Development and service of drilling fluid


Casing Ø426 mm – 350 m;
Casing Ø324 mm – 3100 m; 
Casing Ø245 mm – 4795 m; 
Liner Ø194 mm – 4695-5755 m;
Casing Ø140/168 mm – 6125 m.

Anniversary 70th well for our company which turned out to be far from simple. It was on conservation for about two years after several unsuccessful attempts to drill an interval of a casing Ø245 mm. Mud services will be provided at three intervals. The most difficult stage will be probably the restoration of the old borehole from a depth of 3100 m and drilling a new one to a depth of 4795 m. This interval is highly weakened due to contact with the flushing fluid that has been in the well for a long time. The drilling of this and the next interval will be carried out with drilling fluid PIDM-2 which has powerful inhibitory properties. While drilling the second interval (4795-5755 m) the solution will be weighted from a density of 1250 kg/m3 to 1460 kg/m3. The drilling-in of the productive horizons will be carried out with the utilization of the P-HKR polymer chlorine-potassium mud, because the bottomhole temperature 150 °C and density of 1,560 kg/m3 impose restrictions on the possibility of the use clay-less biopolymer systems.

The well drilling term – 70 days.
Drilling contractor is Croatian company Crosco - Integrated Drilling & Well Services.