Steve Furnival from National Grid Carbon reported on a major new CO2 storage assessment which forms part of the proposed White Rose CCS project. The scheme could eventually link several large CO2 sources in the Yorkshire and Humberside region with a large saline aquifer under the North Sea. Steve outlined the news at GHGT-12, in Austin Texas. He explained that there has been an active search for a suitable large saline aquifer or depleted gas field to store the gas from the adjacent onshore area. There are two candidate formations with suitable reservoir properties, the Rotiegend formation, which has a number of depleted gas fields, and the younger Triassic Bunter Sandstone. A review of the depleted gas fields revealed that they have insufficient capacity for the quantity of onshore CO2. Attention has subsequently focussed on the Bunter Sandstone which is a saline aquifer more than 1,000 m below the surface. The formation extends over a structure known as 5/42 approximately 65 km off the Humber coast. Two previous wells have provided some useful information, but more detail was necessary to verify the reservoir characteristics. In 2013 a new well was drilled to provide more detailed technical data. 180m of new core, sonic and density logs and petrophysical analysis have revealed a 200m thick section with good porosities ranging from 15% to 30% and permeabilities from 10 to 1,000 mD. A suite of tests were used to determine the pressure threshold of the caprock and the properties of the reservoir. Fluid samples from the aquifer were sampled and analysed to determine the salinity which influences the solubility of CO2. Other favourable characteristics including the wide extent (200 km2) of the formation and the lack of faults which make this saline aquifer a promising candidate for CO2 storage. The new data acquired from this recent wellbore continues to be analysed. It will be used to build a revised geological model of the prospective reservoir.

The proposed White Rose project will initially take CO2 from a 450 MWe demonstration oxyfuel capture plant installed at the Drax coal-fired power station. It could, in the future, include other emitters in the region. The proposed pipeline connecting Drax to the offshore storage site will initially carry 2.65 M tonnes of CO2 per year, but it has been designed to have an annual capacity of up to 17 M tonnes.

The work done on appraisal drilling and subsurface characterisation and development of the storage site designated as 5/42 has been funded by the EU’s European Energy Programme for Recovery (as part of the, Don Valley Power Project),  the UK’s Energy Technology Institute and National Grid Carbon.