Cod oil gas and condensate field
The Cod oil gas and condensate field is a gas and associated natural gas liquids (NGL) production field in the Norwegian sector of the central North Sea. Production of oil and gas started in 1977, peak gas and NGL was achieved in 1980. Production ceased in 1998 and the field installation was dismantled in 2013.
The field
The characteristics of the Cod field reservoir were as follows.[1] [2] [3]
| Field | Cod |
| Block | 7/11a |
| Reservoir | Paleocene sand |
| Reservoir depth | 9,700 feet |
| API gravity | 49° |
| Oil Gas ratio (OGR) | 70 bbl/mmscf at 210 °F (barrels per million standard cubic feet) |
| Pressure | 5,565 psi |
| Discovery | June 1968 |
| Recoverable reserves | 20 MMbbls condensate (million barrels) oil; 250 bcf (billion cubic feet) gas |
Owner and operator
The field was owned and operated by ConocoPhillips Skandinavia AS.[2]
Infrastructure
The Cod field was developed through an offshore installation[1] [2]
| Name | Cod |
| Coordinates | 57.069553°N 2.434722°E |
| Block | 7/11 |
| Water depth, metres | 72.5 |
| Bridge | To flare tower |
| Installed | May 1975 |
| Function | Drilling, production, accommodation |
| Production start | December 1977 |
| Type | Fixed steel |
| Substructure weight, tonnes | 5,094 |
| Topsides weight, tonnes | 5,167 |
| Number of wells | 9 |
| Legs | 8 |
| Piles | 8 |
| Flare | Tripod tower bridge link |
| Status | Dismantled |
| Export, liquids and gas | 46.9 mile, 16-inch, 2-phase pipeline to Ekofisk |
| Design contractor | Kvaerner |
| Jacket fabrication | UIE St. Wandrille |
| Deck fabrication | UIE St. Wandrille |
| Accommodation | 52 |
Production
The design production capacity of Cod was 17,400 bopd (barrels of oil per day) and 117 mmscfd (million standard cubic feet per day) of gas.[3] Initial separation was at 500 psia (88.3 bar). There was a single 3-phase separator with provision for 350 bpd of produce water. The produced gas was dried in a glycol contactor. Condensate was dried in coalescing filters. Dehydrated oil and gas streams were combined and sent to Ekofisk in a single 2-phase pipeline. [1]
Cod also received gas from the Ulla field which passed directly to the export pipeline.[1]
Production from the Cod field was by natural depletion. The oil, natural gas liquids (NGL) and gas production profile of the Cod field is as shown.[3]
Cod production profile
| Year | Oil (million standard m3 oil equivalent | NGL (MSm3OE) | Gas (MSm3OE) |
|---|---|---|---|
| 1977 | 0.001563 | 0 | 0.004224 |
| 1978 | 0.067707 | 0 | 0.13767 |
| 1979 | 0.285336 | 0.034961 | 0.481982 |
| 1980 | 0.465008 | 0.106834 | 0.843338 |
| 1981 | 0.342374 | 0.088603 | 0.69129 |
| 1982 | 0.3224 | 0.104771 | 0.757831 |
| 1983 | 0.283257 | 0.125424 | 0.730345 |
| 1984 | 0.19131 | 0.086764 | 0.528718 |
| 1985 | 0.153451 | 0.083159 | 0.454683 |
| 1986 | 0.125805 | 0.068082 | 0.404842 |
| 1987 | 0.081413 | 0.048838 | 0.280762 |
| 1988 | 0.100118 | 0.067628 | 0.353651 |
| 1989 | 0.070958 | 0.046021 | 0.255183 |
| 1990 | 0.057171 | 0.034896 | 0.194441 |
| 1991 | 0.051321 | 0.025296 | 0.172983 |
| 1992 | 0.048911 | 0.022525 | 0.171408 |
| 1993 | 0.045536 | 0.021368 | 0.157185 |
| 1994 | 0.046297 | 0.021127 | 0.155257 |
| 1995 | 0.0469 | 0.022374 | 0.163722 |
| 1996 | 0.041718 | 0.019423 | 0.14773 |
| 1997 | 0.032772 | 0.016849 | 0.117144 |
| 1998 | 0.017806 | 0.011088 | 0.074871 |
Cod ceased in production in 1998 and the installation was removed from the field in 2013.###nor