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Purpose: The purpose of this study is to provide ideas and theoretical guidance for green, environmentally friendly and efficient "bacteriostasis with bacteria" technology. Design/methodology/approach: In this paper, a beneficial strain of bacteria was extracted and purified from marine mud. Weight-loss test, morphological observation and electrochemical test were used to systematically study the effect of sulfate-reducing bacteria (SRB)-induced corrosion inhibition on X65 steel in simulated offshore oil field production water. Findings: The results showed that a beneficial strain was selected and identified as Vibrio alginolyticus. Under the condition of co-culture of SRB, the average corrosion rate of X65 steel was significantly reduced. In the mixed bacterial system, the surface of X65 steel samples was relatively flat, and the structure of biofilm and corrosion product film was dense. The number of corrosion pits, the average diameter and depth of corrosion pits were significantly reduced. The localized corrosion of X65 steel was significantly inhibited. Originality/value: The complex and changing marine environment makes the corrosion problem of marine steel increasingly severe, and the microbiologically influenced corrosion (MIC) caused by SRB is particularly serious. The research and development of environmentally friendly corrosion protection technology is a long-term and difficult problem. The use of beneficial microorganisms to control MIC is a green and efficient anticorrosion measure. Compared with terrestrial microorganisms, marine microorganisms can adapt to complex environments, and their metabolites exhibit special biological activities. The use of marine beneficial bacteria can inhibit SRB activity to achieve the corrosion inhibition effect. [ABSTRACT FROM AUTHOR]

At present, many offshore oil fields are facing problems, such as pollution-induced near-well zone blockage, poor inter-well connectivity, and strong vertical heterogeneity, which lead to insufficient formation energy and low production in the middle and late stages of development. It is necessary to develop a new technology to overcome these issues. In this regard, water-injection-induced dilation technology, which was already proven to have positive effects on loose sandstone reservoirs, was controversially applied to an offshore low-permeability reservoir. To investigate whether the water-injection-induced dilation technology is suitable, experiments were conducted to analyze the dilation potential of offshore low-permeability sandstone reservoirs, namely, X-ray diffraction, laser particle size analysis, physical simulation, computed tomography scan, and electron microscope scanning experiments. The X-ray diffraction experiments showed that the samples had more than 80% non-clay mineral content and a high brittleness index, which meant more complex microfractures under water injection. Particle size analysis experiments revealed that the particle size was mainly between 10 μm and 100 μm, and thus belonged to coarse silty sand. According to the sorting grade, the sample particle size distribution was uniform and the reservoir was more prone to dilation. The true triaxial physical simulation showed that a volumetric dilation zone occurred around the wellbore, where complicated microfractures occurred. This paper provides adequate evidence and mechanisms of dilation potential for an offshore low-permeability sandstone reservoir. [ABSTRACT FROM AUTHOR]

During the drilling process of horizontal wells in offshore oil fields, when encountering highly clayey shale or sandy shale sections, a common practice is to use a combination of blank pipes and screen pipes in the completion column to isolate high clay content layers. This helps prevent significant clay blockage in the screen pipes or wellbore, thereby reducing production loss. However, when blank pipes cannot effectively isolate clayey or sandy shale sections, the migration of clay content can lead to screen pipe blockage, adversely affecting production capacity. Given the current lack of evaluation methods for the impact of combined blank and screen pipe completion columns on production capacity, an experiment was designed to evaluate the skin factor of the completion column with a combination of blank and screen pipes. Through the calculation of the skin factor, the variation patterns of the skin factor for completion columns with blank and screen pipes under different conditions were obtained. These findings were then applied to a production evaluation. The research results revealed the following: (1) As the proportion of blind pipes increases, the skin factor of the combination of blind pipes and screen pipes in the completion tubing also increases. Excessive blind pipe ratios reduce production capacity. (2) In cases where the annular space is not completely filled, the influence of the blind pipe proportion on production capacity can be negligible. However, when the annular space is 100% filled, a higher proportion of blind pipes and silt content results in a larger skin factor, which leads to reduced production. In the application of the XH horizontal well case study, using the calculated model for the skin factor of the combination of blind pipes and screen pipes in the completion tubing established in this paper, it was determined that when the annular space was not completely blocked and 20 m of blind pipes were not placed in the designated position, the impact on the production index was 0.73%. However, when the blind pipes were not placed in the designated position for 100 m, the impact on the production index reached 1.47%. The method developed in this paper provides theoretical guidance for the optimization of completion tubing in mudstone and sandy mudstone sections and for production evaluation. [ABSTRACT FROM AUTHOR]

