Stublach Gas Storage Project, Cheshire

Stublach Gas Storage Project is a salt cavern storage facility currently under development in Northwich, Cheshire, UK. The £500m facility will be one of the largest in the UK, with a total storage capacity of 400 million cubic metres of natural gas when fully operational. It has very high injection and withdrawal rates of up to 33mm³/d.

The project includes the creation of 28 caverns at a depth of 600m in three phases between 2013 and 2018. The first two caverns of the first phase were commissioned in September 2014. The facility is expected to be fully operational by 2020.

GDF Suez unit Storengy is executing the project. The facility is expected to provide security of natural gas supply to the UK.

Stublach gas storage project details

Each of the 28 caverns has a maximum height of 100m and diameter of 100m. The caverns are being created by injecting water into wells drilled for mining. Each well includes a wellhead located 300m apart. The wellheads enable drilling of up to 1km into the salts.

Phase one of the project includes degassing tanks, a pump house, a solution mining facility, water / brine pumps, a nitrogen storage and distribution system, a gas processing plant, a control system and power supply. The solution mining facility is connected to the wellheads through underground steel pipes and cables.

The pump house extracts the brine water solution created during the solution mining process. The brine solution is then passed to the degassing tank where salt and water are separated. This enables the water to be reused.

The gas processing plant includes four gas compressors run by electric drives. The compressors enable transportation of gas to and from the caverns to the UK’s National Grid Transmission System. A drying plant, which separates water from the gas before it is supplied to the NTS, is also part of the gas processing plant.

Construction phases of the £500m facility in Northwich, Cheshire

The project was originally planned to be developed by INEOS Enterprises but was sold to Storengy in August 2007. Construction activities started in October 2008. Since the area is susceptible to flooding, initial works focused on drainage work. The first five of the ten cavern wells were also drilled during this time.

In December 2008, the majority of the brine and water pipelines were installed. Drilling of all ten wells was completed by January 2009.

The construction team handed over the completed facilities to the commissioning team by September 2009. Trial commissioning tests were carried out at the facility during the same time. The solution mining facility of the plant was also completed in 2009 and solution mining of the ten wells commenced.

Development of the next ten caverns of the facility started in October 2010. These caverns are scheduled for completion between 2015 and 2016. Construction of the facility’s gas plant started in 2011.

Contractors with roles in Storengy’s salt cavern storage facility development

Jacobs Engineering Group was contracted to provide engineering procurement and construction management (EPCM) services for the project. Scope of work includes design and installation of the gas compression and treatment facilities, a control system and other utilities.

Costain Oil, Gas and Process won the contract for providing EPCM services for the brine and water facilities of the project. The front-end engineering design (FEED) for the facilities was also carried out by Costain.

Sanderson Watts Associates was subcontracted by Costain for designing degassing tanks for the project. Costain also subcontracted Dew Construction for construction of wellhead structures, access roads, concrete piles and foundations and other works.

Costain unit COGAP contracted Grovemoor Construction to build seven wellheads, a pump house and a degassing tank.

Portastor provided 16 environmentally controlled packaged equipment buildings for the project. The buildings house electrical switchgear, control equipment and other utilities required to operate the facility. The pre-fabricated buildings simplified on-site construction activities.

Hewlett won a £1.6m contract to build the foundations and bases for various process equipment and electrical control cabinets of the facility. J Murphy & Sons was responsible for construction of 15km of underground steel mains under a £2.3m contract. It had previously constructed four drill pads. Early civil works were carried out by A E Yates.

In January 2011, GE Oil & Gas was contracted to supply two compressor units featuring its integrated compressor line (ICL) technology.

Storengy awarded Stadco Cooling a contract for supplying two water cooling systems. In May 2011, ABB won the main automation and instrumentation contract for the facility. A control and administration building was delivered by Brown Electrical under a £175,000 contract. Sheet Piling UK designed and constructed a temporary steel sheet pile trench for construction of the gas treatment plant of the facility.

Long O Donnell Associates provided tender and contract documentation, commercial management and contract negotiation services for the project. A cathodic protection system was supplied by Dutton Contractors. QEM Solutions provided consulting services for the project. A £5m contract for carrying out infrastructure work was awarded to Entrepose Industrial Services.

BAM Nuttal is one of the main civil engineering contractors for the project. Polytech supplied an industrial drainage solution for the facility.