Single Buoy Mooring Research Articles

Analisa Keselamatan dan Kesehatan Kerja pada Proses Pemuatan Crude Oil di Single Buoy Mooring Tuban Marine Terminal

Single Buoy Mooring (SBM) is a means for mooring tankers to carry out loading or unloading operations through SBM located on the high seas. SBM serves to facilitate loading or unloading crude oil by connecting the installation on land through pipes connected to the SBM system on the high seas. The thing that is considered so that the mooring process runs safely is by minimizing the factors and hazards that cause the mooring process to be hampered. the danger at the time of loading at SBM is during the process of mooring the ship and the danger of H2S gas contained in curde oil. During the loading of crude oil, the cargo must always be checked for H2S gas levels in crude oil, this gas is quite dangerous when exposed directly to H2S gas. It can cause loss of smell, eye irritation, shortness of breath, unconsciousness and death. This thesis research method is a qualitative descriptive method by analyzing the problem using Hazard Identification, Risk Assessment, Risk Control (HIRARC).

Case Studies: Application of Oil Spill Response Good Practice Guides for Inland and Near-shore Operations

Following key oil spill incidents in the Gulf of Mexico and Australia, the industry initiated a three-year Joint Industry Project to develop guidelines for oil spill preparedness and response management. These documents are commonly known as the Oil Spill Response JIP (OSR-JIP) Good Practice Guides. As the OSR-JIP originated from lessons learnt from offshore incidents, it is only natural that the industry would apply it with the same type of operation, hence the tendency to limit the practical application for inland or near-shore facilities. This paper presents two examples where the OSR-JIP guides are applied at downstream operations located inland and near-shore. The first study is on a refinery located near-shore with an operational jetty and a single buoy mooring. We started with a comprehensive review of their operations and updated their oil spill risk assessment profile in line with the framework described in the OSR-JIP Tiered Preparedness and Response. This process provided a reflection of their current capability and identified the gaps for further improvement. Following this, we proceeded to update the contingency plan using the OSR-JIP Contingency Planning to ensure that the risks identified are adequately mitigated with training of personnel and equipment selection. This exercise supported in improving the readiness of the facility to respond to oil spill incidents in future. The second study involves a terminal located inland that supplies refined products through a pipeline that leads towards a jetty on the coast. We developed several area specific tactical response plans that cover risks from their above-ground pipelines and at the jetty where loading and offloading of the products to tankers are conducted. To accurately define the suitable response technique, we started the planning process with an oil spill risk assessment following OSR-JIP Risk Assessment. The tactical response plans were then developed with reference to several other OSR-JIP guides such as OSR-JIP Inland Response and NEBA. The resulting plans describe health and safety concerns, identification of sensitive receptors, response techniques, location and quantity of resources, logistical requirements and timings and waste management. Based on these case studies, we demonstrated that the OSR-JIP guides can certainly be applied for inland and near-shore facilities and have a more far wider application for the whole oil and gas industry rather than be limited to offshore operations.

Study of heavy metal levels in seawater in the vicinity of Single Buoy Moorings at Mina Al Fahal, Sultanate of Oman

ABSTRACTThis study was conducted to determine the concentrations of cadmium, copper, lead, and vanadium in seawater samples taken from the vicinity of Single Buoy Mooring 3 (SBM3) at Mina Al Fahal in the Sultanate of Oman. SBM3 is one of three locations at Mina Al Fahal (SBM1 and SBM2) associated with importing and exporting refined petroleum products. Using graphite furnace atomic absorption spectrophotometry, concentrations of these four metals in seawater samples were measured in six samples. None of the metals was present in concentrations greater than the European Commission/United Kingdom Environmental Quality Standards, but a comparison to previous data collected at SBM2 indicates that concentrations have increased approximately 40% over the past two decades. To better identify sources of the metals, it is imperative to monitor effluents and collect more targeted samples at and/or near discharge points.

Analysis and simulation of a single buoy mooring system based on sea environment

Single Point Mooring (SPM) is of great use to offshore floating structures which are currently in use in Vietnam’s coastal waters. However, this country is facing the lack of the related guidelines and standards for analysis, simulation and design of SPM system. This fact is the rationale for this paper which is aimed to propose a procedure for computation of the effects of sea environment on a SPM system. Specifically, the procedure enables the identification of maximum load exerting on the mooring buoy. Then, such identification together with the water depth parameter enables the determination of the optimal length and diameter of the desired chain. Finally, this paper presents a primary simulation of the mooring chain system according to various water depth conditions.

