METHOD OF PREPARING WELLS TO CEMENTATION Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: method relates to drilling of oil and gas wells. According to method, installed in bottom-hole of well is bath containing mixture of water solution of sodium metasilicate with ether of cellulose. After that, successively injected are following chemicals: viscous-resilient separating agent, loosening compound, waterproofing and stabilizing compound, and sedimentation compound. Used in function of viscous-resilient compound is compound containing following components: reagent-polysaccharide 1.0-5.0%, complexing agent 0.15-2.0%, weighting agent 1.0-30.0%, water - the balance. Used in function of sedimentation compound is compound containing following components: cement 100 m.p., oxyethylcellulos 0.3-0.4 m.p., water 164-174 m.p. Application of aforesaid method and materials improves quality of preparing well to cementation drilled with washing by solution of any type. This is achieved due to increased degree of replacement of drilling mud with viscous-resilient separating agent, reduced permeability of filtration crust and increasing its stability to cement slurry with simultaneous enhancing its chemical affinity with respect to cement, and also due to reduced negative influence of buffer liquids and cement slurry on productive capacity of well. EFFECT: higher efficiency. 4 cl, 3 tbl