"The installation of the trilateral well junctions at Troll in less than seven days was an important step in the development of this product. We are sure that these practices can be utilized in other fields on the Norwegian shelf and around the world," said Jorunn Saetre, country vice president for Norway, Halliburton Energy Services.
Norsk Hydro has chosen multilateral wells to reach the most inaccessible oil reservoirs at the Troll field, where the oil-bearing layers can be as thin as 10 meters. This requires the oil to be drained through long horizontal wells. By having several conduits reaching into the shallow reservoir, it is possible to produce more oil at a lower cost.
"The construction of a trilateral subsea well is a breakthrough in multilateral technology, confirming that even more branches can be joined together and provide a way to drain more oil from the Troll field and other complicated reservoirs in the Norwegian continental shelf," said Tor Madsen, section manager for petroleum technology - Troll Field, Norsk Hydro.
The first multilateral well installation from a floating rig was carried out at the Troll field in 1997 by Halliburton. An additional 16 multilateral wells have been installed in that field since that time, which has made it possible to increase production to rates once thought unachievable. The trilateral (three horizontal branches) well design is the most recent breakthrough. The third branch will make it possible to produce 1.5 million barrels of additional oil from the well, while keeping the well junction pressure tight and preventing sand from entering the well.
The multilateral project and the application of ITBS system technology in the Troll field have been nominated for the Offshore Northern Seas 2002 Innovation Award. The award will be presented by the Prime Minister of Norway during the ONS opening ceremony in Stavanger, Norway, on August 27, 2002.
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