This test may be used for determination of Chloride content in both fresh and salt water muds. The Chloride level must be maintained at the level specified in the drilling fluids programme. Reporting Freshwater and Saltwater Muds: mg/l Cl– +/- 10 Sources of Error Silver Nitrate has a limited shelf life and must be kept … Chlorides – Water Based Mud Testing
Design and operating principles can be found in suppliers literature. The decanting centrifuge consists of a rotating horizontal centrifuge bowl with a conveyor turning in the same direction but at a lower speed. The slurry is introduced at the centre of the narrow end of the bowl and travels to the liquid overflow at the … Solids Control Equipment – Centrifuges
The correct selection, engineering and maintenance of drilling fluids is critical to the success of the drilling operations. Each member of the rig team must understand their responsibilities to ensure: the work required to mix and/or treat the drilling fluids is carried out safely and economically any discharges are handled in an environmentally responsible manner … Drilling Fluids Responsibilities
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
For the calculations the following parameters have been used: 26in and 16in holes: MW 9.3ppg, PV 4, YP 10 12.1/4in and 8.1/2in holes: MW 10 ppg, PV 8, YP 11 9.1/2in drill collars have been used in the 12.1/4in section For jet selection it has been taken into consideration that lost circulation is frequently occurring … Example Hydraulic Optimisation Programme
A successful Barites plug should accomplish: killing of the well plugging of lost circulation zone. Application Barite plugs shall be applied when the following situations arise: Simultaneous kicking and lost circulation. Abandonment procedure to allow safe withdrawal of drillpipe to permit subsequent setting of a cement plug. Withdrawal of drillpipe to either set casing or … Drilling Fluids Losses: Barites Plugs
The following table presents the main contaminants and the chemical treatment to be used. CONTAMINANT CONTAMINANT ION TREATMENT CHEMICAL CONCENTRATION PER 100 ppm CONTAMINANT Gypsum or Anhydrite Calcium (Ca ++) Soda ash if pH okay Sodium bicarbonate if pH too high 0.1 lb/bbl 0.15 lb/bbl Cement Calcium (Ca ++) Hydroxide (OH) Sodium bicarbonate 0.15 … Summary Treatment of Mud Contaminants
Contamination with Calcium Sulphate (Anhydrite) will result in flocculation of bentonite muds resulting in an increase in yield point, gel strengths and fluid loss. Polymer muds are relatively insensitive to this type of contamination, unless significant quantities of drilled clay solids are present. Sources of Contamination This type of contamination can occur whilst drilling Anhydrite. … Drilling Fluid Contamination: Calcium Sulphate (Anhydrite)
Mud weight is of the utmost importance to the safety of the drilling operation. The mud gradient must be controlled at the programmed value or at the value determined by the Drilling Supervisor, to ensure integrity of the hole and safety of personnel on board the rig. Equipment Normal Bariod mud balance shall be used … Mud Gradient – Mud Testing