Cleanup of oil spills has become one of the most challenging tasks in recent years, as marine oil spills have had a great negative impact on human health and the ecological environment. This also urgently requires the development of new materials and methods with superhydrophobic properties for oil-water separation. As new porous materials, metal-organic frameworks (MOFs) have attracted much attention due to their unique structures and fascinating properties. However, powdered MOF materials are difficult to recycle, and therefore, suitable substrates need to be selected to construct superhydrophobic composites. The surface hydroxyl groups of cellulose fibers offer great possibilities for their superhydrophobic preparation. In this paper, HDTMS-UiO-66@CFs composites with superhydrophobicity were strategically synthesized by in-situ growth of Zr(IV)-based MOFs linked to hexadecyltrimethoxysilane (HDTMS) on cellulosic fibers (cotton fabric) by using a hydrothermal synthesis method. The HDTMS-UiO-66@CFs composites have a water contact angle of 172[degrees] and the absorption capacity of light oil and heavy oil is more than 1100%, and the oilwater separation efficiency is as high as 96%. Due to the in-situ growth of the HDTMS-UiO-66 material on cotton fibers, which makes the material more resistant and stable, the material can still maintain its superhydrophobic properties in various harsh environments and after repeated use. Therefore, the newly developed HDTMS-UiO-66@CFs composites have a high potential as novel adsorbent materials for cleaning up offshore oil spills and other applications. Highlights * In-situ growth of superhydrophobic metal-organic frameworks (MOF) particles on cellulose fibers. * The porous structure of hexadecyltrimethoxysilane (HDTMS)-Ui066 plays a key role in hydrophobicity. * HDTMS-Ui066@CFs are chemically stable and have long-term durability. KEYWORDS cotton fabrics, hydrophobicity, oil-water separation, zirconium-based metal-organic framework, 1 | INTRODUCTION Marine oil pollution is immensely harmful. Its damage to biodiversity, aquatic ecosystems, coastal and marine ecosystems is serious and ongoing. (1) At the same time, oil pollution [...]

There is currently a rising interest in reusing and repurposing offshore facilities through decommissioning; however, major challenges arise, such as size, weight, sea depth, planned use, and location. This article aims to discuss the philosophy that needs to be adopted for field redevelopment, particularly when existing platforms must be preserved and integrated into new greenfield facilities. The article also discusses the concept of weight shedding during the decommissioning of offshore facilities to either extend the life of existing platforms or provide clear space for new equipment to be installed by removing unnecessary components and structures. The above aspects of decommissioning are investigated through the redevelopment of a case study of a mature offshore oil field located in shallow water. The study indicated that weight shedding presents a favourable method for decommissioning offshore installations and can effectively lower expenses, minimise environmental consequences, and optimise the use of resources. [ABSTRACT FROM AUTHOR]

Remotely operated vehicle (ROV) is a widely used subsea vehicle in offshore oil and gas industries to assist in the development and inspection of offshore oil fields, given its agility, safety, and endurance. As the offshore industry and subsea engineering fields advance, the demands on ROV technology, particularly in terms of control accuracy and safety, have been greatly increasing. Traditional methods require ROV operators to be stationed on vessels in challenging conditions, relying on video streams that offer limited spatial information about the ROV working environment. All these factors make conventional joystick controls even harder for novices. This research aims to propose a novel approach to human-autonomy collaboration aiming to diminish the learning and operational burdens on operators. A virtual reality (VR)-based sensory augmentation and body motion teleoperation method was applied, which allows operators to teleoperate the ROV in a much more comfortable environment. An interactive user interface was developed to enable seamless engagement with the autonomous system and facilitate dynamic switching between human and autonomous controls. To assess the system, a human subject experiment was conducted to compare the performance of an inspection task between human control, full autonomy, and human autonomy teaming methods. The result indicated that our solution could enhance human understanding of the ROV work status as well as reduce human workload during operation. [ABSTRACT FROM AUTHOR]

