Water Injection Pipeline Repair Offshore Angola Enhances Production

2021 ◽  
Author(s):  
Kamil Sobolewski
Keyword(s):  
Water Injection ◽  
Surface Cleaning ◽  
Second Phase ◽  
Element Analysis ◽  
Reduced Pressure ◽  
Area Survey ◽  
Coating Removal ◽  
Multiple Challenges ◽  
Mechanical Tool ◽  
The Impact

Abstract An international operating company detected a leak during an annual ROV inspection of a water injection (WI) pipeline offshore Angola in the Gulf of Guinea. The pipeline owner made the decision to repair the damaged line using clamps, but there were multiple challenges involved in executing the repair. First was the depth of the pipeline, which was on the seabed across an area that ranged from 1,170 m to 1,410 m (3,839 ft – 4,626 ft). Additional challenges included potential complications for clamp installation because of the location of the pipe welds and the physical condition of the pipe, which had experienced considerable wall thinning in multiple areas. Bringing the pipeline back into safe service required repairs to the aging pipe within a scope of work that included site preparation, the installation of two 12-in clamp connectors, and inspection services following clamp placement to verify proper installation. Because there were welds in the WI pipeline, there was a risk that the clamp installation site would correspond with an area of the pipe that was welded, which would impact the ability of the clamps to fit snugly over the damaged area. Survey data were cross-referenced with the client's data to determine that the weld locations would not interfere with the installation. Coating removal was critical, so a purpose-built mechanical tool was designed to prepare the pipeline for clamp installation. The project also required finite element analysis (FEA) to confirm that the pipeline could withstand the seal load applied by the repair clamps. The project was carried out in three steps. The objective of the first step was to prepare and stabilize the seabed to ensure it could bear the weight of the clamp installation frame and the impact of the ROV working nearby. The second phase focused on preparing the repair locations for installation of the clamps, a process that included coating removal and surface cleaning to return the WI pipeline to bare metal finish in the clamp areas. The third phase was the preparation and installation of the 12-in repair clamps. This included the inspection and spot cleaning of pipeline surfaces, clamp installation, and clamp seal verification. The two clamps were successfully installed and passed pressure testing in February 2020, enabling the operator to bring the WI line back online and functioning safely at reduced pressure. This repair employed the highest-pressure clamp of this type installed to date (138 bar / 2,000 psi).

scholarly journals Potential and limitations of finite element modelling in assessing structural integrity of coralline algae under future global change

2015 ◽  
Vol 12 (19) ◽  
pp. 5871-5883 ◽  
Author(s):  
L. A. Melbourne ◽  
J. Griffin ◽  
D. N. Schmidt ◽  
E. J. Rayfield
Keyword(s):  
Climate Change ◽  
Finite Element ◽  
Structural Integrity ◽  
Geometric Model ◽  
Algal Growth ◽  
Coralline Algae ◽  
Rocky Shores ◽  
Element Analysis ◽  
Scan Data ◽  
The Impact

Abstract. Coralline algae are important habitat formers found on all rocky shores. While the impact of future ocean acidification on the physiological performance of the species has been well studied, little research has focused on potential changes in structural integrity in response to climate change. A previous study using 2-D Finite Element Analysis (FEA) suggested increased vulnerability to fracture (by wave action or boring) in algae grown under high CO2 conditions. To assess how realistically 2-D simplified models represent structural performance, a series of increasingly biologically accurate 3-D FE models that represent different aspects of coralline algal growth were developed. Simplified geometric 3-D models of the genus Lithothamnion were compared to models created from computed tomography (CT) scan data of the same genus. The biologically accurate model and the simplified geometric model representing individual cells had similar average stresses and stress distributions, emphasising the importance of the cell walls in dissipating the stress throughout the structure. In contrast models without the accurate representation of the cell geometry resulted in larger stress and strain results. Our more complex 3-D model reiterated the potential of climate change to diminish the structural integrity of the organism. This suggests that under future environmental conditions the weakening of the coralline algal skeleton along with increased external pressures (wave and bioerosion) may negatively influence the ability for coralline algae to maintain a habitat able to sustain high levels of biodiversity.

