Offshore Mechanics and Arctic Engineeri ng - Gesellschaft für ...

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were washed down the rivers <strong>and</strong> streams (Oranje, Vaal, Buffels, etc.) to the Atlantic together with vast soil masses. At first, the diamonds settled in the river mouths, but they were then distributed in the sea over wide areas by the Benguela current flowing along the west coast of southern Africa. Originally, diamond mining was practiced in the strips of l<strong>and</strong> near the coast. lt was only in the sixties of the last century that the Atlantic in proximity to the coast was explored for diamonds <strong>and</strong> deposits worth mining were discovered. The diamonds were initially recovered by divers in the shallows. But this method was not an economic investment for a large-scale enterprise. ln 1990, Wirth was therefore awarded an order to develop a large-diameter drilling system to loosen Wirth PBA the diamond-containing 933 on hook being prepared for operation on the st<strong>and</strong> pipe overburden on the seabed <strong>and</strong> to crush from the magazine to the borehole center bed above. The entire system is operated <strong>and</strong> convey the soil up to the mining ves- for installation <strong>and</strong>, in the opposite direc- fully hydraulically, <strong>and</strong> controlled <strong>and</strong> mosel. Right from the start, this system protion, for removal. The large-diameter rock nitored by a computer system. The mining ved to be very efficient <strong>and</strong> economic. bit of approximately 7 m drilling diameter is vessel can operate up to a maximum water In the meantime, the customer De Beers deposited on the main deck below the drill depth of 200 m. has acquired a complete fleet of diamond mining vessels from Wirth, which perma- deck (see picture). A second large-diameter rock bit is available as reserve on the mining Diamond sampling nently are in operation. vessel. Before starting diamond mining, the sea- Mining vessel In front of the derrick front, a tower-type receiving bin is installed to take the materibottom is explored for its diamond contents. Wirth has also developed a system The mining vessels are configured with al transported to the surface, including the for this sampling. The samples are drilled by a midship moon pool through which the flushing water. From this bin, the material is a machine operating completely under wa- large-diameter rock bit can be lowered. transported to the separation plant mounted ter without a drill pipe <strong>and</strong> are transported lnstalled just above the moon pool center on the bow, where the entire material is tre- to the ship through a hose line, using the is the derrick fitted with the drilling equipated until, finally, only the diamonds are left. air-lift system. ment. A heave compensator system ensu- The operation mode of mining vessels is as The machine is capable of drilling explores that the drill bit remains on the borehole follows: ralory holes up to about 2 m in diameter, bottom, at almost constant thrust, even in Four anchor winches position the mining with a max. depth of 8 m, in the seabed. case of high seas <strong>and</strong>, consequently, high vessel exactly above the desired drilling Just like the diamond mining equipment, vertical ship movement. A twin-type cardan point. After the large-diameter rock bit this system can also operate up to a depth joint system is provided against buckling of with the drill pipe has been installed, <strong>and</strong> of 2OO m. All movements <strong>and</strong> functions the drill string in case of large roll <strong>and</strong> pitch the drill bit touches the seabed, the hea- are remote-controlled <strong>and</strong> monitored from movements. ve compensator system, the rotary swivel the deck of its escort ship. The complete lnstalled at the rear of the derrick, is a verti- drive <strong>and</strong> the air-lift system are started up. hydraulic drive system <strong>and</strong> the electronic cal magazine for the air-lift flange drill pipe. The large-diameter rock bit excavates the control system are installed underwater A special loader transports the drill pipe material, which is conveyed up the drill on the drilling rig. Energy <strong>and</strong> the control ''t'F i* L * .' t*-l.il pipe into the towertype receiving bin. After the borehole has been drilled comm<strong>and</strong>s are supplied <strong>and</strong> given through an umbilical. The drilling samples are conveyed to the escort ship on the surface through a discharge hose. down to a previously Thanks to the wide range of applications defined depth, the <strong>and</strong> the many years spent developing our drill bit is lifted until products, Wirth is the worldwide leader in !4l7 it hangs some meters this domain <strong>and</strong> is looking forward to ex- above the seabed. p<strong>and</strong>ing this position in the future. The position of the These dem<strong>and</strong>ing drilling projects to ob- mining vessel is then tain excellent raw materials are an impor- W@FWffiWffi wffi 6&b #& ffiffi WffiffiWHS changed by a certain amount, using the tant part of the Wirth Croup activities. The company is also actively involved in new anchor winches, the markets <strong>and</strong> technologies for obtaining drill bit is again lo- energy supplies in the future. One such exwered to the seabed, ample is the development of a facility for The large-diameter rock bit of approximately 7 m drilling diameter <strong>and</strong> the next borehole is drilled as descri- the foundation of an offshore wind park off the coast of the UK. X, 80 Schiff & Hafen 6/2006
