METHOD TO PREVENT GAS FLOW VIA ANNULUS DURING WELL CEMENTING

摘要

FIELD: oil and gas production, particularly methods or devices for cementing, for plugging holes, crevices, or the like.;SUBSTANCE: method involves securing casing pipes by cementing thereof with cement mortar up to level located over productive reservoir roof; arranging composition having viscoelastic properties over cement mortar; placing plugging composition having setting time exceeding that of cement mortar over viscoelastic composition, wherein the plugging composition has density providing creation of hydrostatic pressure exceeding gas pressure in productive reservoir before hardening of cement mortar supplied within productive reservoir interval. Viscoelastic composition is poured so that viscoelastic composition height is not less than 10 m. The viscoelastic composition is clayless viscoelastic composition.;EFFECT: increased cementing reliability.;4 cl, 1 ex