Using Grouper Fish as Bio-indicator of Cd, Cu, Pb and V in the Vicinity of a Single Buoy Mooring (SBM3) at Mina Al Fahal in the Sultanate of Oman

This paper investigated metal contamination in muscle tissue of the grouper (Epinephelus coioides) in the vicinity of a single buoy mooring (SBM3) at the Sultanate of Oman. The fish samples were analyzed for cadmium (Cd), copper (Cu), lead (Pb) and vanadium (V). The mean concentrations of Cd, Cu, Pb and V in the fish samples were 0.05±0.004, 0.34±0.013, 0.20±0.018 and 0.03±0.006mg/kg, respectively. The results were compared with the corresponding permissible concentration limits according to the Sultanate of Oman (0.05, 3.28, 0.3 and 1.4mg/kg for Cd, Cu, Pb and V, respectively) and the European Commission (0.05mg/kg for Cd and 0.3mg/kg for Pb). It was found that none of the overall mean metal concentrations exceeded the corresponding Omani legislation or European Commission limits. However, the overall mean concentration of Cd was identical to the maximum permissible limit of 0.05mg/kg that has been established by both Commissions, and the limits were exceeded for mean Cd levels in fish at two of the six sampling stations at SBM3. In general, this study indicated that the fishes at SBM3 were not highly contaminated with these metals.

Continuous‐time modeling and global optimization approach for scheduling of crude oil operations

AbstractScheduling of crude oil operations is a critical and complicated component of overall refinery operations, because crude oil costs account for about 80% of the refinery turnover. Moreover, blending with less expensive crudes can significantly increase profit margins. The mathematical modeling of blending different crudes in storage tanks results in many bilinear terms, which transforms the problem into a challenging, nonconvex, and mixed‐integer nonlinear programming (MINLP) optimization model. Two primary contributions have been made. First, the authors developed a novel unit‐specific event‐based continuous‐time MINLP formulation for this problem. Then they incorporated realistic operational features such as single buoy mooring (SBM), multiple jetties, multiparcel vessels, single‐parcel vessels, crude blending, brine settling, crude segregation, and multiple tanks feeding one crude distillation unit at one time and vice versa. In addition, 15 important volume‐based or weight‐based crude property indices are also considered. Second, they exploited recent advances in piecewise‐linear underestimation of bilinear terms within a branch‐and‐bound algorithm to globally optimize the MINLP problem. It is shown that the continuous‐time model results in substantially fewer bilinear terms. Several examples taken from the work of Li et al. are used to illustrate that (1) better solutions are obtained and (2) ε‐global optimality can be attained using the proposed branch‐and‐bound global optimization algorithm with piecewise‐linear underestimations of the bilinear terms. © 2011 American Institute of Chemical Engineers AIChE J, 2012

Novel solution approach for optimizing crude oil operations

AbstractScheduling of crude oil operations is a complex nonlinear problem, especially when tanks hold crude mixes. We present a new mixed‐integer nonlinear programming (MINLP) formulation and a novel, mixed‐integer linear programming (MILP)–based solution approach for optimizing crude oil unloading, storage, and processing operations in a multi‐CDU (crude distillation unit) refinery receiving crude from multiparcel VLCCs (very large crude carriers) through a high‐volume, single‐buoy mooring (SBM) pipeline and/or single‐parcel tankers through multiple jetties. Mimicking a continuous‐time formulation, our primarily discrete‐time model allows multiple sequential crude transfers to occur within a time slot. It incorporates several real‐life operational features including brine settling and tank‐to‐tank transfers, and is superior to other reported models. Notably our algorithm avoids concentration discrepancy and MINLP solutions by identifying a part of the horizon, for which its linear relaxation is exact, and then solving this MILP repeatedly with progressively shorter horizons. By using 8 h time slots and a hybrid time representation, an attractive approach to this difficult problem is presented.© 2004 American Institute of Chemical Engineers AIChE J, 50:1177–1197, 2004