Impact Load Buffering Method Based on Stress Wave Attenuation Principle

2019 ◽  
Vol 11 (02) ◽  
pp. 1950019 ◽  
Author(s):  
Lin Gan ◽  
He Zhang ◽  
Cheng Zhou ◽  
Lin Liu
Keyword(s):  
Stress Wave ◽  
Wave Attenuation ◽  
Impact Load ◽  
Dynamics Simulation ◽  
Scanning System ◽  
Isolation Method ◽  
Element Analysis ◽  
System A ◽  
High Emission ◽  
The Impact

Rotating scanning motor is the important component of synchronous scanning laser fuze. High emission overload environment in the conventional ammunition has a serious impact on the reliability of the motor. Based on the theory that the buffer pad can attenuate the impact stress wave, a new motor buffering Isolation Method is proposed. The dynamical model of the new buffering isolation structure is established by ANSYS infinite element analysis software to do the nonlinear impact dynamics simulation of rotating scanning motor. The effectiveness of Buffering Isolation using different materials is comparatively analyzed. Finally, the Macht hammer impact experiment is done, the results show that in the experience of the 70,000[Formula: see text]g impact acceleration, the new buffering Isolation method can reduce the impact load about 15 times, which can effectively alleviate the plastic deformation of rotational scanning motor and improve the reliability of synchronization scanning system. A new method and theoretical basis of anti-high overload research for Laser Fuze is presented.

scholarly journals Does Multidisciplinary Team Simulation-Based Training Improve Obstetric Emergencies Skills?

Healthcare ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 170
Author(s):  
Encarna Hernández ◽  
Marcos Camacho ◽  
César Leal-Costa ◽  
María Ruzafa-Martínez ◽  
Antonio Jesús Ramos-Morcillo ◽  
...  
Keyword(s):  
Health Professionals ◽  
Multidisciplinary Team ◽  
Simulation Training ◽  
Observer Agreement ◽  
Second Phase ◽  
High Fidelity ◽  
Breech Delivery ◽  
Obstetric Emergencies ◽  
Quasi Experimental ◽  
The Impact

Clinical simulation in obstetrics has turned out to be a tool that can reduce the rate of perinatal morbidity and mortality. The objective of this study was to analyze the impact and evaluate the effects of training with high-fidelity simulation of obstetric emergencies on a multidisciplinary group. The quasi-experimental research study was structured in three phases: a first phase where the most important obstetric emergencies were determined, a second phase of design and development of the selected cases for simulation training, and a third and final phase where the abilities and satisfaction of the multidisciplinary team were analyzed. Three scenarios and their respective evaluation tools of obstetric emergencies were selected for simulation training: postpartum hemorrhage, shoulder dystocia, and breech delivery. The health professionals significantly improved their skills after training, and were highly satisfied with the simulation experience (p < 0.05). An inter-observer agreement between good and excellent reliability was obtained. Regarding conclusions, we can state that high-fidelity obstetric emergency simulation training improved the competencies of the health professionals.

scholarly journals The Clean pilot study: evaluation of an environmental hygiene intervention bundle in three Tanzanian hospitals

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Giorgia Gon ◽  
Abdunoor M. Kabanywanyi ◽  
Petri Blinkhoff ◽  
Simon Cousens ◽  
Stephanie J. Dancer ◽  
...  
Keyword(s):  
Pilot Study ◽  
Study Design ◽  
Low Income ◽  
High Volume ◽  
Surface Cleaning ◽  
Low Income Countries ◽  
Training Period ◽  
Future Research ◽  
Environmental Hygiene ◽  
The Impact

