Company: EnQuest

Project: Thistle Alpha Late Life Extension

Location: North Sea, UKCS


PEAK has been involved from the beginning in the conceptualisation and implementation of a process simplification and late life extension project on a first generation platform in the North Sea, which commenced production in the mid 1970s.

There are presently eighteen producing wells and seven water injection wells producing at a rate of circa 5,000bpd. The field economics were becoming increasingly unattractive, with high OPEX (Operating Expenditure) due to maintenance, large PoB, reduced production and platform availability, that the differential between lifting costs and revenue were likely to result in cessation of production by 2015, without significant intervention.

In 2013, a major program of work to extend the life of the platform was initiated, commencing a late life extension programme of facility refurbishment, with the centrepiece of a strategy to recover a further 35 million barrels of oil from the field.

The first phase of the programme took the form of a successful rig reactivation project. Over the past three years, the installation has successfully completed the first phase of drilling, completing five new wells including three with electric submersible pumps, well workovers and partial well abandonments that restored production figures to 1990s levels of performance. In 2014 a second drilling campaign will target new wells, workovers and well reinstatements that will significantly extend the life of the field.


Since the conceptual phase, PEAK has provided on-going support to the operator within their own organisation, as well as the provision of process engineers within the main EPC contractor, as well as the detailed process and technical safety design of the produced water and utility systems.

Other elements of the programme included a process simplification exercise to create a fit-for-purpose plant environment, a new process control and safety system, topsides integrity work, and structure-focused workscopes to maintain the jacket integrity of the asset. The latter stages of the programme were significantly bolstered in early 2013 when it was announced that EnQuest had secured a brownfield tax allowance in support of its plans to maximise recovery from Thistle. EnQuest is among the first operators to secure the allowance, which is one of a series of UK Government measures aimed at stimulating growth in the North Sea, and enables the business to commit fully to a new phase of investment.


PEAK’s involvement has allowed the operator to significantly reduce the OPEX of their facility, improving the production lift costs down to industry targets of less than $10 per barrel. This represents a complete turnaround for a platform, which in its latter years under other operatorship, was being managed with a view to production ceasing. The continued operation of the facility has been secured for a further 15 years. Thistle LLX involved a programme of coordinated enhancements to the infrastructure and to key systems. The first major element of this programme saw the successful installation of a new power generation turbine and local equipment room, significantly enhancing power supply in terms of capacity and reliability. The installation and heavy lift required careful planning and was flawlessly executed by a team who demonstrated many EnQuest values, such as agility, collaboration and creativity.

Additionally, PEAK’s provision of high quality principal process engineers to conduct continued involvement ensures that the asset is re-designed and operated to optimise reservoir recovery at minimal cost. Process simplification and debottlenecking of all topside systems to was also completed to achieve new production profile.