Subsea/Surface Systems

Oceaneering recently completed a full turnkey installation for Mariner Energy on the Apia field.

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Deepest CT tieback performed on Apia

Oceaneering recently completed a full turnkey installation for Mariner Energy on the Apia field. The company took on the project management roll for this single well tieback. Norb Gorman, Manager of oilfield projects, said Oceaneering saw Apia as a chance to integrate a variety of products and services in a size and depth range it was comfortable working in. - Oceaneering multi-service vessel, Ocean Intervention, provided installation work on the recent Apia project for Mariner Energy.

Apia flowed first oil on April 29, beating the target date of May 1. The field consists of a single well located in Garden Banks Block 73 and tied back to the El Paso Energy Platform A in Garden Banks Block 72, 15,000 ft away.

Gorman said the firm turnkeyed everything but the drilling rig. The topsides facilities were contracted out to Lowe Engineering; the subsea tree was purchased from Cameron; the two 4.5-in. coiled tubing flowlines were manufactured by Precision Tubing. Other than these items, all manufacturing was done in-house, Gorman said. Work included the installation of the subsea christmas tree system, manufacture and installation of the well control skid, manufacture of the chemical injection unit, manufacture and installation of an electro-hydraulic control umbilical, design, fabrication and installation of a dual 10.75-in. J-Tube assembly on the host platform, purchase and installation of the flowlines, supplying the installation and workover controls, supply of and installation of the topsides from Lowe, project management and engineering services.

Apia was not the firm's first turnkey. Gorman said Oceaneering turnkeyed subsea tiebacks for Kerr-McGee at West Cameron 648, and ATP's shallow water project in High Island 827. While Apia is not near the record for reeled pipe installation, Gorman said technically it set a record for the installation of coiled tubing. At 740 ft water depth, it will be a record that is short lived. Mariner is already looking at installing coiled tubing flowlines on the Black Widow prospect in 1,840 ft water depth. Well testing recently was completed on the Ewing Bank Block 966 field, at a rate of 6,500 b/d and 6.3 MMcf/d. The plan is to tie this field back to British Borneo's Morpeth mini-TLP platform in Ewing Bank 921 later this year.

Oceaneering will not bid on the turnkey for the Black Widow, Gorman said. Mariner will oversee the project engineering on Black Widow, but Oceaneering will provide the controls system, umbilicals, and termination assemblies for Black Widow as well as installation.

Fuel cell AUV in water

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Hugin AUV vehicle prepares to dive during a routine survey for the Norwegian Underwater Intervention.
Click here to enlarge image

C & C Technologies and Kongsberg Simrad are developing an autonomous underwater vehicle (AUV) called the Hugin 3000. The goal of this AUV is to provide a cost-effective alternative to deep-towed technology. One of the big hurdles in developing a practical AUV is power. Batteries are not only heavy, but don't have much range. The unit is powered by a unique aluminum oxygen fuel cell developed in conjunction with the Norwegian Defense Establishment (FFI). According to C&C, the unit can operate without recharging for up to 40 hours, depending on payload, power load, and the vehicle's speed.

The new AUV and its launch-and-recovery system (LARS), will be maintained in one of three 20-foot cargo containers that can be airfreighted to a work site anywhere in the world. The AUV system will be integrated with an "acoustic tether" to monitor data acquisition and optimize system performance.

The Hugen has a depth rating of 3,000 meters and integrated survey sensors including Simrad EM2000 multibeam bathymetry and imagery system, Edgetech Chirp side scan sonar, Edgetech Chirp sub-bottom profiler, and an optional magnetometer.

Manufacturing of the new unit is underway and sea trials began in May 2000. Kongsberg Simrad is developing the vehicle and its control system. C&C is developing the payload system. C&C reports that one major oil and gas company has already committed for Hugin 3000 survey work.

Truss spar contract awarded to partners

Though Aker Maritime and J Ray McDermott have agreed to go their separate ways, their former joint venture, Spars International, still has the ability to attract new business. Kerr-McGee recently awarded Spars the contract to provide a truss spar for the development of the Nansen field in the Gulf of Mexico.

Nansen is located in East Breaks Blocks 601, 602, and 646, in 3,700-ft water depth. The development consists of eight wells connected to dry trees on the spar. While there currently are three spars in place in the Gulf of Mexico, these are all caisson spars. Nansen will be the first application of Spars International's truss design. While a caisson spar is basically a long steel tube, the truss spar differs in its lower section. Solid near the surface, the deeper portion of the truss spar is made of an open lattice of steel beams. The hull designed for Nansen will measure 543 ft in length, with a diameter of 90 ft, allowing for a displacement of 30,000 metric tons. Aker will provide engineering, procurement, fabrication and delivery of the hull and mooring system. J Ray McDermott will deliver the production risers. Delivery is scheduled for the fourth quarter of next year.

Dense sands require a bigger hammer

Horizon Offshore upgraded from the Delmag D100-13 diesel pile hammer to the new D200-42 for a development platform project off Ecuador. The D200-42 is claimed to be the world's largest operational diesel pile hammer. Horizon performed the installation using its derrick barge Pacific Horizon. The project required Horizon to install two 48-in. piles and two 60-in. piles, each 420-ft in length. The platform was placed in 132-ft water depth.

Installation of the piles began using the D100-32 hammer. The plan was to drive the first 360-ft of the piles with this smaller hammer and then switch over to the D200-42 for the final section. The plans changed when unexpectedly dense sands were encountered at 58 ft. BML. These sands created higher than expected resistance and the more powerful hammer was brought into service early. At 170 ft BML, the D200-42 was brought in.

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