This persisted with longer lag periods (HR = 1.90, 95% CI 0.92-3.95; P-trend = 0.007). The exposure-hazard curve for a non-linear model increased linearly (HRs ≥1.00) for 18-26 years of rollover shift work. No association was found with CDA exposure. Long-term exposure to rollover shift work may increase the hazard of aggressive prostate cancer in offshore petroleum workers.

Investigation of the liquid carryovers in the branching T-junction, based on historical data

High liquid content is obtained in the T-junction side arm, which affects the operational performance of downstream equipment installed in offshore petroleum industries. Diameter ratio, velocity ratio, and side arm angle of T-junction play dynamic role to control phase redistribution. The effect of these parameters on liquid take-offs is unclear from literature, without any agreement among researchers. Literature only provides empirical correlations valid for one specific application for which the correlations were developed. There is a dire need of correlations with high accuracies to conclude the effect of a certain variable on liquid carryovers based on available data. Objectives of this study are to collect data from multiple research publications, develop easy to use correlations, and to study parameters response surfaces. Plot digitization and Design Expert software are utilized for data collection and statistical analysis, respectively. Results depicted that phase separation improves by reducing diameter ratio to 0.33 and upward inclined side arm. Furthermore, liquid carryovers escalate by increasing velocity ratio and decrease at higher velocity ratios. This research study is first attempt in last few decades which is based on collection of data from different experimentation facilities and eliminating confusions among researchers about effect of parameters on phase separation.

Regulator Analyzes Australia’s Decommissioning Challenge

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper SPE 208483, “Is Australia Prepared for the Decommissioning Challenge? A Regulator’s Perspective,” by David Christensen and Andrew Re, National Offshore Petroleum Safety and Environmental Management Authority. The paper has not been peer reviewed. _ The Australian offshore petroleum industry has been in operation since the early 1960s and at the time of writing has approximately 57 platforms, 11 floating facilities, 3500 km of pipelines, and 1,000 wells in operation. Many offshore facilities are now approaching the end of their operational lives. Modeling has estimated Australia’s combined offshore petroleum industry decommissioning liability (including wells, pipelines, subsea equipment, and facilities) to be $40.5 billion. The purpose of the complete paper is to highlight the importance and benefit of adopting best practices when planning for decommissioning throughout the life cycle of a petroleum project. Introduction Australia’s offshore petroleum decommissioning challenge is significant given its remote location, limited availability of specialist services, and the relative infancy of its offshore industry in undertaking large-scale decommissioning projects. Recent events in Australia have shown that the industry is, broadly speaking, unprepared for decommissioning. Australian Regulatory Approach The Offshore Petroleum and Greenhouse Gas Storage (OPGGS) Act of 2006 and associated regulations provide the legal framework for the exploration and recovery of petroleum and greenhouse gas activities in Australian Commonwealth waters (those areas that are more than 3 nautical miles from the territorial sea baseline). The key principle underpinning the OPGGS Act and regulations is that responsibility for ensuring the health and safety of workers and the protection of the environment lies with those who create the risks. An objective-based regulatory regime sets requirements that must be achieved but does not prescribe how those requirements must be met. The National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has been established and appointed under the OPGGS Act as regulator for health and safety, structural (well) integrity, and environmental management of petroleum activities in Australian waters (3–200 nautical miles offshore) and in coastal waters (0–3 nautical miles offshore) where regulatory powers and functions have been conferred. Section 572, Maintenance and Removal of Property. Section 572 of the OPGGS Act establishes requirements for maintenance and removal of property by the titleholders, along with exemptions and obligation provisions. Section 572(2) of the OPGGS Act provides that a titleholder must maintain in good condition and repair all structures that are, and all equipment and other property that is, in the title area and used in connection with operations. Section 572(3) of the OPGGS Act provides that a titleholder must remove from the title area all structures that are, and all equipment and other property that is, neither used nor to be used in connection with the operations in which the titleholder is or will be engaged.

STUDY ON THE SOCIAL RISK OF PETROLEUM EXPLORATION AND DEVELOPMENT ACCIDENTS: A CASE OF MACONDO ACCIDENT IN THE GULF OF MEXICO

The process of petroleum exploration and development is related to many factors. A large number of safety accidents occur every year around the world and have an impact on the society. Due to the particularity of Marine environment, safety accidents in the process of offshore petroleum exploration and development usually have serious impacts. Taking Macondo accident in Gulf of Mexico as an example, this paper studies the social risk of petroleum exploration and development accident. On the basis of introducing the accident background, the accident process and the accident consequence, the technical reason and the management reason of the accident are analyzed, and the social influence of the accident is further analyzed. The root cause of the incident was BP's catch-up schedule, which resulted in a lack of compliance with cementing procedures such as casing running, cement injection, cement waiting, cement bond logging, and negative pressure testing, as well as inadequate supervision. After the accident, the technical treatment effect of petroleum spill was not good, and the government blindly emphasized responsibility and took little initiative to participate in the accident treatment, which turned the social risk into a social crisis and caused terrible effects. The accident seriously affected the lives of coastal residents, caused great harm to Marine life, and damaged the Marine ecological environment of the Gulf of Mexico.

Benzene Exposure From Selected Work Tasks on Offshore Petroleum Installations on the Norwegian Continental Shelf, 2002-2018.

