These mud systems are used both onshore and offshore to drill the 12.1/4in hole.  This type of mud is run without the use of thinners, provided the solids content (less gravity solids) of the mud is kept within the desired range. They tend to be run with inverted rheology where the YP is greater than … Low Solids Non Dispersed Mud

Sea Water/ Bentonite is a simple mud system for top hole drilling. Viscous bentonite slugs pumped regularly for good hole cleaning. Returns are not be taken to surface during conductor pipe cleaning/ under-reaming; ports in the conductor pipe can be used to minimise the hydrostatic head. These sections can be successfully and economically drilled with … Sea Water/ Flocculated Bentonite Slugs Mud

This mud system is used to drill the reservoir section in onshore and offshore wells.  It is a sodium chloride based system, which gives inhibitions with minimal formation damage. It is beneficial if the solids content is kept as low as possible and carrying capacity to the optimum.

Although gel/polymer muds are normally prepared as fresh water drilling fluid systems, existing bentonite spud mud or native clay mud may be converted simply by diluting the systems and adding the appropriate fluid loss polymers. The success of any conversion operation will depend on the solids content of the mud. If the solids content is … Gel/Polymer Mud

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. Bentonite Pre-hydration 1. Flush tank and lines with drill water. … Bentonite Mud

Reservoir sections can be drilled with a low colloidal content sodium chloride/polymer mud system weighted with calcium carbonate. The recommended formulation is to minimise formation in a sandstone reservoir. Product Functions CACO3 Acid soluble weighting agent. SODIUM CHLORIDE To improve shale inhibition. IDVIS A pure grade xanthan gum, for providing yield point and progressive gel … NaCl Polymer CaCO3 Mud

Surface sections can be drilled with a gypsum/polymer water based mud. Attention must be paid to preserving the inhibitive properties of the drilling fluid by maintaining appropriate polymer and gypsum concentrations in the mud. Particular attention must be given to solids control by optimising the operation of the solids control equipment in order to minimise … Gypsum/ Polymer Mud