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Offshore Design & Installation
An Overview of Design, Analysis, Construction and Installation of Offshore Petroleum Platforms Suitable for Cyprus Oil/Gas Fields Summary of Offshore Construction Project stages Similar to the other fields of activities, the offshore platform construction services can be provided on a turn-key basis, i.e. covering inve...
Offshore Design & Installation
Environmental parameters The design and analysis of fixed offshore platforms may be conducted in accordance with the API’s “Recommended Practice for Planning, Designing, and Constructing Fixed Offshore Platforms – Working Stress Design (API-RP-2AWSD)”. The latest revision of API-RP-2A-WSD is the 21st edition dated Dece...
Offshore Design & Installation
Design of offshore fixed platforms The most commonly used offshore platforms in the Gulf of Mexico, Nigeria, California shorelines and the Persian Gulf are template type platforms made of steel, and used for oil/gas exploration and production (Sadeghi 1989, 2001). The design and analyses of these offshore structures mu...
Offshore Design & Installation
Different analyses needed for template platforms Different main analyses required for design of a template (jacket) type platform are as follows (Sadeghi 2001): • In-place analysis • Earthquake analysis • Fatigue analysis • Temporary analysis • Load out analysis • Transportation analysis • Appurtenances analysis • Lift...
Offshore Design & Installation
Structural analysis To perform a structural analysis of a platform, a structural model of the structure is developed normally using one of the following common software packages developed for the offshore engineering: SACS, FASTRUDL, MARCS, SESEM, OSCAR or StruCAD (Sadeghi 2001). A model of the structure should include...
Offshore Design & Installation
Any analysis of offshore platforms must also include the equipment weights and a maximum deck live loading (distributed area loading), dead loads in addition to the environmental loads mentioned above, and wind loads. Underwater, the analysis must also include marine growth as a natural means of enlargement of underwat...
Offshore Design & Installation
The platforms must be capable of withstanding the most severe design loads and also of surviving a design lifetime of fatigue loading. The fatigue analysis is developed with input from a wave scatter diagram and from the natural dynamic response of the platform, and the stiffness of the pile caps at the mudline by appl...
Offshore Design & Installation
Client permits and approval process All offshore platform designs (whether structural or facilities) must be approved by the Client. The analysis results must demonstrate that the platforms have been designed using standard accepted methods and that the structures will be able to perform adequately in accordance within...
Offshore Design & Installation
Fabrication (Construction) The API RP-2A lists the recommended material properties for structural steel plates, steel shapes and structural steel pipes. As a minimum, steel plates and structural shapes must conform to the American Society for Testing and Materials (ASTM) grade A36 (yield strength, 250 MPa) (AISC). For ...
Offshore Design & Installation
Load out and transportation The offshore structures are generally built onshore in “fabrication yards” for cost savings and to facilitate construction. Upon completion, these structures have to be loaded out and be transported offshore to the final assembly site, on board a vessel. Therefore an offshore design and anal...
Offshore Design & Installation
Installation All the structural sections of an offshore platform must also be designed to withstand the lifting/launching, upending, uprighting and other installation stresses. The jackets must be designed to be self-supporting during the pile driving and installation period. Mudmats are used at the bottom horizontal b...
Oil & Gas Projects Australia
Construction of the Darwin Liquefied Natural Gas (LNG) plant began in June 2003 and the plant was commissioned in the first quarter 2006 when LNG sales commenced. The Darwin LNG facility has a single tank for LNG storage and is one of the largest above-ground LNG tanks constructed to date with a working capacity of 188...
Oil & Gas Projects Australia
The Field, which is 100% owned and operated by Eni, will deliver gas to the Northern Territory’s Power Water Corporation (PWC) for over a period of 25 years, with supply rising to 18,000 boe/day over the life of the contract. Approximate value: $500 million Construction started: 2006 First production: 2009 ICN Involv...
Oil & Gas Projects Australia
Discovered in 1995, the Bayu-Undan field plays a vital role in ConocoPhillips’ Australian operations. Bayu-Undan is a gas-condensate field located offshore in the Timor Sea within the Joint Petroleum Development Area (JPDA). The field is 250 kilometres south west of Suai in Timor-Leste and 500 kilometres north west of ...