Work on offshore petroleum installations may cause exposure to benzene. Benzene is a carcinogenic agent, and exposure among workers should be as low as reasonably practicable. We aimed to assess short-term (less than 60 min) benzene exposure from the most frequent work tasks on offshore installations on the Norwegian continental shelf and identify determinants of exposure. In addition, we aimed to assess the time trend in task-based benzene measurements from 2002 to 2018. The study included 763 task-based measurements with a sampling duration of less than 60 min, collected on 28 offshore installations from 2002 to 2018. The measurements were categorized into 10 different tasks. Multilevel mixed-effect Tobit regression models were developed for two tasks: sampling and disassembling/assembling equipment. Benzene source, season, indoors or outdoors, design of process area, year of production start, sampling method, and work operation were considered as potential determinants for benzene exposure in the models. The overall geometric mean (GM) benzene exposure was 0.02 ppm (95% confidence intervals 95%(CI: 0.01-0.04). The pipeline inspection gauge (PIG) operation task was associated with the highest exposure, with a GM of 0.33 ppm, followed by work on flotation cells, disassembling/assembling, and sampling, with GMs of 0.16, 0.04, and 0.01 ppm, respectively. Significant determinants for the disassembling/assembling task were work operation (changing or recertifying valves, changing or cleaning filters, and breaking pipes) and benzene source. For sampling, the benzene source was a significant determinant. Overall, the task-based benzene exposure declined annually by 10.2% (CI 95%: -17.4 to -2.4%) from 2002 to 2018. The PIG operation task was associated with the highest exposure out of the ten tasks, followed by work on flotation cells and when performing disassembling/assembling of equipment. The exposure was associated with the type of benzene source that was worked on. Despite the decline in task-based exposure in 2002-2018, technical measures should still be considered in order to reduce the exposure.

Challenges for Norway in implementing intergenerational equity in its offshore petroleum

This article examines the challenges faced by Norway in implementing intergenerational equity in its offshore petroleum licensing regime. Norway has been considered by many to be a leader in the regulation of its offshore petroleum, with an emphasis on state control and encouraging a prudent approach by operators, but also emphasising rational and efficient solutions. Unlike some other countries, it has also enacted legislation to support its convention obligations in relation to matters like pollution and the protection of biodiversity. These obligations are also reflected in its constitution. But climate change and other challenges as it moves exploration into more sensitive northern areas are throwing a spotlight on the conflict between those matters and Norway’s vital oil economy.

Risk Assessment for Off-Shore Petroleum and Gas Construction Projects in Egypt

Risk Assessment for Off-Shore Petroleum and Gas Construction Projects in Egypt

Nigeryjski system zarządzania ryzykiem eksploatacji podmorskich złóż ropy naftowej. Czy ustawa o przemyśle naftowym z 2021 r. wypełnia istniejące luki?

The occurrence of several offshore petroleum accidents in Nigeria supports the conclusion by some authors that the Petroleum Act (PA) 1969 regime is fraught with lapses. Environmental protagonists have applauded the Petroleum Industry Act (PIA) 2021 as the way forward in the regulation of offshore risk. This paper uses the non-doctrinal methodology to investigate the extent to which the PIA 2021 has progressed beyond the PA 1969 in effectively regulating offshore risk in Nigeria’s petroleum sector. Such analyses are predicated on the general principles of effective risk governance regime evidenced in international best practices. This study finds that the PIA 2021 has not successfully filled the existing gaps identified in the PA 1969 regime. It was argued that while the PIA provides for the establishment of a separate regulator, it retains the defects of the 1969 Act, including conflict of interest replete in the regulator being the regulated and the dual role of the regulator in maximizing revenue and risk governance. Another defect is the retention of a prescriptive method of regulation, which was argued to be ineffective in regulating an ever-evolving risk environment. It is expected that such analyses will prove useful in guiding future reforms in the Nigerian petroleum sector, as well as other jurisdictions, given that risk regulation is an area of transnational law. The authors recommend the adoption of goal-setting risk governance regulation, which allows for flexibility, leaving safety in the hands of those with better expertise to guarantee it, i.e. the operator.

Erosion experiments of shale using a cavitation jet

Cavitation jet has been successfully utilized in onshore and offshore petroleum engineering. In this work, the feasibility of using a cavitation jet to drill and stimulate a shale gas reservoir is investigated. Erosion experiments of shale are conducted under various hydraulic conditions. It is found that the optimal standoff distance linearly increases with upstream pressure. As the upstream pressure increases from 40 MPa to 80 MPa, the maximum erosion rate rises from 0.80 mg/min to 2.22 mg/min. An incubation stage is not observed because of the poor ductility and malleability of shale. Under an upstream pressure of 60 MPa, the maximum cumulative erosion rate at unit jet power achieves the highest value of 1.40×10−3 mg·min−1·W−1. For shale drilling, a higher pump pressure is always in favor of a greater erosion rate, but the nozzle location needs to be adjusted to meet with the optimal standoff distance. For reservoir stimulation, an erosion time of 20 min is recommended. The promoted permeability is mainly attributed to the micro pores and fractures. Besides, the erosion mechanism is discussed concerning the periodic behavior and shedding frequency of cavitation cloud, as well as the development process of erosion pit on shale.

Impact of flow field resolution on produced water transport in Lagrangian and Eulerian models

During offshore petroleum production, large volumes of produced water are continuously discharged. The environmental impact from such discharges is typically assessed with numerical models, which simulate the transport and dilution of the produced water plume in order to predict environmental concentrations of its chemical constituents. In this study we investigate the effects of model resolution (800 m and 4 km) on produced water dispersion. We also compare two different types of models, a Lagrangian particle model, and an Eulerian grid-based ocean model to assess the Eulerian consistency of the Lagrangian model. We consider a point source off the coast of mid-Norway, during two different seasons (winter and spring). In general, the two models are in reasonable agreement. We find a substantial difference in tracer distribution and concentrations between the two resolutions, and to a lesser extent between seasons; in particular, the 800 m model shows lower concentrations along the coast.