Column closed interval 5388-4009 m, including Visean productive horizons.
When drilling interval used clayless biopolymer mud BIOCAR-MT.
PARAMETERS OF DRILLING MUD BIOCAR-MT:
- Funnel viscosity – 100-115 s;
- Density– 1,27-1,28 g/cm3;
- Gel– 57/65 dPa;
- Plastic viscosity – 25-30 mPa*с,
- YP– 220-240 dPa,
- Filtration loss– 3-3,5 cm3/30 min.;
- Mud Cake Friction Coefficient – 0,11-0,12;
- Salinity – 16,5-17,5%;
- Concentration of KCl - 7-9%;
- рН – 8,0-9,0.
The objective of further drilling to a depth of 5941 m is a showdown Tournaisian deposits with abnormally high reservoir pressures. Expected mud density 1540-1560 kg/m3.
High reservoir temperature at a depth of design (150°C) excludes the use of weighted mud clay-free polysaccharide based. In this regard, at the opening Tournaisian deposits will be used polymer clay washing system - similar to that employed previously, in liquidation of showings of gas and drilling with AHFP at Poltava.
The transition to a new type of drilling mud will be held at the end of the WOC casing.
