Preflush & Spacer Technology
Preflush and Spacer Technology is a vital part of the cementing process. Without properly designed fluids—both the physical and chemical characteristics—the drilling fluid will not be fully displaced from the hole. This leads to cementing issues regardless of the cement blend selected.
Sanjel Energy Services' many proven spacer systems and standalone products assist with creating specialized solutions to this challenge.
Fresh or saline water creates a barrier between two fluids, but may channel easily due to low density and viscosity.
Typically same blend as lead cement. Will often be in turbulent flow to clean entire annulus through rheology and secondary scouring effect.
Gelled water increases the viscosity of the spacer to effectively push the thinner drilling fluid out of the well or by being able to suspend solid particles. The higher yield point is an indication of how well the fluid can suspend solids.
VISWEEP DM / VISWEEP DM IS
Visweep DM is a powdered spacer that is mixed on-the-fly with Sanjel’s Cyclonic Mixing (SCM) system from a bulk vessel. The spacer’s powder ingredients are bulk blended with the selected weighting material and mixed very similar to a cement slurry.
Visweep DM can be designed to displace both water based and hydrocarbon based drilling fluids. Visweep DM IS includes powdered proprietary chemistry to effectively water-wet the formation and casing surfaces ensuring an effective cement bond.
RP-20 is a silicate-based fluid that coats the formation when it comes in contact with the slurry. It rapidly gels the cement and prevents lost circulation in porous zones and promotes a better cement bond.
SAPP is a traditional mud thinner, but the mud type must be checked to ensure it will be effective. Some new muds will not thin in the presence of SAPP.
Mud flush contains a water-wetting and cleaning surfactant and SAPP. This combination is utilized to clean wellbores that may be old or suspected of having hydrocarbons and/or static drilling fluid present.
INVERT PREFLUSH/ SPACER
The preflush consists of a base oil or hydrocarbon base that may or may not be viscosified along with solvent-surfactant additives to successfully clean and water wet the casing and formation face. The spacer is a gelled water base with another water wetting agent.
WATER WET MAX
Water based fluid meant for displacing non-aqueous or oil based drilling fluids or cleaning oily surfaces in existing wells. Contains no gellant in the package by default.