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Offshore Oil & Ocean Engineering


July 2011 Issue

Floating Natural Gas Facility to Be Built Offshore Australia
Royal Dutch Shell plc (The Hague, Netherlands) approved the final investment decision for its Prelude floating liquefied natural gas (FLNG) project in Australia, the company said in June. Design and construction is set to begin on what will be the world's first FLNG facility at Samsung Heavy Industries Co. Ltd.'s (Seoul, South Korea) Geoje Island shipyards in South Korea.

Shell said it expects first production of LNG from its Prelude project 10 years from the field's initial discovery in 2007. The facility will stay permanently moored at the Prelude gas field for 25 years and should later produce from other nearby Shell fields. The facility will tap into around 3 trillion cubic feet equivalent of resources in the Prelude field, Shell said, with an expected production of about 110,000 barrels of oil equivalent per day.

Moored some 200 kilometers offshore Australia, the FLNG facility will produce gas from offshore fields and liquefy it onboard by cooling the gas, allowing Shell to access areas that would otherwise be too far away or costly to develop. Ocean-going LNG carriers will offload the liquefied gas, chilled to -162° C and shrunk in volume by 600 times, directly from the facility for delivery to markets worldwide. Until now, the liquefaction of offshore gas always involved piping natural gas to a land-based plant.

From bow to stern, the facility, designed to withstand Category 5 cyclones, will be 488 meters long. When fully equipped and with full storage tanks, it will weigh around 600,000 tonnes, which consists of about 260,000 tonnes of steel.

"FLNG technology is an exciting innovation, complementary to onshore LNG, which can help accelerate the development of gas resources," said Malcolm Brinded, Shell's upstream international executive director.

For more information, visit www.shell.com.

Exxon Mobil Makes Discovery in Deepwater Gulf of Mexico
After drilling its first exploration well since the deepwater-drilling moratorium was lifted, Exxon Mobil Corp. (Irving, Texas) announced in June a Gulf of Mexico oil discovery that could be the region's largest in the past decade. Combined with an oil and natural gas reservoir discovered in early 2010 and a natural gas resource encountered in 2009, these discoveries could yield up to 700 million barrels, Exxon said.

Exxon's most recent discovery, the Keathley Canyon (KC) 919-3 wildcat well, confirmed a second oil accumulation in KC block 919. Located 250 miles southwest of New Orleans in approximately 7,000 feet of water, the well, which workers continued to drill deeper after hitting oil, encountered more than 475 feet of net oil pay and a minor amount of gas in mostly Pliocene high-quality sandstone reservoirs.

Exxon encountered oil and natural gas at Hadrian North in KC919 and extending into KC918 while drilling in early 2010, with more than 550 feet of net oil pay and a minor amount of gas in high-quality Pliocene and Upper Miocene sandstone reservoirs. While drilling in 2009, the company encountered 200 feet of natural gas in Pliocene sandstone reservoirs at its Hadrian South prospect in KC964. For more information, visit www.exxonmobil.com.

Shell Launches Development of GOM Discovery
Royal Dutch Shell plc (The Hague, Netherlands) will make a multibillion dollar investment to develop its deepwater Cardamom oil and gas field in the Gulf of Mexico, the company said in June. The exploration plan was the first to be approved since the lifting of the U.S. government moratorium on drilling in the gulf.

The Cardamom project is expected to produce 50,000 barrels of oil equivalent (BOE) a day at its peak and more than 140 million BOE throughout its lifetime, Shell said. Cardamom is located roughly 362 kilometers southwest of New Orleans, Louisiana, in more than 800 meters of water.

The company will now move ahead with further development drilling and the installation of undersea equipment. The completed subsea system will include five well expandable manifolds, a dual 20-centimeter flowline and eight well umbilicals. Modifications to Shell's Auger platform will include additional subsea receiving equipment, a new production train and a weight mitigation system, which are expected to greatly increase the Cardamom liquid handling, cooling and production capacities, Shell said.

The potential of Cardamom was first recognized in the early development stages of the Auger platform but could not be fully assessed due to a layer of salt nearby, which affected the quality of traditional seismic images. Advances in seismic imaging and extended reach drilling overcame this issue, Shell said, and the discovery was confirmed by drilling a well from the Auger platform. The Cardamom discovery well has a measured depth of 9,642 meters, a reach of more than 4,570 meters and a vertical depth greater than 7,620 meters. Exploration wells were drilled more than 6.4 kilometers below the seabed. For more information, visit www.shell.com.

TCO's TDP-2 Plug Successfully Used as Pressure Vessel in UK
TCO In-Well Technologies UK Ltd. (Aberdeen, Scotland) announced in June the successful completion of the first remote opening of its Tubing Disappearing Plug 2 (TDP-2), a full-bore glass barrier system, on a subsea well on the U.K. Continental Shelf.

The operation, carried out for an oil major, was successfully completed with the TDP-2 glass plug being used as a secure ISO 14310 V0-certified barrier. The client planned for the TDP-2 to be used as a pressure vessel to set the production packer at 4,500 pounds per square inch. Once the packer was set, the completion string was then pressure tested for integrity.

Upon completion of the operation, and with the Xtree landed, the TDP-2 was then remotely pressure cycled to open without needing intervention.

"TCO UK has had a very successful start since the company was founded in late 2009 and was initially involved in a number of similar operations based on platforms in the U.K. Continental Shelf," said Rob Grassick, TCO UK's sales and marketing manager.

For more information, visit www.tco.no.


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