A new continuous-time formulation for scheduling crude oil operations

In today's competitive business climate characterized by uncertain oil markets, responding effectively and speedily to market forces, while maintaining reliable operations, is crucial to a refinery's bottom line. Optimal crude oil scheduling enables cost reduction by using cheaper crudes intelligently, minimizing crude changeovers, and avoiding ship demurrage. So far, only discrete-time formulations have stood up to the challenge of this important, nonlinear problem. A continuous-time formulation would portend numerous advantages, however, existing work in this area has just begun to scratch the surface. In this paper, we present the first complete continuous-time mixed integer linear programming (MILP) formulation for the short-term scheduling of operations in a refinery that receives crude from very large crude carriers via a high-volume single buoy mooring pipeline. This novel formulation accounts for real-world operational practices. We use an iterative algorithm to eliminate the crude composition discrepancy that has proven to be the Achilles heel for existing formulations. While it does not guarantee global optimality, the algorithm needs only MILP solutions and obtains excellent maximum-profit schedules for industrial problems with up to 7 days of scheduling horizon. We also report the first comparison of discrete- vs. continuous-time formulations for this complex problem.

Solving A Harbour Sedimentation Problem In Yemen

The Ash Shihr, Yemen harbour on the Gulf of Aden was built in 1992193 by Nexen Inc. for the vessel fleet supporting the loading of oil into large tankers at the offshore Single Buoy Mooring (SBM). In designing the harbour, the greatest emphasis was placed on ensuring that the harbour provided effective shelter during the SW summer monsoon season, which can generate deep water waves of up to about 6.4 m significant wave height with a period of 14 seconds. This led to the harbour entrance being placed on the east side of the harbour to minimize wave agitation within the harbour. The dominant factor proved to be the littoral drift of sediment in a westerly direction. This led to the migration of large amounts of sediment into the harbour and the build up of sand on the beach well to the east of the harbour. As this situation developed it was effectively closing the harbour. A sedimentation study of the harbour was performed by Delft Hydraulics [l]. Various solutions were considered including by-pass maintenance dredging, a dredged sand trap, relocating the harbour entrance, and shielding the harbour with a sand trap breakwater. Westmar Consultants Inc. provided the detailed design for a 600 metre long sand trap breakwater which resulted in economically viable construction bids. The work was successfully completed by Yemen based contractors in May 2001. The quality of the work is excellent and the breakwater is performing as designed in trapping sand and preventing the longshore drift from accreting in the entrance. Transactions on the Built Environment vol 58 © 2001 WIT Press, www.witpress.com, ISSN 1743-3509

The Kittiwake Field, Block 21/18, UK North Sea

Abstract Kittiwake was discovered by well 21/18-2 within a 7th Round block, part of Production Licence P351. Highly undersaturated oil is present in the Fulmar Formation and Skagerrak Formation reservoir sequences; 70 MMBBL of reserves is in Fulmar sandstones whereas oil in the Skagerrak is mostly immovable. The field will be developed from a single 16-slot platform with initially 5 producing and 5 water-injection wells. Solution gas is removed via the Fulmar Field pipeline to St Fergus and, as from September 1990, the oil is loaded onto tankers from a single-buoy mooring.

Preliminary Design of a 1-MWe OTEC Test Plant

An ocean-based, 1-MWe (gross) test plant has been planned to establish the feasibility of OTEC (ocean thermal energy conversion) power generation in the revised Sunshine Project. The preliminary design of the proposed test plant employs a closed-cycle power system using ammonia as the working fluid on a barge-type platform with a rigid-arm-type, detachable, single-buoy mooring system. Two types each of titanium evaporators and condensers are to be included. The steel, cold-water pipe is suspended from the buoy. The design value of the ocean temperature difference is 20 K. The paper presents an overview of the preliminary design of the test plant and the tests to be conducted.

Study of Flow Improvers for Transportation of Bombay High Crude Oil Through Submarine Pipelines

