Abstract

F3-FA field is a small offshore gas field in the Dutch sector of the Southern North Sea. The discovery well drilled in 1971 located rich gas in the Jurassic Scruff Greensand Formation. Its constrained size meant field appraisal did not take place for a further decade with two wells drilled in 1982.

Following appraisal, the field struggled to compete for investment capital against other development opportunities and also for pipeline access. Ultimately the original operator exited the field in 2008 - Centrica Energy purchased its equity and field operatorship.

A different opportunity set allowed Centrica and its partner EBN to advance the field development. Uncertainty regarding the dynamic performance of the field and a recognition of limited volumes and therefore producing field life led to the adoption of a Self-Installing Platform (SIP). The platform is a first of its kind at this scale, being the largest mobile production gas platform, 133 meters high and slightly heavier than the Eiffel Tower and designed for re-use on another location to produce some other small accumulation.

The platform was installed in 2010 with full processing and compression facilities in place, tied into the NOGAT pipeline system. Production is from a single, near-horizontal production well. The reliance on a single development well reflected the marginal nature of the development with a range of reserves that reflected uncertainty about the dynamic behaviour of the reservoir that did not have the luxury of any analogues to draw on.

First production was achieved in 2011 and to date the field has performed strongly with no indication of aquifer influx which was an uncertainty going into development. Condensate yield proved much higher than anticipated.

The prolonged time between exploration and first production is a familiar trait for many small developments of recent years in the Southern North Sea, often executed by a new breed of operator. It is also typical of the choices needed to bring such fields to production given modest reserves and unresolvable subsurface uncertainties.

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