Catalogue

Polycem Gypsum composition

Polycem Gypsum composition is a two-component system based on high-strength backfilling gypsum with reinforcing additives and setting retarder.

 

Product specs

Parameter	Standard
Polycem Gypsum composition, component 1
Appearance	White to gray powder
Setting times, min	Initial setting – not earlier than 4.5 Final setting – not later than 20
0.2 mm sieve residue	NMT 1.0
Polycem Gypsum composition, component 2
Appearance	White to yellow powder
рН of 10% aqueous solution	7-9

 

Note. Component 2 is added to the base mix immediately prior to injection into the well. Component 2 consumption is 0.3% w/w to component 1.

 

Application

Polycem Gypsum is used as a backfilling material for elimination of high-intensity lost returns of flush liquids in low-temperature sections and permafrost areas during drilling and workover of oil and gas wells; as well as for eliminating string leaks and restoring the tightness of the cement stone, as well as waterproofing under certain conditions.

 

Treatment

The technology for controlling catastrophic lost returns using Polycem GYPSUM backfilling composition consists in preparation of mixing liquid using a retarder additive in the amount of 3.5-5 kg/m3 depending on the necessary time of the start of thickening.Polycem Gypsum slurry is prepared in a mixing and mediating unit with the W/S ratio = 0,7. After complete mixing, the density of the slurry should be between 1500–1550 kg/m?. The slurry is then pumped through the pipe space to the desired section at equilibrium. Then the tool is raised to a safe depth, and flushing is started in the volume of 2-3 m3, then the well is closed for 3-4 hours for the mixture to harden. After maintenance is completed, the wellbore is flushed and pressure-tested to the pressure expected during further construction, then drilling continues.

 

Packaging

Polycem Gypsum is packed into 25 kg polypropylene bags with polyethylene liner.



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