The Tor oil field is a crude oil and associated gas producing field in the Norwegian sector of the central North Sea. Production of oil and gas started in 1978 and peak oil and gas was achieved in 1979. The field was shut down in 2015 and, following the completion of new wells, started up again in 2020.
The characteristics of the Tor field reservoir are as follows.[1] [2] [3]
| Tor | ||
| Reservoir | Late Cretaceous and early Paleocene | |
| Block | 2/4 and 2/5 | |
| Reservoir depth, metres | 3,200 | |
| Gas Oil Ratio, scf/bbl | 1,500 | |
| API gravity | 43° | |
| Sulfur | 0.1% | |
| Pressure, psia | 7,135 | |
| Discovered | November 1970 | |
| Original recoverable reserves | 150-260 MMbbls oil, 560-900 bcf gas | |
| Now in reserve (2023) | 4.3 MMSm3 oe oil, 0.4 MMSm3 oe Gas, 0.3 MMSm3 oe NGL |
The current (2024) owners of the Tor field are:
| TotalEnergies EP Norge AS | 48.19879 | |
| ConocoPhillips Skandinavia AS | 30.65799 | |
| Vår Energi ASA | 10.81656 | |
| Sval Energi AS | 6.63922 | |
| Petoro AS | 3.68744 |
The field has been developed with an offshore platform facility, designated Tor E. [4]
| Block | 2/4 | |
| Latitude | 56.642072°N | |
| Longitude | 3.326958°E | |
| Water depth, metres | 70 | |
| Type | Fixed steel | |
| Platform design | Kvaerner Engineering | |
| Topsides design | Worley Engineering | |
| Function | Drilling, production, accommodation | |
| Bridge | To flare tower | |
| Substructure, tonnes | 5,275 | |
| Topsides, tonnes | 6,448 | |
| Legs | 8 | |
| Piles | 8 | |
| Well slots | 18 | |
| Accommodation | 58, in 1982 this was replaced by 96 berth accommodation | |
| Installed in field | June 1975 | |
| Design throughput | 101,600 bopd, 89 MMscfd gas | |
| Processing | 3-phase (oil/gas/water) separator operating at 500 psig, gas dehydration by glycol | |
| Export | 7.5 mile, 14-inch gas pipeline and 12-inch oil pipeline to the Ekofisk R |
Production started in July 1978. The production profile was as follows. Units are million Standard cubic metres oil equivalent.
| 1978 | 1.207351 | 0 | 0.340779 | |
| 1979 | 4.526296 | 0.139954 | 1.156825 | |
| 1980 | 3.589572 | 0.277508 | 1.287604 | |
| 1981 | 1.883789 | 0.229188 | 1.177126 | |
| 1982 | 1.53073 | 0.272185 | 1.341813 | |
| 1983 | 0.967933 | 0.254676 | 1.08709 | |
| 1984 | 0.86721 | 0.217469 | 0.935608 | |
| 1985 | 0.824205 | 0.201494 | 0.779392 | |
| 1986 | 0.624547 | 0.116754 | 0.463587 | |
| 1987 | 0.477363 | 0.088523 | 0.343058 | |
| 1988 | 0.482864 | 0.095564 | 0.31813 | |
| 1989 | 0.510003 | 0.08923 | 0.312373 | |
| 1990 | 0.472642 | 0.068414 | 0.241651 | |
| 1991 | 0.346273 | 0.037771 | 0.161191 | |
| 1992 | 0.362346 | 0.031401 | 0.144108 | |
| 1993 | 0.345858 | 0.022479 | 0.094797 | |
| 1994 | 0.338599 | 0.019134 | 0.074034 | |
| 1995 | 0.338633 | 0.017823 | 0.067366 | |
| 1996 | 0.359242 | 0.01719 | 0.062885 | |
| 1997 | 0.34683 | 0.017306 | 0.057085 | |
| 1998 | 0.230711 | 0.010977 | 0.036404 | |
| 1999 | 0.221491 | 0.010784 | 0.037131 | |
| 2000 | 0.255572 | 0.010677 | 0.040556 | |
| 2001 | 0.256831 | 0.00988 | 0.034708 | |
| 2002 | 0.213535 | 0.00818 | 0.024964 | |
| 2003 | 0.162892 | 0.00666 | 0.017144 | |
| 2004 | 0.197161 | 0.008346 | 0.021414 | |
| 2005 | 0.180349 | 0.007957 | 0.019744 | |
| 2006 | 0.164293 | 0.008513 | 0.023813 | |
| 2007 | 0.314827 | 0.015891 | 0.053809 | |
| 2008 | 0.307169 | 0.012521 | 0.032965 | |
| 2009 | 0.291949 | 0.010127 | 0.024138 | |
| 2010 | 0.237053 | 0.007082 | 0.013999 | |
| 2011 | 0.219272 | 0.004878 | 0.008242 | |
| 2012 | 0.22339 | 0.005151 | 0.007459 | |
| 2013 | 0.198807 | 0.004522 | 0.008314 | |
| 2014 | 0.196979 | 0.004482 | 0.008718 | |
| 2015 | 0.180988 | 0.003551 | 0.006555 | |
| 2016 | 0 | 0 | 0 | |
| 2017 | 0 | 0 | 0 | |
| 2018 | 0 | 0 | 0 | |
| 2019 | 0 | 0 | 0 | |
| 2020 | 0.017476 | 0.000875 | 0.001435 | |
| 2021 | 0.804716 | 0.036559 | 0.073409 | |
| 2022 | 0.719511 | 0.035468 | 0.088719 | |
| 2023 | 0.583491 | 0.035511 | 0.117698 |
Oil was initially produced by pressure reduction, from 1992 water flood was introduced.
Export from Tor was initially routed by two pipelines to Ekofisk R. Subsequently, in 1998, fluids were routed to Ekofisk 2/4 J.
In 1989 a gas lift module was added, this allowed eight wells to use gas lift, formerly only three wells.
In 2019 two subsea templates with eight horizontal production wells were tied back to Ekofisk centre.
The remaining recoverable reserves in 2023 were 4.3 MMSm3 oe oil, 0.4 MMSm3 oe Gas, 0.3 MMSm3 oe NGL.