Tournaisian perspective deposits with abnormally low formation pressure were entered for the first time by this well. Formation temperature – over 150⁰C. The drilling intervals were complicated by rocks with low stability. There was a clear dependence of a caving intensity from a mud density. The drilling was run through the use of the weighted polymer-clay drilling fluid SWDM.
PARAMETERS OF SWDM DRILLING FLUID BEFORE LINER RUNNING:
- Density – 1,61-1,62 g/сm3;
- Funnel Viscosity – 80-100 s;
- Gel – 70/80-80/90 dPa;
- PV – 50-55 mPa*s,
- YP – 200-260 dPа,
- Filtration loss – 5,0-5,5 сm3/30 min.;
- Mud Cake Friction Coefficient – 0,14-0,15;
- КСl – 6,0-8,0%;
- Salinity – 17-18%;
- рН – 8,5-9,0.