Oil & Gas Projects Australia
Karratha gas plant. In 2008, the facility capacity was increased to 16.3 million tonnes per year with the commissioning of a fifth, 4.4 million tonnes per year LNG production train. As well as processing gas for export, the facility supplies domestic supplies to consumers and businesses in Western Australia. The facil...
Oil & Gas Projects Australia
Karratha expansion In April 2007 Woodside Energy announced their phase V expansion at the Karratha gas plant, which included the addition of a fifth liquefaction train (4.4 million tons per annum) and also other infrastructure including: acid gas recovery unit, the third fractionation unit for the site, train five jett...
Oil & Gas Projects Australia
Ichthys Offshore Integrated Project Management Support Services (IPMS) Client Ichthys Joint Venture Location Offshore Darwin, Northern Territory JV Clough Doris Scope of Work Integrated Project Management Services overseeing the detailed design, procurement, fabrication, commissioning, tow to site, and offshore hook-u...
Oil Gas Commissioing & Startup Challenges
The Pluto gas field was discovered in early 2005 in the North West Shelf area, approximately 180 km from the Burrup Peninsula and 100 km from the northern coast of Western Australia. Pluto LNG comprises an onshore processing plant on the Burrup Peninsula and associated LNG and condensate storage and export facilities. ...
Oil Gas Commissioing & Startup Challenges
Pluto LNG processes gas from the Pluto gas field, located in the Carnarvon Basin about 190 km north-west of Karratha, in north-west Western Australia. It is 90% owned and operated by Woodside with the remaining 10% owned in equal share by Tokyo Gas and Kansai Electric. The Pluto field was discovered in 2005. The Greate...
Oil Gas Commissioing & Startup Challenges
This paper describes the innovative methods used to tackle these challenges and describes the processes taken to ensure the start-up was a success. This paper describes a number of the technical challenges associated with the Pluto LNG start-up and the solution methods adopted by Woodside to overcome or deal with thes...
Oil Gas Commissioing & Startup Challenges
Facilities Description The initial phase of Pluto LNG comprises an offshore platform in 85m of water, connected to five subsea wells on the Pluto gas field in 800m of water. Offshore MEG (mono-ethylene glycol) injection is used to prevent subsea hydrate formation. Gas, condensate and MEG flow from the subsea wells to a...
Oil Gas Commissioing & Startup Challenges
Start-Up Organisation Construction and commissioning of the onshore facilities to the point of hydrocarbon introduction was managed by the onshore managing contractor, a Foster-Wheeler Worley Parsons Joint Venture. The start-up of the facility was carried out on an area basis. At the time of hydrocarbon introduction co...
Oil Gas Commissioing & Startup Challenges
Start-Up Logic The high level Pluto LNG start-up logic is shown in figure 3. Initial commissioning was restricted to the diesel generation equipment and essential utilities (instrument air, flare system, nitrogen, and fire water) with the aim of preparing the plant for introduction of domestic gas. The introduction of ...
Oil Gas Commissioing & Startup Challenges
Use of Domestic Gas for Commissioning Purposes The Pluto LNG Park is located adjacent to a domestic gas pipeline. A tie-in to this pipeline was made during the construction of the facility which allowed the use of domestic gas for initial commissioning of the flare and fuel gas systems, power generation facilities, ref...
Oil Gas Commissioing & Startup Challenges
Impact of Flare Tower Replacement It was identified during the project construction phase that the main Pluto LNG flare tower required replacement as it was not adequately designed for the high wind loading that occurs during cyclonic conditions at the Pluto LNG site. This issue had the potential to cause significant d...
Oil Gas Commissioing & Startup Challenges
MEG & ETP Commissioning The onshore MEG system and the effluent treatment plant (ETP) posed a significant start-up challenge as they are complex process units which are not widely used in the LNG industry. Start-up of both the MEG and ETP were carried out early to ensure the maximum reliability of the units during the ...
Oil Gas Commissioing & Startup Challenges
MEG start-up A first fill of MEG was shipped to the onshore system approximately 12 months before the commencement of the LNG train start-up. The volume of MEG imported was 9,000 m3. The MEG was imported via chemical tanker which berthed at the Pluto LNG offtake jetty. The MEG was discharged from the tanker and routed ...