Copyright of China Sciencepaper is the property of China Sciencepaper and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The development of offshore oil fields confronts challenges associated with high water cut and low displacement efficiency. Reservoir injection-production optimization stands out as an effective means to reduce costs and enhance efficiency in offshore oilfield development. The process of optimizing injection and production in offshore oil reservoirs involves designing strategies for a large number of wells and optimization time steps, constituting a large-scale, complex, and costly optimization computation problem. In recent years, with the rapid advancements in big data and artificial intelligence technologies, sophisticated evolutionary computation methods have found widespread application in reservoir injection-production optimization problems. However, the abundance of intelligent optimization algorithms raises the question of how to choose a method suitable for the complex optimization background of offshore oilfield injection-production optimization. This paper provides a detailed overview of the application of an existing differential evolution algorithm (DE), conventional surrogate-assisted evolutionary algorithm (CSAEA), and global–local surrogate-assisted differential evolution (GLSADE) in the context of practical offshore oilfield injection-production optimization problems. A comprehensive comparison of their performance differences is presented. The study concludes that the global–local surrogate-assisted evolutionary algorithm is the most suitable method for addressing the current challenges in offshore oilfield injection-production optimization. [ABSTRACT FROM AUTHOR]

X65 pipeline steel is widely used in the field of offshore oil and gas exploitation due to its excellent performance. However, due to the complex environment in the ocean, X65 pipeline steel is faced with a great risk of microbial corrosion failure. Therefore, it is of great significance to study the corrosion mechanism of X65 pipeline steel by microorganisms. In this paper, the corrosion effect of Pseudomonas aeruginosa (P. aeruginosa) secreting phenazine compounds on X65 pipeline steel was studied by the weight loss method, biofilm scanning electron microscopy analysis, surface corrosion morphology observation, electrochemical testing and medium pH test corrosion products. The results showed that the inoculation of P. aeruginosa accelerated the corrosion of X65 steel. After knocking out the phzM and phzS genes that regulate the synthesis of PYO, P. aeruginosa can still produce biofilms on the surface of X65 steel consistent with the morphology of wild-type P. aeruginosa, but the corrosion of X65 steel is significantly reduced. It is proved that PYO plays an important role in the corrosion process of P. aeruginosa on steel. [ABSTRACT FROM AUTHOR]

Carbonate reservoirs hold vast oil reserves, but their complex properties make traditional enhanced oil recovery (EOR) methods challenging. This study explores the application of low-salinity water flooding (LSWF) as a novel EOR method for India's largest offshore carbonate oil field. Conventional EOR techniques were deemed unsuitable due to reservoir heterogeneity, pressure decline, high temperature, and the offshore location. Favorable factors for LSWF included successful seawater flooding history, medium-weight crude oil, and existing infrastructure. Following core flooding experiments demonstrating a 6–16% increase in oil recovery, a multi-pronged evaluation process was implemented. Single-well chemical tracer tests (SWCTT) and reservoir simulations confirmed the potential of LSWF. A specific target area was chosen based on reservoir characteristics, production data, and available facilities. Simulations predicted a 1.5% incremental oil recovery using diluted seawater (25% salinity) at 30% pore volume injection. After a positive techno-economic analysis, the first offshore LSWF project in India was completed within 3 years. Initial monitoring results are encouraging. This study highlights the successful journey of LSWF from concept to field deployment in a challenging carbonate reservoir, showcasing its potential for revitalizing such fields. Furthermore, this work provides valuable data relevant to Indian offshore environments, where factors like salinity, mineralogy, and crude oil composition pose unique challenges compared to other LSWF applications. These detailed data fill a critical gap in the existing literature. [ABSTRACT FROM AUTHOR]

