Bentonite based mud may be used to impart stability to boreholes through soft seabed sediments prior to running structural or conductor casing. 30-40ppb bentonite mud shall be used offshore to sweep top hole while drilling and to spot on bottom prior to running surface casing.
1. Flush tank and lines with drill water.
2. Fill the surface tank to 75 %of capacity with drill water.
3. Check chloride concentration to ensure no sea water contamination. CHECK calcium and magnesium ion concentrations.
4. Add soda ash . . .