Oil Gas Commissioing & Startup Challenges
Effluent treatment plant start-up The Pluto LNG effluent treatment plant contains a biological treatment facility for removal of MEG from the produced water. This bioreactor has limited capacity to remove hydrocarbons and so the ETP also contains corrugated plate interceptors and a macro-porous polymer extraction (MPPE...
Oil Gas Commissioing & Startup Challenges
Storage and Loading Cool-Down Cool-down of the Pluto LNG storage and loading facilities was performed in advance of the LNG train start-up using cold gas and LNG supplied from an externally sourced LNG cargo. The procedures for the LNG import and tank cool-down were developed using best practice techniques gathered fro...
Oil Gas Commissioing & Startup Challenges
Propane A first fill of refrigerant grade liquid propane was supplied via trucks from Perth, a distance of approximately 1600 km by road. The volume of propane delivered was sufficient to fill both the propane circuit and meet the initial propane fill requirements of the mixed refrigerant circuit. The propane was suppl...
Oil Gas Commissioing & Startup Challenges
Ethane Mixed refrigerant for the Pluto LNG start-up was generated using the “Once through MR” process. This process leverages from Woodside’s operational experience of managing small internal leaks within the LNG train main cryogenic heat exchangers (MCHEs) and involves bleeding natural gas into the mixed refrigerant (...
Oil Gas Commissioing & Startup Challenges
Commissioning and Start-Up of Offshore Facilities Approximately 12 months prior to the LNG train start-up the offshore system was pressurised with natural gas taken from the domestic gas pipeline that runs close to the Pluto LNG facilities. Pressurisation of the trunkline and flowlines was required to provide sufficien...
Oil Gas Commissioing & Startup Challenges
Flow assurance issues during first start-up Wel stream gas was introduced to the onshore facilities once the onshore gas pre-treatment facilities were ready for start-up. The flow of gas to shore was initially at relatively low rates, as dictated by onshore fuel gas and commissioning requirements with offshore trunklin...
Oil Gas Commissioing & Startup Challenges
Ramp up of wells during LNG train start-up Well ramp up rates were restricted during early operation to allow the wells to stabilise and minimise the risk of formation damage and sand production. During final cool-down and ramp-up of the LNG train there is a very rapid increase in natural gas flow which is faster than ...
Oil Gas Commissioing & Startup Challenges
Nitrogen Rejection Unit The nitrogen rejection unit (NRU) is designed to remove nitrogen from the Pluto LNG end-flash gas. This is necessary to allow the end-flash gas to be burnt in the fuel gas system. The start-up of the NRU requires end-flash gas from the LNG train and thus cannot be commenced until after the LNG t...
Oil Gas Commissioing & Startup Challenges
Cool-down of the NRU is a lengthy process with a cool-down and ramp-up from ambient conditions taking several days. Process conditions change very slowly which means changes made to flows or pressures may not impact the cool-down until several hours later. This means the start-up operation spans several shifts and it i...
Oil Gas Commissioing & Startup Challenges
Storage and loading flare The flares at the Pluto LNG facility were designed to minimise dark smoke during plant production. In order to meet this requirement the Pluto LNG storage and loading flare was provided with air-assist technology, which reduces smoke formation by using air blowers to force mixing of air and hy...
Oil Gas Commissioing & Startup Challenges
Ramp-Up Performance The culmination of the described start-up techniques was a safe, reliable and successful start-up of the Pluto LNG facilities. Figure 6 shows the capacity and reliability performance of the Pluto LNG facilities over the first few months of operation. The train achieved production rates close to desi...
Oil Gas Commissioing & Startup Challenges
The start-up of the Pluto LNG facilities is considered to be a great success, with a rapid ramp-up and high reliability over the initial operational period. This is considered testament to the level of planning and preparation, the high quality team and the innovative start-up methodologies which were employed. The sta...
Oil Tanker & Ship Building
Ships are large, complex vehicles which must be self-sustaining in their environment for long periods with a high degree of reliability. The naval architect is concerned with the hull, its construction, form, habitability and ability to endure its environment. The navigating officer is responsible for safe navigation o...
