OS PAYSAL - Reservoir Drill-in Fluid



Reservoir Drill-in Fluid

OS PAYSAL SYSTEM comprises of specially ground and sized, pure Sodium Chloride salt as the main bridging agent, together with optimised levels of water based polymers to provide viscosity (particle suspension) and tight fluid loss control. The viscosifier is high quality Xanthan Gum and the fluid loss polymer is a specially modified polysaccharide intended purely for use in monovalent saturated brines. 


Product Information 

OS PAYSAL comes in a ‘one bag’ form  comprising specially ground and sized, pure Sodium Chloride salt  as the main bridging agent, plus optimised levels of water based polymers to provide viscosity (particle suspension) and tight fluid loss control.


OS PAYSAL is primarily used for temporarily sealing sensitive reservoir formations during well completion and workover procedures with minimum affect on the porosity / permeability of the underlying producing rock structure.


After their application they are removed by back-flowing from the sealed surface with any residue being dissolvable in water or under-saturated brines. This latter part can be done by any water in the production fluids or by introducing a soak / spotting pill as part of the clean-up process.  

OS PAYSAL can be used on its own or with the addition of different sizes of bridging salt particles in the form of OS PAYSAL BLOC I, II and III. How the formulation required is chosen depends on the specific application and down hole condition.


OS PAYSAL is usually mixed in a saturated Sodium Chloride solution thus maintaining the concentration and size of the ground sized salt particles essential for primary bridging.


OS PAYSAL can also be mixed in a number of other brines as long as they are saturated with respect to Sodium Chloride. OS PAYSAL is added to the base brine in concentrations from 40 – 60ppb. In its basic form mixed at 50ppb with a density of 10.5 ppg / 1.25SG it will seal uniform permeabilities up to 10,000 millidarcies and considerably greater when used in conjunction with the OS PAYSAL BLOC products, including micro and mini-fractures.


The weight of the pills can be designed to be within the 10.5 -14ppg range depending on the base brine chosen.



OS PAYSAL can be used for:


  • Reservoir lost circulation
  • Perforation Pills
  • Water soluble Isolation Pills


Although these are the main applications OS PAYSAL can be tailored to customer needs to accommodate each specific set of parameters. These can include:


  • The temporary sealing of sand control screens during completion or workover.
  • Accommodation of high temperatures up to 180°C / 355°F
  • The temporary sealing of casing leaks.



OS PAYSAL is packaged in 50 lb sacks or 25 kg sacks.




Print Print | Sitemap
© Oilfield Supplies & Services Ltd