Gas Fields of the Cleveland Basin

Author: Paul Wood.

4 April Edwin 2013 - Edwin Bowles and John Dewar - Third Energy

At the meeting on the 4th April, programme secretary Steve Livera introduced John Dewar and Edwin Bowles of Third Energy, the holding company for Viking UK Gas Limited (VUKG).

John Dewar, a co-founder of Third Energy and previously a senior member of Shell's technology commercialisation team, gave an overview of VUKG. It is an integrated company developing local gas resources, mainly in the Vale of Pickering. Activities range from exploration, through appraisal and development of gas assets with the associated facilities. The company has four produced or producing gas fields in 407 sq. km acreage, pipelines and the Knapton power generation station.

Edwin Bowles then continued with a geological description, showing the overall stratigraphy of the Southern North Sea (SNS) basin. Although most SNS gas development has been offshore, one of the first wells was onshore, at Eskdale, drilled in 1937 by a predecessor of BP.

The Lockton (now Ebberston Moor) and Wyekham gas fields are part of the SNS petroleum system, with Carboniferous source rocks and reservoirs in the Carboniferous, Zechstein and Triassic Sherwood sandstone (Bunter). The seals are shales or halite.

The main Zechstein reservoir is the Kirkham Abbey Formation (KAF - Magnesian Limestone), usually With poor primary porosity from 4-8% but enhanced by fracturing. Only one of the four units within the KAF is a fair reservoir. The younger Brotherton carbonate is usually not a producing reservoir.

The best potential reservoir in the system is the Triassic Sherwood Sandstone (Bunter) but it requires a good migration path for gas through the Zechstein which is usually absent. In the Carboniferous, Westphalian reservoirs are absent locally, the main possibility being Namurian. These have been found but have low porosity and permeability. They could possibly be exploited using tight gas technologies such as 'fracking'.

Gas generation from the Carboniferous was widespread in the area until the Jurassic - there is also the possibility of oil in the Sherwood Sandstone.

Originally, gas exploration in the area was by British Gas and BP: Home Oil took a share in the 1960s. They discovered the Lockton gas field but it was abandoned after three years as most production came from fractures and was not sustainable. In 1980, Taylor Woodrow made the Kirby Misperton and Malton discoveries. In the 1990s, Kelt discovered Marishes and developed the Vale of Pickering fields. Tullow developed the Pickering Field in the 2000s.

Third Energy now hopes to reopen Lockton as well as improve production in some of the ageing fields using new technologies. They have recorded 3D seismic in several areas and acquired a gravity gradiometry survey to define Carboniferous and basement structures outside areas of seismic coverage.

They plan to develop Ebberston Moor, the undeveloped part of Lockton, using long offset horizontal wells.

John Dewar then concluded by giving an overview of the infrastructure, well sites, pipelines and the generating station (42MW) that produces sufficient electricity to power 40,000 homes.