Abstract Background Healthcare associated infections (HAI) are estimated to affect up to 15% of hospital inpatients in low-income countries (LICs). A critical but often neglected aspect of HAI prevention is basic environmental hygiene, particularly surface cleaning and linen management. TEACH CLEAN is an educational intervention aimed at improving environmental hygiene. We evaluated the effectiveness of this intervention in a pilot study in three high-volume maternity and newborn units in Dar es Salaam, Tanzania. Methods This study design prospectively evaluated the intervention as a whole, and offered a before-and-after comparison of the impact of the main training. We measured changes in microbiological cleanliness [Aerobic Colony Counts (ACC) and presence of Staphylococcus aureus] using dipslides, and physical cleaning action using gel dots. These were analysed with descriptive statistics and logistic regression models. We used qualitative (focus group discussions, in-depth interviews, and semi-structured observation) and quantitative (observation checklist) tools to measure why and how the intervention worked. We describe these findings across the themes of adaptation, fidelity, dose, reach and context. Results Microbiological cleanliness improved during the study period (ACC pre-training: 19%; post-training: 41%). The odds of cleanliness increased on average by 1.33 weekly during the pre-training period (CI = 1.11–1.60), and by 1.08 (CI = 1.03–1.13) during the post-training period. Cleaning action improved only in the pre-training period. Detection of S. aureus on hospital surfaces did not change substantially. The intervention was well received and considered feasible in this context. The major pitfalls in the implementation were the limited number of training sessions at the hospital level and the lack of supportive supervision. A systems barrier to implementation was lack of regular cleaning supplies. Conclusions The evaluation suggests that improvements in microbiological cleanliness are possible using this intervention and can be sustained. Improved microbiological cleanliness is a key step on the pathway to infection prevention in hospitals. Future research should assess whether this bundle is cost-effective in reducing bacterial and viral transmission and infection using a rigorous study design.

scholarly journals Fragility assessment of existing low-rise steel moment-resisting frames with masonry infills under mainshock-aftershock earthquake sequences

2021 ◽  
Vol 19 (6) ◽  
pp. 2483-2504
Author(s):  
Luigi Di Sarno ◽  
Jing-Ren Wu
Keyword(s):  
Seismic Vulnerability ◽  
Steel Frames ◽  
Steel Frame ◽  
Second Phase ◽  
Moment Frames ◽  
Damage Level ◽  
Masonry Infills ◽  
Aftershock Sequences ◽  
The Impact ◽  
Multiple Earthquakes

AbstractThis paper presents the fragility assessment of non-seismically designed steel moment frames with masonry infills. The assessment considered the effects of multiple earthquakes on the damage accumulation of steel frames, which is an essential part of modern performance-based earthquake engineering. Effects of aftershocks are particularly important when examining damaged buildings and making post-quake decisions, such as tagging and retrofit strategy. The procedure proposed in the present work includes two phase assessment, which is based on incremental dynamic analyses of two refined numerical models of the case-study steel frame, i.e. with and without masonry infills, and utilises mainshock-aftershock sequences of natural earthquake records. The first phase focuses on the undamaged structure subjected to single and multiple earthquakes; the effects of masonry infills on the seismic vulnerability of the steel frame were also considered. In the second phase, aftershock fragility curves were derived to investigate the seismic vulnerability of infilled steel frames with post-mainshock damage caused by mainshocks. Comparative analyses were conducted among the mainshock-damaged structures considering three post-mainshock damage levels, including no damage. The impact of aftershocks was then discussed for each mainshock-damage level in terms of the breakpoint that marks the onset of exceeding post-mainshock damage level, as well as the probability of exceeding of superior damage level due to more significant aftershocks. The evaluation of the efficiency of commonly used intensity measures of aftershocks was also carried out as part of the second phase of assessment.

scholarly journals Effect of Short-Term Carbapenem Restriction on Antimicrobial Susceptibility of Resistant Gram-Negative Bacilli in an ICU

2020 ◽  
Vol 41 (S1) ◽  
pp. s200-s201
Author(s):  
Mariana Melo ◽  
Raquel Bandeira ◽  
lio de Castro Giselle Dias ◽  
Braulio Couto
Keyword(s):  
High Mortality ◽  
Bacterial Resistance ◽  
Statistical Significance ◽  
Public Health Problem ◽  
Resistance Rate ◽  
Second Phase ◽  
Short Term ◽  
Intervention Phase ◽  
Carbapenem Resistant ◽  
The Impact