Traditional technologies of oil production on the land and the sea shelf have low coefficient of oil recovery, thus cause a huge loss to environment to what become frequent oil spills testify worldwide. In article the innovative way of development of oil fields allowing to increase significantly oil recovery by means of artificially created gravitational mode is described and also completely to exclude environmental pollution when developing offshore fields thanks to oil production by a dense grid of wells which are drilled from horizontal wells. In comparison with usual ways of oil production on the shelf, such as development, from bulk islands, oil platforms and platforms, this way has a number of technological and economic advantages. Experience of application of similar technologies around the world is considered. For comparison outputs of wells and capital expenditure on the example of oil fields Kyrykmyltyk and Kashagan in Kazakhstan are counted. [ABSTRACT FROM AUTHOR]

In June 2023, Israel approved the development of Gaza Marine, a small offshore gas field near the Gaza Strip that has remained dormant since its discovery in 2000. The field can potentially benefit the Palestinian Authority (PA) in terms of export revenue and energy independence. However, the legal status of the field remains unclear, and the 2023 Israel–Hamas war further complicated this matter. On the one hand, although Israel has not made any legal claim to Gaza Marine, its approval to develop the field is still considered necessary by all parties involved. On the other hand, while the PA views itself as the rightful owner of the field, it has had no effective control over Gaza's coastline or waters since 2007, weakening its claim. This article reviews the complex history and evolving legal status of the Gaza Marine gas field up until the 2023 war. It argues that there is still room for optimism regarding the future development of the field, especially when considering its similarities to the successful 2022 maritime agreement between Israel and Lebanon. [ABSTRACT FROM AUTHOR]

The subsea control system, a pivotal element of the subsea production system, plays an essential role in collecting production data and real-time operational monitoring, crucial for the consistent and stable output of offshore oil and gas fields. The increasing demand for secure offshore oil and gas extraction underscores the necessity for advanced reliability modeling and effective maintenance strategies for subsea control systems. Given the enhanced reliability of subsea equipment due to technological advancements, resulting in scarce failure data, traditional reliability modeling methods reliant on historical failure data are becoming inadequate. This paper proposes an innovative reliability modeling technique for subsea control systems that integrates a Wiener degradation model affected by random shocks and utilizes the Copula function to compute the joint reliability of components and their backups. This approach considers the unique challenges of the subsea environment and the complex interplay between components under variable loads, improving model accuracy. This study also examines the effects of imperfect maintenance on degradation paths and introduces a holistic lifecycle cost model for preventive maintenance (PM), optimized against reliability and economic considerations. Numerical simulations on a Subsea Control Module demonstrate the effectiveness of the developed models. [ABSTRACT FROM AUTHOR]

Operations and maintenance (O&M) of floating offshore wind turbines (FOWTs) require regular inspection activities to predict, detect, and troubleshoot faults at high altitudes and in harsh environments such as strong winds, waves, and tides. Their costs typically account for more than 30% of the lifetime cost due to high labor costs and long downtime. Different inspection methods, including manual inspection, permanent sensors, climbing robots, remotely operated vehicles (ROVs), and unmanned aerial vehicles (UAVs), can be employed to fulfill O&M missions. The UAVs, as an enabling technology, can deal with time and space constraints easily and complete tasks in a cost-effective and efficient manner, which have been widely used in different industries in recent years. This study provides valuable insights into the existing applications of UAVs in FOWT inspection, highlighting their potential to reduce the inspection cost and thereby reduce the cost of energy production. The article introduces the rationale for applying UAVs to FOWT inspection and examines the current technical status, research gaps, and future directions in this field by conducting a comprehensive literature review over the past 10 years. This paper will also include a review of UAVs' applications in other infrastructure inspections, such as onshore wind turbines, bridges, power lines, solar power plants, and offshore oil and gas fields, since FOWTs are still in the early stages of development. Finally, the trends of UAV technology and its application in FOWTs inspection are discussed, leading to our future research direction. [ABSTRACT FROM AUTHOR]