Subsea Bornemann multi phase boosti ng systems Cero von der Wense, Axel Jäschke r <strong>Offshore</strong> reserves - especially those discovered in deep water - will be important in meeting future global oil dem<strong>and</strong>. Advanced technology <strong>and</strong> equipment that increase flow rates <strong>and</strong> permit longer subsea tiebacks will be needed to optimize production, recovery <strong>and</strong> financial performance. The subsea multiphase boosting systems of Joh. Heinr. Bornemann CmbH in Obernkirchen, the more than 150 years old Cerman manufacturer of twin screw <strong>and</strong> multiphase pumps & systems serving the oil <strong>and</strong> gas industry, are designed for the special rigors of deepwater development. Like pumps in all other applications, subsea multiphase boosting increase flow capacity by overcoming back pressure <strong>and</strong> friction. <strong>Offshore</strong>, the special challenge is to optimize flow rates in pipelines <strong>and</strong> production risers as water depths <strong>and</strong> tieback distances grow ever greater. Subsea wellheads connected to gathering stations that are then tied back to a surface platform can be an economical field development option. But as water depths increase, the energy needed to lift the well stream from the ocean floor to the surface platform also increases. Minimizing the number of gathering stations lowers development cost, but it also increases the length of flow lines. And a longer tieback to the surface platform is often the only way to make smaller discoveries viable. Subsea multiphase boosting can be an economical solution to the severe economic <strong>and</strong> environmental challenges of deep water. In these applications, pressures can reach 300 bar <strong>and</strong> temperatures may be as low as 4 'C. weather <strong>and</strong> sea conditions are too severe for an offshore platform. For smaller or economically marginal fields, subsea multiphase boosting can minimize offshore facilities, reducing capital <strong>and</strong> operating expense. Bornemann subsea multiphase boosting is suitable for: - Water depths from 20 to 3,000 m; - High internal <strong>and</strong> external pressures; - High flow rates <strong>and</strong> differential pressures. The solution The Bornemann pressure-compensated cartridge design is rated for high pressure. Only the inner pump insert is subjected to a high differential pressure. A common oil system lubricates <strong>and</strong> cools the motor as Subsea multiphase boosting well as the bearings <strong>and</strong> mechanical seals. Lubricating oil system pressure is kept above operating pressure to allow for a long References seal life. Field experience includes, implemented in Design advantages - A single unit can boost liquid <strong>and</strong> gas; - Parallel pumps can be easily installed; - lt is well suited for installation of redun- co-operation with Aker Kvaerner Subsea, Norway, the following applications: Canadian Natural Resources International Lyell field - North Sea (1 x SMPC 335) Performance data dant boosting systems; Capacity: 200 to 1,300 m3/hr - Robust construction is fit for the severe Differential pressure: 0 to 20 bar subsea environment; Discharge pressure: To 25O bar - One pump module weighs less than 50 t. Cas fraction (continuous): O Io 97% Design features - Cartridge design for pump <strong>and</strong> motor; Power consumption: 100 to 1 ,000 kW British Petroleum King field - Gulf of Mexico (2 x SMPC 335C) - Pressure-compensated lubricating oil Performance data system for motor, bearings <strong>and</strong> seals; - Pressure ratings to 500 bar; - Design lifetime of five years for all com- Capacity: 100 to 550 m3/hr Differential pressure: 0 to 50 bar Discharge pressure: To 350 bar Also, chemicals, as well as hyponents; - A pump module that is retrievable. Cas fraction (continuous): O to 95% Power consumption: 100 to 1,000 kW draulic <strong>and</strong> electrical control signals, must be delivered over long distances. For equipment installed in water deeper than 1,000 m, where intervention is difficult <strong>and</strong> costly, the top priority is reliability. Subsea equipment should operate for at least five years without failure, a goal that requires redundancy <strong>and</strong> a design that minimizes the number of components. & Application challenges Subsea multiphase boosting can provide access to remote offshore fields where The authors: Cero von der Wense, Vice President, Axel Jäschke, Product Manager, Joh. Heinr. Bornemann CmbH, Obernkirchen A broad range of existing subsea equipment is available for deepwater development "*ffi Schiff & Hafen 6/2006 81
Page 1 and 2: OMAE 2006 1r, ffi GOMAE.l;:; The 25
Page 3 and 4: c 150 € -o e 100 tr Asia -Pacific
Page 5: Conclusion and per

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