Halten Terrace, 200km off the coast of Norway
Songa Delta semi-submersible rig
75-155mmboe of oil and associated gas
The Maria prospect is located in the Norwegian Sea about 200km off the coast of Norway. The field is operated by Wintershall Norge (25%). Other equity holders are Concedo (10%), Spring Energy Norway (15%), Centrica Resources (20%) and Faroe Petroleum Norge (30%).
The Maria prospect is located on the centre of Halten Terrace, 3km to the north-west of Smorbukk Sor and 5km south to the Trestakk oil discovery. The Maria is divided into two segments – the Maria South and the Maria North. Both segments are located up the slope of a surface on the south-west and north-east of the 6406/3-5 well.
The Maria prospect includes Blocks 6407/1 and 6406/3, which lie in a water depth of 243m. These blocks occupy an area of 496km².
Drilling operations on Maria prospect are being carried out under exploration licence PL 475 / 475 BS. The first well was drilled in 1988. The 6406/3-5 well, located down dip of the Maria prospect, encountered oil shows.
In May 2010, the 6406/3-8 T2 well was drilled in the Maria South segment. This was the first exploration well drilled on licence 475BS. The well was drilled to a vertical depth of 4,216m in the lower Jurassic Tilje formation. The Songa Delta drilling rig was used in the operations.
The aim of the drilling was to prove hydrocarbons in the early to middle Jurassic formations. The oil reserves were discovered in the main target Garn formation in Jurassic sandstones. A preliminary log analysis of the discovery indicated that the reservoir is denser than the anticipated gross oil column of 64m. It has a high net-to-gross ratio and holds huge volumes.
Initial analysis suggested that the oil has properties similar to that discovered in the nearby Trestakk field.
Wintershall acquired extensive data to assess the productivity of the reservoir and substantiate the discovery. The programme included coring, wireline logging, fluid sampling and mini drill stem tests.
The preliminary analysis indicates a level of stock tank oil initially in place (STOIIP) of between 250m and 520m barrels of oil equivalent (mmboe). Around 75 to 155mmboe of recoverable volumes of oil and associated gas are estimated to be in the field.
Det Norske and Wintershall Norway signed a contract in March 2009 to utilise Songa Delta for a period of three years. The unit will drill around 20 wells during a three year contract.
The column-stabilised drilling unit can be operated in water depths up to 700m. The rig has a length of 122m, width of 80m and a height of 41m. It features 1,020m² of pipe decks and 200m² of additional lay down area.
Drilling equipment includes Continental Emsco derrick, Oilwell E-3000 draw works and Emsco T-4950 rotary.
A Maritime Hydraulic 3-arm fully mechanised system, a Maritime Hydraulic 1898 Iron Roughneck and MH- Pipe rack crane, feeding table and drill-floor mounted manipulator arm are available for pipe handling. Other systems include a cementing unit, three mud pumps, a degasser and a centrifuge.
Twelve Pusnes type CWMS mooring winches, and Stevpris Mk5 anchors and Simrad HPR 410 positioning system are installed on the platform. Subsea systems include a BOP (blow out preventer), a Hughes diverter system, a Cameron hydraulic subsea BOP system, a choke manifold, an x-mas tree skidding system, tensioners and an underwater TV system.
Odfjell Well Management provides well management services. Baker Hughes is responsible for all well services including directional drilling, logging, processing of drilling fluids and cuttings.