It is an important function of submarine pipeline flow assurance system to monitor undesirable gas-liquid flow patterns in pipeline in real time, and release early warning ahead of the formation of these flow patterns. In order to tackle the problem of existing method that requires a large training set, and A method of self-adaptive early warning of transition to unstable regime is developed based on transient experiment of gas-liquid two-phase flow performed on a 150-m-long laboratorial pipeline-riser system. The responses of different differential pressure signals were investigated first, so as to pick out the optimum ones used for early warning. Then, the long-short time memory (LSTM) neural network combined with empirical mode decomposition (EMD) was adopted to judge transient condition. In the next step, a series of EMD-LSTM models were trained in order to predict whether undesirable flow pattern would occur, and the warning would be released if the result was 'yes'. Within the range of experiments, all transient cases were correctly judged. The principles of proposed method were then tested and verified by data from a longer laboratorial pipeline-riser system and an offshore oil field, indicating good adaptability of the method. • Indicators (signals) for early warning of undesirable flow patterns are selected. • Two levels of judging process are setup to meet the defense-in-depth principle. • Long-time flow parameters are predicted by LSTM neural network. • The method does not need a trained flow pattern recognition model. • The principles of the method are verified by laboratorial and field data. [ABSTRACT FROM AUTHOR]

In recent years, the development of two offshore low-permeability oil fields has revealed unexpected challenges. The actual productivity of these fields significantly deviates from the designed capacity. Some wells even outperform the expectations for low-permeability limestone fields. This discrepancy primarily stems from a lack of accurate understanding of natural fractures before and after drilling, resulting in substantial errors in capacity assessment. This paper addresses these challenges by proposing a new production capacity model and evaluation method for both vertical and horizontal wells in low-permeability limestone reservoirs. The method leverages logging curve data, incorporating vertical gradation and fractal analysis to effectively represent the fracture's complexity and connectivity. It uniquely considers factors such as fracture fractal dimensions, threshold pressure, and stress sensitivity, significantly enhancing prediction accuracy. Furthermore, by analyzing the longitudinal gradient in logging curves, the method effectively identifies strong heterogeneity, leading to more accurate capacity evaluations in actual fields. The results demonstrate that our model reduces the average prediction error to less than 15%, markedly outperforming traditional methods. Calculation results of the newly developed capacity formula align closely with actual production data and tracer test results, showcasing its practical applicability and potential for widespread use. This study notably advances the evaluation of reasonable production capacity in similar offshore reservoirs. [ABSTRACT FROM AUTHOR]

In water flooding, residual oil is displaced by injecting water into the reservoir formation. Oil displaced from injection wells is physically swept to adjacent production wells by water. Compared to conventional oil fields, offshore heavy oil fields have low oil recovery using water flooding. If we had a better knowledge of the flow characteristics of the water and oil phases, it would be very useful to improve the oil recovery of the heavy oil reservoir. In developing oil fields, it is important to study the patterns of changes in the flow characteristics of the oil and water phases. This will guide the development of numerical simulation models. This study considered the geological characteristics, fluid properties, and construction technology of an offshore oil field with heavy oil. The relative permeabilities of water and oil were investigated using steady-state and unsteady-state methods. With the unsteady state method, the effect of core permeability, water washout, and oil viscosity on the relative permeability curve and oil displacement efficiency of water flooding has been investigated. Artificial cores were utilized in the experiments. The artificial cores were developed to simulate the structure of unconsolidated sandstone in an offshore oil field. Computed tomography and mercury pressure testing are used to demonstrate the change in the internal structure of the core. Water washout forms the “cleaning” and “erosion” function, which affects core pore structure, increases the radius of the core pore throat, and increases the core permeability. It has the same effect on relative permeability curves and oil displacement efficiency as it does on increased permeability. The total oil recovery decreases with increasing oil viscosity since the ability to control water mobility weakens during the flooding process. Moreover, the coverage volume of the displacing water phase decreases, and the two-phase flow range narrows Water sweeps expand as core permeability increases, resulting in a wider twophase flow as the relative permeability of the water phase increases. In turn, this enhances oil efficiency displacement and total oil recovery. [ABSTRACT FROM AUTHOR]

