From previous studies it was concluded
that the impairment of gas production by
salt precipitation is localised in the near
well-bore region and perforations, and
not deep in the reservoir (at least for the
particular field studied in combination
with the production age of the field).
Main indicators of this are: 1) Salt
particles accumulating in the well bore and
up-hole, that are believed to originate from
salt water produced at the perforations
and not from salt particles transported in
the pores. 2) The fact that production (at
first instance) can be restored with a fresh
water soak using relatively small amounts
of water and relatively short soaking times
(small penetration depth).
For a production environment, a relatively
simple model is required, which predicts in
a quantitative manner the following
- The onset and speed of production
decline (boiling down to a prediction
of the amount and location of salt
precipitation and the subsequent
effect on transport properties, that
is permeability and capillary pressure
- The relation between fresh water soak
volume and washing frequency on
production recoverage (boiling down
to a prediction of speed and extent of
water saturation and salt dissolution
during fresh water soak, and subsequent
water back production).
Phase 1 – Salt precipitation predictions
with existing reservoir models – FINISHED.
Phase 2: To develop precipitation and
water wash models and validate on field
data, using multi-scale model approach.
Phase 3: To develop on-line monitoring
& optimisation functionality for Short Term
(Real-Time) Production Optimisation.
Phase 4 – To develop an off-line tool
for Field Development Planning.