Chevron starts polymer injection
at Captain in North Sea
Late last year, Chevron committed to the application of polymer technology to enhance oil recovery from the Captain field in the UK central North Sea. The first-phase program, which follows various enhanced oil recovery (EOR) pilot trials
at the field since 2010, is an expansion within
the existing platform area, with five long-reach
horizontal polymer injection wells planned.
Captain, discovered in 1977 in block 13/22a
close to the Outer Moray Firth off northeast
Scotland, is a billion-barrel field which began
producing in March 1997. The production facilities comprise a wellhead protector platform
and a bridge-linked platform connected to an
FPSO vessel. The complexity of the reser voir
and the relatively heavy crude have over the
years necessitated extensive horizontal drilling, waterflood, and installation of downhole
electric submersible pumps.
Britain’s Oil & Gas Authority (OGA) is keen
to promote wider use of polymer technology in
the wider North Sea area, as part of its remit
to maximize the UK’s remaining offshore oil
and gas resources. Chevron was one of the
leading contributors to the OGA’s recently
published document, Polymer Enhanced Oil
Recovery – Industry Lessons Learned.
Colin Freeland, Captain EOR Project Manager at Chevron, explained the background to
the project and the goals for the stage 1 program.
Offshore: For the phase 1 Captain EOR proj-
ect, Chevron is applying a synthetic HPAM
(partly hydrolyzed polyacrymalide) polymer.
What are the beneficial properties of this
polymer, and has it been used successfully
on other heavy-oil field projects?
Freeland: Polymer is introduced to the
injection water stream to increase the viscosity of the injected fluids. By doing this, the
mobility ratio between the Captain oil and the
injected fluid is reduced, leading to higher
recovery. Other heavy-oil fields have used
similar technology, however, this is the first
major deployment of its type in the North Sea.
Offshore: Has it had to be adapted in any
way to suit Captain’s needs?
Freeland: The polymer is procured as a liq-
uid emulsion rather than a powder for offshore
use and to enable this Chevron has entered
into collaborations with polymer vendors to
optimize their products for use in Captain.
This collaboration has delivered a significant
improvement over industry standard HPAM
emulsions and we are now able to deploy the
polymer with single stage mixing which is a
more simple and cost effective method.
Of fshore: What trials did the company run
on this or alternative polymer formulations
before committing to its use at Captain?
Freeland: Chevron runs a series of laboratory tests and yard trials before determining
whether a polymer would be suitable for the
Of fshore: What is the extent of the current
waterflood operation on the field, and will this
continue, or be scaled back?
Freeland: The Captain field is under full
waterflood development. For stage 1 of the
Captain EOR project, the plan is to start up
five polymer injection wells between 2017 and
2021. All other areas of the field will continue
under waterflood and are subject to potential
future EOR expansion.
Offshore: How many Chevron personnel
are working on this project, both in Aberdeen
and elsewhere, and which other companies
Freeland: There are 25 Chevron personnel
working on the project team currently. We
also rely on assistance from other company
resources including Captain asset personnel,
support staff in Chevron’s Upstream Europe
The Captain production complex in the UK central North
Sea. (Images courtesy Chevron)