Copyright of Rudarsko-Geolosko-Naftni Zbornik is the property of Faculty of Mining, Geology & Petroleum Engineering and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The significance of the Production Sharing Contract (PSC) for the onshore and offshore extraction of petroleum resources from Bangladesh's sovereign territory has grown in recent years due to maritime delimitations among its neighbouring countries. To ensure the long-term investment, social well-being, economic growth, and energy stability of the country, the Government of Bangladesh (GoB) has introduced the Model Offshore Production Sharing Contract (PSC)-2023. This article aims to provide an analysis of the Model PSC-2023. Through a thorough examination of the Model PSC-2023, it will address any existing loopholes and provide recommendations for its improvement. This article will be instrumental in launching the future development of the offshore model offshore production sharing contract. [ABSTRACT FROM AUTHOR]

Renewable energy sources have been utilized by countries worldwide, but offshore energy exploitation projects remain highly promising for both the world and New Zealand specifically. The selection of equipment installation locations can be challenging and requires significant investment, prompting the need for optimization in offshore energy exploitation. Wind and wave location (WWL) integrated sites offer a highly potential solution for reducing installation costs and enhancing efficiency in renewable energy exploitation. However, the decision‐making process for selecting equipment locations is crucial and directly affects the outcome. This study aims to evaluate and consider sustainable and effective equipment installation sites based on both quantitative indicators and behavioral psychology of decision making. To achieve this goal, the study utilizes the prospect theory Data Envelopment Analysis (PT‐DEA) model, which builds on PT to analyze and evaluate the effectiveness of offshore installation site selection with consideration for human psychology. By combining the results of quantitative indicators and decision‐making behavior, the study identifies sustainable and effective offshore installation sites, recommending appropriate equipment installation locations WWL. The study is also compared and referenced with relevant plans, projects, and development policies in New Zealand for confirmation. [ABSTRACT FROM AUTHOR]

Decommissioning of offshore petroleum installations is innately risky and adversely affects the livelihoods of fishing communities' dependent on access to the marine resources. However, it remains unclear how Ghana's legislative framework addresses the protection of local livelihoods during the decommissioning of its first offshore installation, the Saltpond Oil and Gas Field. We designed a case study to explore the legislative responses and impact of decommissioning on the livelihoods of fishers in five affected fishing communities in the Mfantseman Municipality of the Central Region of Ghana. The primary data used in this study was through the survey of 191 fishers and interview of representatives of state institutions relevant to this study. We found that Ghana's legislative framework for decommissioning did not adequately address negative impacts on local fishing communities whose livelihoods were greatly disrupted due to these activities. We recommend that detailed guidelines are incorporated in the legislative framework before further decommissioning is undertaken and that the government provide alternative livelihood options to the impacted communities. [ABSTRACT FROM AUTHOR]

• The transient temperatures consist of the steady state and filtered homogeneous transient solutions with Bessel functions. • A general solution is given for the transient thermomechanical axisymmetric problem of TCP. • The thermal stresses of TCP under axisymmetric loadings are obtained by the temperature instantaneous interpolation method. • The pipe temperatures and stresses progress from the initial towards the steady states during the warming up/cooling down. • The failure indexes of TCP transient thermomechanical axisymmetric model are below the initial or steady state values. Thermoplastic composite pipe (TCP) is a promising design concept for offshore sour oil fields. The bonded structure typically consists of inner and outer homogeneous isotropic polymeric layers and intermediate transversely isotropic laminate ply layers. A theoretical transient thermomechanical analysis under axisymmetric loadings and thermal gradient subjected to convective heat transfers at the inner and outer surfaces is presented. For the heat conduction problem in a multilayer composite pipe, the transient temperature is expressed as a combination of steady state and filtered homogeneous transient solutions employing Bessel's functions. The general solution for the TCP thermomechanical axisymmetric model is also derived. An instantaneous temperature interpolation of the exact interlayer values is employed for the thermal stress analysis to overcome the difficulty of the double integration of Bessel's functions. The von Mises stress and Maximum Stress are respectively applied as failure criteria for the isotropic and laminate layers. During the warming up and cooling down, the through-thickness temperatures and stresses gradually progress from the initial towards the final steady state regime. The thermomechanical transient response is dominated by mechanically induced stresses. The transient failure indexes are below the initial and steady state values for the axisymmetric mechanical and thermal loadings during the selected warm up or cool down conditions. [ABSTRACT FROM AUTHOR]