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Brown & Root Energy Services Installs The Malampaya Platform Concrete Gravity Sub-Structure Ahead Of Schedule
First CGS installed in South China Sea
HOUSTON, TX -Brown & Root Energy Services (BRES), a business unit of Halliburton Company (NYSE:HAL), announced today that it has installed the 91,000 tonne Malampaya Concrete Gravity Sub-structure (CGS) offshore Palawan Island in the Philippines. The CGS installation was achieved three months ahead of schedule and marks the first such installation in the South China Sea.
The CGS construction and installation was carried out safely and in compliance with the Philippines' environmental standards. Conformance with two Environmental Compliance Certificates has been monitored by the Philippines Department of Environment and Natural Resources and the Subic Bay Metropolitan Authority. BRES wishes to acknowledge the skills and hard work of its Filipino workforce, who were key to the safe and timely delivery of the CGS. For example, there have been no Lost Time Incidents since first concrete was poured to installation of the CGS offshore Palawan.
Shell Philippines Exploration B.V. (SPEX) is the contractor to the Philippines government to develop the licence area defined by Service Contract 38 and in 1998 SPEX awarded contracts to BRES to design, procure, install and commission the Malampaya Platform. BRES subcontracted the design, construction, installation and commissioning of the base of the platform, called the Concrete Gravity Sub-structure (CGS) to the Malampaya CGS Alliance comprising John Holland, Ove Arup and Van Oord.
Some details of each phase of the construction, preparation, float out, tow and installation of the CGS are set out below.
Construction - The First CGS to be Constructed in Asia
The CGS was constructed at Green Beach, Subic Bay, in the Philippines. Green Beach provided a flat area, large enough to cater for fabrication, construction and residential areas. Access to the site was by boat with all materials and personnel being transshipped across Subic Bay. The site was formerly used by the US Navy as a target range, consequently extensive explosive ordinance surveys and disposal activities were required prior to mobilizing personnel and construction equipment. The self-contained residential area provided accommodation for some 1,500 Filipinos and a small expatriate contingent.
The CGS was constructed in a specially built graving dock that involved the excavation of 320,000 cubic meters of earth to create a dock with a floor 12 meters below sea level. This excavation started in December 1998 and construction of the CGS commenced in May 1999.
Seabed Preparation
To provide a level and even seabed for the CGS at the intended installation site a series of 361 mounds of crushed rock with an average height of 1.4 meters were placed on the seabed. These mounds were designed to flatten out during the installation of the CGS to form an even layer of rock with a minimum thickness of 500 millimeters thereby smoothing the contours of the seabed. The mounds were completed on 16 May 2000 and involved the placement of 17,000 tonnes of rock. This operation marked the first time that a seabed had been specially prepared to accept a CGS.
Dredging
To allow the CGS access to the open seas, a channel measuring 150 meters wide and 12 meters deep was dredged from Green Beach to the deep waters of Subic Bay. This activity was completed in the thirteen days to 28 May 2000 and relocated a total of 250,000 cubic meters of soil through a 750 meter floating pipe to a designated disposal site within the bay.
On 16 May 2000 seawater was allowed to flow into the graving dock. The remaining earth between the CGS and Subic Bay, called a bund wall, was then dredged away.
Float Out & Tow
On 28 May 2000 the final ballast water in the CGS was pumped out and the empty and sealed CGS started to float in its dock. At 2:00pm local time later on the same day the CGS was maneuvered to sheltered waters within the Bay and three seagoing tugs, with a combined towing force of 30,000 brake horse power were connected to the towlines. The external open cells of the CGS were then re-flooded to provide greater stability for the sea tow. Four hours later these tugs, escorted by a command vessel and a reserve tug, commenced the 209 nautical mile tow of the CGS to offshore Palawan.
Four days after leaving Subic Bay the CGS arrived at the offshore installation site. At this point the fourth tug was connected to the CGS to assist in holding the CGS steady. Rigging on the CGS was then re-configured such that the tugs were spread in a star formation around the CGS, with one at each corner. To provide greater positional stability the tugs were connected to pre-laid seabed anchors.
Installation - The First CGS to be Installed in the South China Sea
On the afternoon of 1 June the internal compartments of the CGS were ballasted with sea water, allowing a controlled descend to the seabed. This ballasting operation was completed in 11 hours, with the CGS finally resting less than three meters from its target location, 43 meters below sea level, 50 kilometers from Palawan at 15 minutes past midnight on 2 June 2000.
The positional accuracy was achieved by using pre-installed seabed transponders to determine the exact position of the CGS as it moved through its controlled descent. Adjustments to the CGS's position were made through synchronized changes in pulling forces on each of the four tugs.
The operation to protect the CGS from being undermined by wave and tidal action has now commenced. This will involve placing 3,000 tonnes of rock around the four corners of the base of the CGS. When this scour protection is completed the CGS will be permanently ballasted down by placing 75,000 tonnes of iron ore in its open cells. This weight is designed to keep the CGS in its location even during a one in 10,000 year earthquake.
Brown & Root Energy Services supplies engineering, construction, operations and maintenance services to the upstream oil and gas industry worldwide. Its primary role is the engineering, project management, construction and operation of the facilities that are utilized for the production and transportation of oil and gas.
Founded in 1919, Halliburton Company is the world's leading diversified energy services, engineering, energy equipment, construction and maintenance company. In 1999, Halliburton's consolidated revenues were $14.9 billion and it conducted business with a workforce of approximately 100,000 in more than 120 countries.
Brown & Root ENERGY SERVICES INSTALLATION OF CONCRETE GRAVITY SUB-STRUCTURE
Facts & Figures
The CGS is 112 meters long, 83 meters broad and has a caisson height of 16 meters. The four 11 meter diameter shafts extend 40 meters from the top of the caisson roof. Some 32,000 cubic meters of concrete, 12,000 tonnes of reinforcing steel and 750 tonnes of pre stressing steel strands were used in its construction.
Operation
The CGS will be able to store up to 385,000 barrels of condensate that will continuously flow from the topsides during gas production. The CGS has been designed to store the condensate "dry". As such the CGS will, when in operation, initially be filled with an inert gas. As condensate is produced the gas will be gradually displaced. Periodically, a shuttle tanker will connect to a loading buoy located three kilometers from the CGS and the stored condensate will be pumped to the tanker while further inert gas is added to the CGS.
In March 2001 the 10,500 tonne Malampaya topsides will be installed over this CGS and following offshore commissioning, the Malampaya platform will be ready to supply gas to power plants by 1 October 2001. The Malampaya development will provide the Philippines with a major source of indigenous, clean and dependable power.
Contact
Taryn Rock
taryn.rock@halliburton.com
Halliburton Company
Public Relations
Europe/Africa Region
(p) 44.1372.86.6693
Wendy Hall-Nantz
wendy.hall@halliburton.com
Halliburton Company
Public Relations
Americas
(p) 713.676.5227
Monique Mathieu
monique.mathieu@halliburton.com
Halliburton Company
Public Relations
(p) 65.422.2359
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