Summary During pumping of waxy crude oil through longdistance pipelines, crystallization of wax can cause serious problems. If the pipeline is shut down, the wax may gel the cooling crude and block the pipeline. Studies were made of several flow improvers and waxy crudes, and a bench-scale laboratory test unit was developed for evaluating such crudes. The test rig accurately simulates cooling conditions in the pipeline and satisfactorily predicts ability to restart flow of a particular crude. predicts ability to restart flow of a particular crude. Introduction In March 1974 the Oil and Natural Gas Commission (ONGC) of India discovered the Bombay High offshore oil field 160 km west-northwest of Bombay (Fig. 1). The field's oil-bearing zone has an area of about 700 km. The average water depth is about 700 m, and the vertical depth of the main limestone pay zone (L III) is 1350 m. After a number of wells were drilled to delineate the field, production of crude oil was started on May 21, 1976, through a well-cum-production platform. Initial production was about 4,300 B/D, platform. Initial production was about 4,300 B/D, and this gradually was raised to 80,000 B/D. During the initial phase of production, oil was stored in the tanker Jawaharlal Nehru anchored in the field to a single-buoy mooring. Crude oil from this tanker was dispatched to coastal refineries by means of daughter tankers, but in view of the production potential of the field, a 30-in.-diameter, production potential of the field, a 30-in.-diameter, 203-km-long submarine pipeline was laid to connect the field to the onshore terminal at Uran. Pumping of the offshore crude though this submarine line started on June 13, 1978, from Platform F. From the Uran terminal, the crude oil is transported further through feeder pipelines to refineries and to a tanker loading terminal at Butcher Island near Bombay.Bombay High crude oil is waxy, and it has a pour point on the order of 30 degrees C (Table 1). Pipeline point on the order of 30 degrees C (Table 1). Pipeline transportation through the submarine section was expected to pose problems because the average minimum seabed temperature in this region ranges from 22 to 24 degrees C, with a lowest recorded temperature of 20 degrees C. Therefore, after an emergency shutdown of the pipeline, gelling of the crude oil could make restarting difficult, if not impossible, after only a few days of cooling. Various measures were considered to keep the crude oil in an acceptable state of fluidity, even at the lowest seabed temperature. These included (1) dilution with less waxy crude, (2) crude oil conditioning, and (3) treatment with flow improvers.The dilution method was not possible because a less waxy crude oil is not available near the Bombay High field. Crude oil conditioning by proper heat treatment can improve the fluidity of some crude oils, as demonstrated in Assam, East India, but this would require a huge treatment plant on one of the offshore platforms at the field. Running costs such as energy and manpower are very high, so this was clearly not a viable approach. The response of Bombay High crude oil to such a conditioning procedure also would require evaluation. procedure also would require evaluation. The oilfield operators (ONGC), therefore, decided to use an additive treatment, and screening work was started with a large number of commercially available additives to assess their effect on the pour point of Bombay High crude oil. Only a few point of Bombay High crude oil. Only a few additives showed any significant effect, and these were tested further by ONGC to determine yield stress and plastic viscosity improvement. From the results of plastic viscosity improvement. From the results of this study, one additive (A) finally was selected for continuous use in the Bombay High crude oil submarine pipeline. JPT P. 2539

The Programmed Traverse Light

Due to the very low power-to-weight ratio found in large deadweight ships, their high inertial values and the very long reaction time to manoeuvring commands, difficulties often arise in achieving entry to the berthing area at an exactly pre-determined speed over the ground.This paper describes a dynamically programmed optical aid to help the navigator achieve exactly the prescribed speed over the ground as he decelerates along his traverse or intended track when approaching his terminal or swinging area. The authors are consultants to AGA Navigation Aids Ltd who have developed this device.Over the last decade or more, some very significant changes have occurred in the general requirements relating to the handling and manoeuvring of certain classes of modern vessel in the approach to their terminal berth – whether jetty, single-buoy mooring or even when coming to anchor. The economy of size in the bulk trades has probably had the most profound effect. This often reduces the power/weight ratio of the vessel itself to a very low order. In turn this has led to radical adjustments in techniques of ship handling in the final approach phases, due to the long response time between command instructions and reactions to these by the vessel itself. When considering the inertia of a vessel of 220000 tons deadweight or more – where the feasible deceleration or rate of change of speed is also of a low order – we can see the difficulties met with when endeavouring to enter the berthing area at an exactly required pre-determined speed over the ground (as opposed to speed through the water) often as low as one tenth of a knot or less.

強風下における1点ブイ係留船の港内避泊に関する模型実験

In order to investigate on a single buoy-mooring in harbour under heavy weather, this paper provides analytical approaches in the prediction of relation between the mooring force and yaw-motion of a ship excited by strong wind, and also discusses practical methods to reduce the force and the yaw-motion. The experimental results of 1:50 scale model cargo ship 5, 000 GT class were used to check the calculated results of computor simulation on these problems. And the model tests in wind and current carried out by making use of both the wind generator tank and the circulating water tank at our laboratory.

