On July 13, 1933 was the beginning of one of the largest fire at a gas well in
the Romanian history. The developing of Copsa Mica gas exploitation led to
decision of Sonametan to drill in 1933 new gas wells (wells 4 and 5). Market
studies conducted by Sonametan stood at decision to supply Sibiu with gas for
consumption. The exploration drilling of well Copsa Mica 005 had the purpose
to explore the Copsa Mica gas dome and to determine by mechanical coring and
electric logging the sequence of layers, their gas content and possibly water.
The drilling of this well started on March 10, 1933 and Rotary drilling system
was used. The first column of 508 mm was fixed at 20.7 meters depth. The
second column of 360 mm was fixed at 109.8 meters. Cementation was executed in
good condition. The drilling continued to the depth of 764.4 m when analyses
indicated a pressure increase in Copsa Mica dome. Gas pressure at the depth of
764 meters was about 100 bars. Given the shallow depth at which these pressures
are encountered, this kind of gas domes pose a great difficulty for drilling.
In order to maintain the layer pressure, during drilling, it was necessary to
use a drilling fluid with a specific weight. Mud was brought from Bazna
to prepare the drilling fluid but in the absence of a special mixer that wasn’t
done properly . That viscous mud quickly gasify. Given the high pressures
encountered as a safety measure and to protect the well in case of eruption the
decision was made on the 24th June, at a depth of 741 meters, to ask The Ministry
the changing of working program by cementing the column immediately. This would
had avoided the formation of a crater next to the wellhead, 17 days later.
Degradation of drilling fluid properties led to increase of gas pression in the
well. At July 11, the pressure reached 50 bars and the gas came out violent at
750 meters north of the well. The pressure in well dropped to 25 bars.
Cementation resisted, or crater would be formed in the well. A huge amount of
sand and marls was projected 100 meters into the air. On
a circular area with a diameter of about 200 meters, the land was covered with
sand and gray marl typical Pontian, white striped calcareous andesitic, tuff,
conglomerate and finally vegetal elements from the valley. The
next morning, the main crater looks roughly elliptical. Next to the main crater
more secondary craters were formed. From the main crater eruption took place
with intermittent bursts which made the impression that earth was boiling. On
the next day, July 13, 1933, at 15.45, after a spark, ignited gas was burning
with a flame height of 100-150 meters. Occasionally violent eruptions took
place throwing masiv amounts of marl and sandstone. The water from the
crater, or after rains formed dark clouds of smoke which sometimes enveloped the
flame. The aim was to stop the eruption by pumping into the well heavy drilling
fluid, but with no results. Pressure in the well decreased and stabilized at 5
bars. The main crater was gradually approaching the well. Similar operations
performed in August, September and October 1933, were unsuccessful. The
material placed in the well was driven by gas, pulverized and thrown up great
distances around the crater. In January 1935, the crater was 205 meters from
the borehole no. 5 and on 9 May, 1935, the crater moved 80 meters towards the well. On August 28, 1935, after a rainfall, the crater again moved towards the well
no. 5 by 45 m reducing the distance between these at 75 meters. In 1940
engineer Popovici had the idea of pumping water into the well. The gas pressure
dropped and led to decrease the flame height from 42 meters to 4 meter. In order to extinguish
the fire there were pumped about 2000 wagons of mud through four 16” pipelines.
The large amount of mud burst into the crater quenching the flames.
Oil well Copsa Mica 005 was spud in 1933 at 764 meters.
Gazeta ilustrata Jul-1933
Gazeta de Transilvania 3-Aug-1933
Longitude and latitude of location: 46.1010991,24.3109354
