VISCOELASTIC STRUCTURE FOR ISOLATION OF THE INTERSTRUCTION SPACE OF WELLS Russian patent published in 2017 - IPC E21B33/138 C09K8/508 

FIELD: chemistry.

SUBSTANCE: invention relates to viscoelastic compositions (VEC) used to prevent intercolumnic gas manifestations and to isolate the intertube space of wells during the primary cementing of casing strings run in intervals of permafrost (PF). Viscoelastic composition contains 64.0 - 68.0 parts by weight. Barite, 1.0-5.0 parts by weight. Bentonite clay powder, 0.3 - 0.7 wt p of xanthan gum and 90.0 to 160.0 wt p of water. The composition further comprises 8.0 to 12.0 wt p of filler in the form of hollow glass microspheres with a particle size of 200 to 400 mcm, 0.3 to 0.7 wt p of carboxymethyl cellulose as a fluid loss reducer, 8.0 to 12.0 wt p of calcium chloride as an anti-freezing agent and 8.0 to 12.0 wt p of silicon dioxide as an anti-tracer.

EFFECT: increasing the efficiency of injecting the viscoelastic composition into the annulus of wells and pumping into the well during the cementing of the casing in one operation without additional work on pumping the composition into the annular space from the wellhead.

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