Salinity issue forces temporary production cuts from North Sea Blythe, Elgood wells


Overseas staff

LONDON – IOG continues to experience start-up problems with its Saturn Banks gas project in the UK’s southern North Sea, which came online earlier this year.

Early last month, aqueous liquids from the Blythe and Elgood wells began arriving at Saturn Banks receiving facilities in Bacton, Norfolk. These fluids include water and monoethylene glycol (MEG), the latter of which is intended for use in a closed-loop system to inhibit free water and prevent the formation of hydrates in the pipeline.

It is injected into the Blythe and Elgood wells as an MEG/water mixture, recovered in Bacton, then regenerated and returned offshore to be reinjected into the wells.

Water volume and salinity levels have been higher than expected, with the salinity of returned fluids currently being above the maximum allowed for processing at Bacton. To prevent these high salinity fluids from contaminating other MEG users at the terminal, an alternate regime of discontinuous slugcatcher liquid unloading is in place.

These issues forced IOG to reduce production to 30 MMcf/d to isolate the source of produced water. Tests are underway, which require turning off Blythe or Elgood for periods of time.

At the moment, an alternative treatment or replenishment regime is required, with a storage capacity of approximately 3,000 cu. m and an escape route both established for aqueous fluids. IOG is currently evaluating treatment options to confirm the most economical future operating regime.

At the Southwark field, under development in license P1915, the company is targeting first gas in the fourth quarter. The final closure spools for the pipeline and the dewatering of the pipeline will both be completed during the final DSV campaign, which is due to begin next month.

The jackup Noble Hans Deul resumed drilling of the Southwark A1 (West) well in July. Progress to date has been hampered by drilling fluid losses, the magnitude of which has led to long periods of non-productive time.

Upon completion of the well, A1 and A2 will undergo hydraulic stimulation prior to commissioning. In parallel, various changes to the Southwark platform will take place, based on operating experience to date on the Blythe platform.



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