RE: 2P reserves, Worcester wells, etc.12 Sep 2020 21:17
Bressay info. This field has the heaviest oil (110-120 API, 1000 cp
in situ oil viscosity) of all the fields discussed so far. It is in the
Hermod and Dornoch sands in the Sele formation, with about
265 ft maximum oil column, a small gas cap, and a potentially
large and effective aquifer. Fig. 12 shows the top structure
map. The permeability is in the 10 darcy range. Four
conventional appraisal wells have been drilled in the
formation. DSTs conducted in these, with ESPs for artificial
lift, had flowrates ranging from 200 to 2800 BOPD.
The thrust has been to demonstrate that an economic
development can be achieved with a cold water flood as the
baseline scheme. Simulation studies have considered long
(6000 ft) horizontal wells, bilateral wells and trilateral wells,
with water injection to ensure 100 % voidage replacement
from the outset. Well spacings from 30 to 60 acres have been
tried. It has been highlighted that the frictional losses along the
long horizontal wellbore is a factor to consider in the design of
the scheme. A further appraisal well or two need to be drilled,
and an EWT, on similar lines to those conducted in the fields discussed above, needs to be carried out, before sufficient confidence can be gained, to proceed to a development.
A range of tertiary recovery techniques have been
simulated with Bressay. These are the injection of polymer, hot
water injection, gas injection, steam injection and in-situ
combustion. Steam injection gave the highest recovery, while
in-situ combustion came next.
Bit of work still to do if tie back to Kraken is the best option. Definitely need to drill a few more wells in hot spots to make it worth while. No rush imv. If Enquest can use their experience to evaluate the data again and drill another set of wells with better flow rates, it could be worthwhile.