Background: Carbapenem-resistant GNB infections are a serious public health problem worldwide, particularly due to the high mortality associated with them and the low number of therapeutic options. One approach to this challenge is the development of antimicrobial stewardship programs. Objective: We evaluated the impact of a carbapenem restriction program on reducing of bacterial resistance in an intensive care unit (ICU). Methods: A retrospective study conducted in 2 phases in the 80-bed ICU of an acute-care public hospital in Minas Gerais, Brazil. The preintervention phase lasted 16 months (January 2018–April 2019) and the second phase (carbapenem restriction), after the intervention, lasted 4 months (May–August 2019). The intervention was defined as carbapenem-sparing and the use of meropenem was authorized in 3 situations: (1) treatment of serious infections documented by extended-spectrum β-lactamase–producing Enterobacteriacea (ESBL); (2) therapeutic failure with the use of another antimicrobial; and (3) infectious disease recommendation. Data were obtained through consultation of electronic medical records and microbiological results, as standardized by the CLSI, for patients with a >48-hour stay in the ICU and who met the criteria for healthcare-associated infection (HAI) according to the CDC NHSN definition. Results: Before the intervention, on average, 50 cultures were obtained with positive results for multidrug-resistant GNB–MER-GNB (SD, 12.2) and in the intervention phase, this number was 31 cultures (SD, 12.8; P = .010). Average carbapenem consumption decreased significantly with corresponding increase in cefepime consumption in the same period (Fig. 1). The ATB (DDD per 1,000 patient days) before the intervention for carbapenems was 110.6 (SD, 97.1) and for cefepime was 8.2 (SD, 5.9). In the intervention phase, the ATB for carbapenems was 44.7 (SD, 38.5; P = .015) and for cefepime it was 32.0 (SD, 20.3; P < .001). In terms of multidrug resistance rate, before the intervention, 95 of 149 of Acinetobacter (64%) were resistant and during the intervention, 13 of 30 Acinetobacter (43%) were resistant (P = .043). Other GNB (Klebsiella, Proteus, Escherichia coli, and Pseudomonas) reduced the resistance rate, but without statistical significance. We observed a reduction in the HAI rate per MDR-GNB (Fig. 2): before the intervention, it was 22.7 (SD, 5.5) and during the intervention phase it was 16.5 (SD, 7.7; P = .07), although this change did not reach statistical significance. Nevertheless, the ICU Klebsiella infection rate did significantly decrease; it was 5.5 (SD, 1.9) before the intervention and 2.4 (SD, 1.8) after the intervention (P = .009). Conclusions: Short-term carbapenem restriction may be an effective strategy to reduce the incidence of carbapenem-resistant GNB infections in the ICU. The scarce arsenal available for the treatment of MDR-GNB and the high mortality rate justify the growing need for stewardship programs in Brazilian ICUs.Funding: NoneDisclosures: None

scholarly journals Integrative analysis of <i>Geobacter</i> spp. and sulfate-reducing bacteria during uranium bioremediation

2012 ◽  
Vol 9 (3) ◽  
pp. 1033-1040 ◽  
Author(s):  
M. Barlett ◽  
K. Zhuang ◽  
R. Mahadevan ◽  
D. Lovley
Keyword(s):  
Sulfate Reducing Bacteria ◽  
Field Trials ◽  
Second Phase ◽  
Sulfate Reducing ◽  
Organic Electron ◽  
Poor Understanding ◽  
Key Factor ◽  
Reducing Bacteria ◽  
The Impact

Abstract. Enhancing microbial U(VI) reduction with the addition of organic electron donors is a promising strategy for immobilizing uranium in contaminated groundwaters, but has yet to be optimized because of a poor understanding of the factors controlling the growth of various microbial communities during bioremediation. In previous field trials in which acetate was added to the subsurface, there were two distinct phases: an initial phase in which acetate-oxidizing, U(VI)-reducing Geobacter predominated and U(VI) was effectively reduced and a second phase in which acetate-oxidizing sulfate reducing bacteria (SRB) predominated and U(VI) reduction was poor. The interaction of Geobacter and SRB was investigated both in sediment incubations that mimicked in situ bioremediation and with in silico metabolic modeling. In sediment incubations, Geobacter grew quickly but then declined in numbers as the microbially reducible Fe(III) was depleted whereas the SRB grow more slowly and reached dominance after 30–40 days. Modeling predicted a similar outcome. Additional modeling in which the relative initial percentages of the Geobacter and SRB were varied indicated that there was little to no competitive interaction between Geobacter and SRB when acetate was abundant. Further simulations suggested that the addition of Fe(III) would revive the Geobacter, but have little to no effect on the SRB. This result was confirmed experimentally. The results demonstrate that it is possible to predict the impact of amendments on important components of the subsurface microbial community during groundwater bioremediation. The finding that Fe(III) availability, rather than competition with SRB, is the key factor limiting the activity of Geobacter during in situ uranium bioremediation will aid in the design of improved uranium bioremediation strategies.

