# Kotter and Logger oil and gas fields

The Kotter and Logger oil and gas fields are mid-size fields located in the Netherlands sector of the North Sea, about 40 km west of Den Helder and 107 km north west of Amsterdam. The Kotter and Logger oil fields produced oil from 1984/5 to 2015.

## The fields

The Kotter oil and gas fields are located in Block K18 of the Netherlands sector of the southern North Sea. The oil reservoir is a Cretaceous/Jurassic sandstone at a depth of 7,500 feet (2,300 metres) and comprises two accumulations in Vieland and Delfland sands. The gas reservoir is an Upper Rotliegendes sandstone at a depth of 4,217 to 4,337 metres, below Zechstein salt.
The Logger oil field is in the adjacent Block L16 and is also a Cretaceous/Jurassic sandstone lying at a depth of 7,215 feet (2,199 metres), it has a thickness of 10 to 30 metres.
The Kotter oil field was discovered by Conoco in August 1980, the Logger oil field in March 1982, and the Kotter gas field in 1992, both also discovered by Conoco.
The properties of the reservoir/ wellhead fluids are:
Wellhead fluid properties :
| Oil fields | Oil fields | Oil fields | Kotter Gas field | Kotter Gas field |
| Oil property | Kotter | Logger | Gas composition and property | Value |
| API gravity | 32° | 34° | Methane | 86.62% |
| Gas Oil Ratio | 45 scf/bbl | 48 scf/bbl | Carbon dioxide | 10.79% |
| Viscosity | 4.93 cP | | Nitrogen | 1.02% |
| Sulfur | Low | Low | Hydrogen sulfide | Nil |
| Oil in place | | 29 million barrels | Gross calorific value | 35.8 MJ/m$^3$ |

## Development

The Kotter and Logger oil fields were developed though a number of platform installations.
Offshore installations :
| Installation | Block | Configuration | Water depth | Function | Type | Legs | Well slots | Installed | Production start | Production to |
| Kotter Production Platform | K18 | Bridge linked | 27 m | Processing, accommodation (50 crew) | Steel jacket | 8 | – | May and July 1984 | September 1984 | Helder A by 27.4 km 12-inch diameter pipeline |
| Kotter Drilling Platform | K18 | Bridge linked | 27 m | Drilling and wellheads | Steel jacket | 6 | 24 | April and June 1984 | September 1984 | Kotter Production |
| Logger Drilling Production Platform | L16 | Bridge linked | 33 m | Drilling, wellheads and production | Steel jacket | 4 | ? | July and August 1985 | September 1985 | Kotter Production by a 19 km 8-inch diameter pipeline |
| Logger Utilities Platform | L16 | Bridge linked | 33 m | Utilities and accommodation (28 crew) | Steel jacket | 4 | | July and August 1985 | September 1985 | |
Oil from Logger was exported to Kotter. Oil from Kotter was exported to the Helder A platform and the combined flow sent to Amsterdam. Produced gas from both oil fields was flared. The K18-FB gas field adjacent to Kotter is a stranded asset with no gas transportation infrastructure and remains undeveloped. The Logger installation had a water injection capability of up to 4 injection wells. Injection water was transferred from Kotter to Logger through a 19 km 6-inch pipeline.
The Kotter production facility was originally designed for these throughputs.
| Oil production | 25,000 bopd |
| Water production | 49,000 bbl/d |
| Liquids production | 54,000 bbl/d |
| Produced water | 50,000 bbl/d |
| Water injection | 60,000 bbl/d at 180 bar |
The Logger installation had a production capacity of 10,000 bbl/d of oil.
The K18 Golf facility aimed to produce 1.0 to 1.4 million cubic metres of gas per day.
The Kotter and Logger fields were originally owned and operated by Conoco until they were taken over by Wintershall. Production ceased in 2015 and the wells and installations were decommissioned and decontaminated. The platforms and jackets were removed from the field in 2019.