Coll 30/146 'Oil: Bahrain Petroleum Company: Annual Reports.' [‎207r] (413/767)

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average of 18,614 net barrels.
Consistent with a reduction in the shipment of refined products and the neces
sary curtailment «of Refinery throughput, field production rate was reduced from 20,000 net
barrels per day to 15,000 net barrels per day on September 15, 1941. Towards the end of
December a more favorable shipping schedule was possible and on December 28, 1941, three
days before the end of the year, the field production rate was increased to 18,000 net bar
rels per day.
Routine collection of data indicate continued satisfactory pressure distribution
and pressure maintenance within the reservoir.
Gas Injection:
The injection of Fourth Pay Zone E gas produced through Well No. 51 into First
Pay through Well No. 62 and into Second Pay through Well No. 63 has continued. Evidence
of gas channeling within the First Pay was observed during the early part of the year and
in May the injection rate to that pay was reduced to half its former value. This reduction
in injected volume was effective in combating channeling and also afforded the opportunity
of collecting important data under changed conditions of net fluid withdrawal from the
reservoir.
When the field oil production rate was reduced in September, a corresponding per
centage reduction was made in the gas injection rate into both First and Second Pays in
order to balance the net fluid withdrawal to a volume consistent with our accepted policy
of reservoir pressure and edge water advance control.
Our knowledge of the mechanics of the reservoir has been considerably enhanced
as the result of the opportunity to obtain information under varying conditions.
Edge Water Encroachment:
The daily average water production for the year was 720 barrels compared with a
daily average of 723 barrels during 1940. The reduced rate of oil production during the
latter part of the year is chiefly responsible for this apparent decline although the re
pair of one large water producing well also contributed to this achievement. During the
period when the field produced oil at the rate of 20,000 barrels per day water production
averaged 748 barrels daily and during the period at the reduced oil rate of 15,000 barrels
per day water production averaged 617 barrels daily.
The rate of increase in the percentage of water produced by individual wells has
been maintained at a satisfactory low value by gas injection.
The study of this important problem continues to occupy our attention. Data col
lected during the year have clarified our conception of the mechanics involved and generally
assisted in formulating production policies.