Response of Mild Steel Pipes Under High Mass Low Velocity Impacts

2014 ◽  
Author(s):  
Shamsoon Fareed ◽  
Ian May
Keyword(s):  
Finite Element ◽  
Mild Steel ◽  
Impact Energy ◽  
High Mass ◽  
Low Velocity ◽  
Element Analysis ◽  
Steel Pipes ◽  
Impact Tests ◽  
The Finite Element Analysis ◽  
The Impact

Accidental loads, for example, due to heavy dropped objects, impact from the trawl gear and anchors of fishing vessels can cause damage to pipelines on the sea bed. The amount of damage will depend on the impact energy. The indentation will be localized at the contact area of the pipe and the impacting object, however, an understanding of the extent of the damage due to an impact is required so that if one should occur in practice an assessment can be made to determine if remedial action needs to be taken to ensure that the pipeline is still serviceable. There are a number of parameters, including the pipe cross section and impact energy, which influence the impact behaviour of a pipe. This paper describes the response, and assesses the damage, of mild steel pipes under high mass low velocity impacts. For this purpose full scale impacts tests were carried out on mild steel pipe having diameter of 457 mm, thickness of 25.4 mm and length of 2000 mm. The pipe was restrained along the base and a 2 tonnes mass with sharp impactor having a vertical downward velocity of 3870 mm/sec was used to impact the pipe transversely with an impact energy of 16 kJ. It was found from the impact tests that a smooth indentation was produced in the pipe. The impact tests were then used for validation of the non-linear dynamic implicit analyses using the finite element analysis software ABAQUS. Deformations at the impact zone, the rebound velocity, etc, recorded in the tests and the results of the finite element analysis were found to be in good agreement. The impact tests and finite element analyses described in this paper will help to improve the understanding of the response of steel pipes under impact loading and can be used as a benchmark for further finite element modelling of impacts on pipes.

Discussion of Oxygen Threshold Level for Corrosion Management in Seawater Injection Systems

2021 ◽  
Author(s):  
Jean Vicente Ferrari
Keyword(s):  
Corrosion Rate ◽  
Oxygen Reduction ◽  
Water Injection ◽  
Steel Corrosion ◽  
Threshold Level ◽  
International Standards ◽  
Limiting Current ◽  
Order Of Magnitude ◽  
The Impact ◽  
Oxygen Concentrations

Abstract Generally, in water injection systems, oxygen levels starting from around eight ppm are deoxygenated to below 50 ppm, following international standards' guidelines. This work aims to discuss the impact of such a magnitude value of oxygen contamination on steel corrosion in seawater injection systems by analysing theoretical polarisation curves and results from published works with different approaches. Corrosion models consider mass-transfer controlled diffusion of oxygen to predict the maximum steel corrosion rate, which depends on the oxygen limiting current, which in turn is strongly influenced by flow velocity. The effect of free chlorine on corrosion in seawater injection systems has also been considered and included in an oxygen equivalent parameter. In such systems, where oxygen reduction is the key cathodic reaction, the corrosion process may be under cathodic activation control, independent of flow at higher velocities or when erosion-corrosion begins. In this work, theoretical polarisation curves were constructed by using published oxygen and chlorine cathodic limiting currents (iLc) on carbon steel and a noble metal electrode, respectively. Aerated (200 ppb and 9000 ppb of oxygen) and deaerated conditions (50 ppb of oxygen) and the presence of 300 ppb of chlorine were applied to the assumed exchange current densities (io). Neutral (pH 7) and acid (pH 4) conditions (considering the presence of CO2) were also assumed to be at room temperature and pressure. Since the corrosion rate in lower oxygen concentrations (ppb order of magnitude) may result in corrosion rates of the same order of magnitude than in higher oxygen concentrations (ppm order of magnitude) when comparing and analysing results from experimental, semi-empirical or mechanistic approaches, it is necessary to weigh up the effects of both steel surface (bare or scaled/corrosion products) and flow. At oxygen concentrations below 200 ppb and under acid conditions, the contribution of H+ reduction on corrosion rate starts to be higher than oxygen reduction, mainly in the absence of chlorine.

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