Anglesey Pipeline Project

The paper briefly describes a major project, recently completed by Shell UK Oil, comprising a single-buoy mooring facility, with storage and pumping installations at Amlwch on the north coast of Anglesey with a 127 km-long connecting pipeline to feed crude oil to its Stanlow refinery on Merseyside. The power installations are briefly described, together with other environmental aspects which influenced the design. These included the installation of pumps and motors ranging in size from 500 kW to 3280 kW, so that they did not exceed a permitted noise level of 29 dBA under full-load conditions; designing a lighting scheme which would not draw undue attention at night to a large storage and pumping complex which by day is well camouflaged by the geography of the land; providing adequate earthing at installations built on rock and ensuring the correct functioning of control equipment on a network subject to frequent lightning storms. The ways in which these and other problems were overcome are described.

Low-Frequency Phenomena Associated With Vessels Moored at Sea

Abstract The influence of the low-frequency-wave-drifting force on the motions of moored vessels and the loads in the mooring system is demonstrated from results of model tests in irregular waves. The origin of the wave drifting force is discussed and methods for calculating the mean drifting force are reviewed. To facilitate calculation of the low-frequency-wave drifting force on an object in irregular waves, an existing method using the mean drifting force in regular waves is generalized. The results of calculations using the method introduced in this paper are compared with previously published test results. Finally, some remarks are added concerning effects that have not been accounted for in existing calculation methods. Introduction A vessel moored at sea in stationary conditions with regard to waves, wind, and current is subjected to forces that tend to shift it from the desired position. For a given vessel and position in the position. For a given vessel and position in the horizontal plane, the motions depend on both the mooring system and the external forces acting on the vessel. In steady conditions, the forces caused by a constant wind and current are constant quantities for a given heading angle of the vessel. The forces caused by a stationary irregular sea are of an irregular nature and may be split into two parts: first-order oscillatory forces with wave parts: first-order oscillatory forces with wave frequency, and second-order, slowly varying forces with frequencies much lower than the wave frequency.The first-order oscillatory wave forces on a vessel cause the well known ship motions whose frequencies equal the frequencies present in the spectrum of the irregular waves. These are the linear motions of surge, sway, and heave and the three angular motions of roll, pitch, and yaw. In general, the first-order wave forces are proportional to the wave height, as are the ensuing motions. The magnitude of the linear oscillatory motions is in the order of the height of the waves.The second-order wave forces, perhaps better known as the wave drifting forces, have been shown to be proportional to the square of the wave height. These forces, though small in magnitude, are the cause of the low-frequency, large-amplitude, horizontal motions sometimes observed in large vessels moored in irregular waves. Tests run in irregular waves in wave tanks of the Netherlands Ship Model Basin revealed a number of properties and effects of the low-frequency-wave properties and effects of the low-frequency-wave drifting force that are discussed here using the results of two test programs.The first of these programs concerns tests run with the model of a 125,000-cu m LNG carrier moored in head seas with an ideal linear mooring system. The second program deals with a 300,000-DWT VLCC moored with a realistic nonlinear bow hawser to a single-buoy mooring in waves, wind, and current coming from different directions.The results of the tests with the LNG carrier are shown in Figs. 1 through 3, while the results of the tests with the 300,000-DWT VLCC are shown in Fig. 4. All results are given in full-scale values. Fig. 1 shows the wave trace and the surge motion of the LNG carrier to a base of time. SPEJ P. 487

Design Criteria for Single-Point Mooring Terminals

Single-point moorings (SPMs) have come to be accepted as a logical choice for offshore berths for large tankers. The type most commonly used is that in which a single-buoy mooring (SBM) is anchored to the seabed with long catenaries of chain. Site selection for SPMs is governed above all by safety of operation of the tanker in maneuvering and mooring. Site conditions and marine environment play a major part in judging this safety. Detailed information is required on bottom conditions, sea levels, currents, winds, waves, and visibility. In the design of a specific SBM system, the main parameter is the mooring load. Determination of this load requires model tests, since reliable design formulas are not yet available. SBM can be operated without causing pollution to the surrounding coastline and without detrimental effect on the local marine environment.

Hydraulic Trenching of Submarine Pipeline

A consortium of oil companies commissioned two firms of contractors to construct, as a joint venture, a single buoy mooring system off the South African coast. It was planned to pull the pipes out to the sea through a sleeve to be placed in a trench blasted 600-ft rocky reef in the surf zone, and to bury the pipe on the seaward side of the reed between chainages 1,705 and 8,000. The note describes the design of trenching device, the hydraulic trials, and the operation.