These five storage development plans are standalone documents which contain details of the characterisation, modelling, schedule and budget associated with the development of each site to accept the material volumes of CO2 supply required by the ETI Balanced Scenarios work. The reports are also accompanied by downloadable digital models for the Eclipse reservoir simulator. These provide a platform for further work and analysis from other industrial and academic workers.
D10 – Bunter Closure 36 Storage Development Plan – 10113ETIS-Rep-13-03
The Bunter Closure 36 site is one of many dome shaped/ elongate anticline structural closures within the Triassic Bunter Sandstone of the Southern North Sea. It is approximately 150 Km off the Yorkshire coast and a smaller “brother” of the Endurance storage site studied as part of the UK CCS commercialisation programme. The structure is brine-filled however there are some gas fields in the Bunter Sandstone to the north. The proposed development comprises 5 wells from an unmanned platform with CO2 supplied by pipeline from the Yorkshire coast. The project plan accommodates 7MT/yr for 40 years through 4 active injectors. and the project will require one further appraisal well to address remaining uncertainties with reservoir quality distribution and also aquifer connectivity. Modelling suggests that ultimate storage capacity potential is dependent upon injection rate to a significant degree. Storage efficiency is moderate at around 19%.
D11 – Forties 5 Site 1 Storage Development Plan 10113ETIS-Rep-18-03
The Forties 5 Site 1 is an open saline aquifer CO2 storage development opportunity located some 217km east of St Fergus. The target storage reservoir and containment system is a salt water bearing equivalent of the systems like the Forties and Montrose fields that have successfully held oil and gas in them for many millions of years. Unlike the oil and gas fields, the proposed storage development is an open system and relies upon residual trapping for containment rather than a large structure. These systems represent a significate strategic resource in the North Sea area. The proposed development is a phased one led by injection from an unmanned platform with five wells. Later on, a further site is developed with four additional wells at a subsea template tied back to the central platform. This is likely to be the model for the development of sites with such large areas. The development envisages an injection rate of up to 8MT/yr over a 40 year period. A further appraisal well is recommended to calibrate seismic response so that the seismic tool can be used to refine reservoir quality distribution and trends over a large area. Storage efficiency is typically low in such open systems at 6%. It is acknowledged that lateral containment in open aquifer systems such as this present new challenges to consenting and permitting and that early engagement with regulators will be required.
D12 – Hamilton Storage Development Plan 10113ETIS-Rep-17-03
The Hamilton field is a highly depleted gas field nearing the end of a very successful production lifetime. The timing of the end of field life, its location in the East Irish Sea and is location within 30km of the coast make the Hamilton site an interesting potential CO2 storage opportunity. Whilst injecting into a highly depleted Triassic gas reservoir presents a number of operational challenges, there is the potential for this site to be developed early in the 2020s. An outline plan of a new unmanned platform with 2 active and one spare injection well has been devised to deliver a constant injection rate of 5Mt/yr for 25 years. Operationally this will require the management of a phase transition in the reservoir as the pressure rises. The proposed development has been planned on a new build basis so that the commercial complexities associated with late life asset transfers could be avoided, however there may be some re-use options which might further reduce the cost base. The confidence in the performance of the reservoir under CO2 injection and the ability to retain injected CO2 is significantly enhanced by the oil and gas legacy of the site. As a direct result, no further appraisal drilling is anticipated ahead of any final investment decision. Storage efficiency of such sites is typically very high and expected to be around 70%.
D13 – Captain X Site Storage Development Plan – 10113ETIS-Rep-19-03
The whole Captain aquifer is a large elongate area over 100km long around 100km NE of St Fergus in the Central North Sea. It could potentially accommodate multiple CO2 storage sites. Previous studies by SCCS and others have concluded that the Captain aquifer system as a whole could hold in excess of 360MT of injected CO2 from a range of injection sites. Here, the plan was to design a single practical CO2 injection development that would co-exist with CO2 injection at Goldeneye had the Peterhead CCS project proceeded and also fit with ETI scenarios of CCS build out in the UK. A site selection process considered several potential sites and identified Site X some 40km west of Goldeneye as a prospective location for this study. Targeting the salt water bearing equivalent of the Goldeneye reservoir in the close vicinity of the abandoned Atlantic and Cromarty gas fields offered excellent storage reservoir quality and containment properties and a rich heritage of oil and gas legacy information. This serves to reduce the uncertainties associated with underground characterisation and project performance. A development was designed which deployed a new single unmanned platform, with two active injection wells plus a spare. The unused Atlantic and Cromarty gas export pipeline is a rare candidate for infrastructure re-use and was deployed as part of the development plan. Several well configurations were tested and a plan devised to inject a CO2 supply of 3Mt/yr over 20 years. The Captain X Site is laterally well connected hydraulically with excellent reservoir quality. As with other open aquifer systems the control on lateral migration of CO2 is a key consideration. These factors combine to deliver a typically low storage efficiency for such systems and here is expected to be around 3%.
D14 – Viking A Site Storage Development Plan – 10113ETIS-Rep-21-03
The Viking gas field is a highly depleted gas field in the Southern North Sea (SNS) approximately 90km off the Norfolk Coast and 185km from Barmston on Humberside. Viking is similar to many other gas fields in the SNS and was selected for this study in part because an effective development here would potentially de-risk many other similar sites. Viking covers a large area of many small gas accumulations and so the development here focusses upon Viking A only as an initial phase. It is significantly deeper than Hamilton, and will require heating early in its injection life to manage the phase effectively whilst the reservoir pressure is very low. The planned development comprises a new unmanned platform with two active injection wells and a spare. This would be connected to the Barmston beachhead with a new 185km 20″ pipeline. Injection rates of 5Mt/yr can be sustained for 26 years. No further appraisal drilling is anticipated before a final investment decision. The Viking A site is already well characterised with good reservoir quality and hydraulic connectivity. The caprock sequence includes thick salt deposits which contribute to the high integrity of the location as a site for CO2 storage. Viking A is overlain by a large secondary storage target in Bunter Closure 3 which may present significant further storage upside. The depth and depleted nature of this site contributes to a very high storage efficiency of 78%, almost three times higher than the best saline aquifer systems.
All materials from the Strategic UK CCS Storage Appraisal Project can be accessed here. Readers are advised that the materials are best viewed using Internet Explorer.
Update: On the 9th of June, the Global CCS Institute hosted a webinar on this project, where we provided a more detailed look at the results of this project. To listen to the webinar, click here.
This article was written by Alan James.