Oil Tanker & Ship Building
Many modern cargo and passenger liners have a transverse propulsion unit or bow thruster in the bows. Its purpose is to give greater manoeuvrability in confined waters, e.g. ports, and so reduce or eliminate the need for tugs. The modern tendency is to have large unobstructed holds with mechanically operated hatch cove...
Oil Tanker & Ship Building
A ship's actual design and number of decks depend on the trade in which the ship will ply. A tramp, carrying shipments of coal or ore, will be a single deck vessel with large unobstructed hatches to facilitate loading and discharge. A cargo liner carrying a variety of cargo in relatively small consignments would have '...
Oil Tanker & Ship Building
Three principal types of machinery installation are to be found at sea today. The three layouts involve the ship’s propulsion machinery using direct-coupled slow-speed diesel engines (the main engine), medium-speed diesels with a gearbox, and the steam turbine with a gearbox drive to the propeller. The propeller shaft...
Oil Tanker & Ship Building
COW Lines (Crude Oil Washing) On the main deck you will find the cow main line with branches leading to the ships crude oil washing machines. This line comes from the cow cross over line on the delivery side in the pump room.
Oil Tanker & Ship Building
Inert Lines To control the atmosphere in the cargo tanks you will find inert lines on the main deck leading to each tank. These lines are for supplying inert gas during discharging or tank washing. Some inert gas systems are connected to a main riser, which are fitted with a press/vacuum valve for regulation of the pre...
Oil Tanker & Ship Building
Cargo heating In addition to the provision of cargo compartments, pipelines and pumps for handling the oil, the oil tanker must also provide adequate heating systems for some types of oil and cooling systems for others. Properly constructed ventilation systems are necessary in all oil tankers in order to avoid excessiv...
Oil Tanker & Ship Building
Ventilation Cargo pump rooms shall be mechanically ventilated and discharges from the exhaust fans shall be led to a safe place on the open deck. The ventilation of these rooms shall have sufficient capacity to minimize the possibility of accumulation of flammable vapours.
Oil Tanker & Ship Building
Gas freeing It is generally recognized that tank cleaning and gas freeing is the most hazardous period of tanker operations. This is true whether washing for clean ballast, gas freeing for entry, or gas freeing for hot work.
Oil Tanker & Ship Building
Oil Tankers Based on size, oil tankers have been categorised into the following types: 1.Small Range (Product) Tanker: 10,000 to 60,000 tons DWT. 2.Panamax Tanker: 60,000 to 78,000 tons DWT. 3.Aframax (Average Freight Rate Assessment) Tanker: 80,000 to 1,20,000 tons DWT. 4.Suezmax Tanker: 1,20,000 to 2,00,000 tons DWT....
Oil Tanker & Ship Building
The most important design drawing that is to be studied in order to identify the design of a ship, is its General Arrangement Drawing. Figure 3 illustrates the profile view of an oil tanker’s general arrangement. It basically shows the arrangement of all the spaces within the ship, and gives a frame-by-frame location o...
Oil Tanker & Ship Building
Bulbous Bow: Today, all tankers are equipped with a bulbous bow, so as to increase the power efficiency of the ship. Though these are slow speed ships, a bulbous bow reduces the wave making resistance considerably.
Oil Tanker & Ship Building
Structural Design: The structural design of oil tankers vary according to the type and size of the tanker. To understand them, we will study their midship sections in detail.
Oil Tanker & Ship Building
Double Hull Tankers: All oil tankers of length above 120 m are required to be double hulled, as per MARPOL rules. Panamax, Aframax, Suezmax, VLCC and ULCC tankers are all double-hulled. The primary reason for providing two hulls is to prevent the contact of cargo oil with the external environment in case of any structu...
Oil Tanker & Ship Building
Power and Propulsion: Since tankers are low speed vessels (average maximum cruising speed is 15.5 knots), and are not restricted by space constraints, they can afford to be run by large slow speed marine diesel engines. These engines occupy more space than high speed marine diesel engines, but provided more shaft effic...
Oil Tanker & Ship Building
Systems On-board: Oil tankers have a number of systems that are unique to its operation. We will discuss the most important ones in brief. •Cargo Oil Heating System: Ships carrying crude oil are equipped with this system, as crude oil is heavy and becomes very sluggish and thick in cold environments, which can block t...