The Horne field, discovered in 1992 by Hamilton Oil Company, straddles the boundary between Blocks 53/3c and 53/4b-F1. The 53/3c-3 discovery well was drilled vertically on the structure. It encountered Rotliegendes reservoir at 6,320 ft. TVDSS and reached a total depth of 8,994 ft. TVDSS in the Carboniferous. The well was successfully tested at a rate of 55 mmscfd. The gas contained 6.5% N2 and was very dry. The well was suspended as a gas discovery. The Wren field lies in Block 53/4b, and was discovered in 1997 by ARCO British Ltd. Well 53/3c-6 was drilled directionally from 53/3c due to proximity to the shipping lane.
The reservoir was encountered at 6,430 ft. TVDSS in the Rotliegendes Leman Sandstone interval, and reached a total depth of 7,394 ft. TVDSS in the Carboniferous. The well was not tested, due to mechanical reasons, but suspended as a gas discovery. H & W were developed together and both wells started producing in June 2005. The H&W minimum facility is a 2 well gas production platform located in Block 53/3c of the Southern North Sea, 65 kilometres East of the Bacton Terminal off the coast of Norfolk, in 40.6m water depth. The co-ordinates of the H&W Platform are WGS84 – 52° (54’ 11.85) North, 2° (35’ 54.91) East. UTM co-ordinates Zone 31U Eastings: 473092.023 Northings: 5861799.431. The platform is aligned over two preinstalled conductors with the wellhead and processing facilities tied back to the SNS Thames complex.
The jacket consists of a 3-leg tripod skirt pile frame with a bottle-elevation profile. The jacket is 61m in length from the seabed to the head of the topsides support transition frame. The upper jacket section triangular profile measures 4m along each face tapering to 23m at the jacket base. The 3 No. 48” diameter piles 68m long with a penetration of 42m are driven through the 20m long sleeved lower jacket legs. The pile to jacket connection is formed via grouted connections. The topsides structure consists of a cellar and weather deck, with framing dimensions of 8m x 7m x 6.1m high. The topsides are supported off the jacket transition at elevation LAT +20.0m. The topsides framing consists of a 4 deck leg portal type structure with horizontal diaphragms incorporated in each deck. There are no processing facilities on the platform, it is essentially a wellhead platform only. There is no accommodation and the facility is normally unmanned. There is no helideck and access to the platform is via boat only. Control of the platform from Thames is via line of sight microwave, there is no umbilical between the two facilities. Production is routed to the Thames complex, after separation and metering, gas is exported through a 24″ pipeline to the Bacton Gas Terminal, Norfolk.
The platform seabed tie in line inventory is as follows: • 10” Gas Export Pipeline to Thames 49/28A facility • 21/2” MEG/ Inhibitor line piggy backed to 10” Gas Export Line • 8” Gas Flow line from the Wissey Facility. • Control Umbilical to Wissey • The H&W platform appurtenances consist of the following: • 2 No. 30” Conductors • 10” Export Riser. • 3” MEG/ Inhibitor Riser • 8” Import Riser. • 2 No. 8” Future Risers • 10” J-Tube