METHOD FOR WELL CEMENTATION Russian patent published in 2004 - IPC

FIELD: well boring technology.

SUBSTANCE: a liquid bath made of foaming liquid is placed in the well, volume of foaming liquid large enough to provide for pit-face pressure higher than bed pressure, which is calculated according to formula, and three-phase foam with aeration degree α=2,5-3,0 at volume, providing for filling of well in range from pit face to ceiling of productive bed. Three-phase foam is delivered to pit-face by foaming liquid at volume of drilling pipes and behind-pipe space is then covered. Isolating screen is then formed in area of productive bed by means of pumping of calculated volume of foaming liquid at laminar flow mode until mouth excessive pressure stabilizes, which matches pressure required for breach of isolating screen. Foaming liquid supply is then cut. Mouth pressure is decreased. Casing column is lowered. Buffer fluid is supplied and cementation by cementing solution is performed. Density of cementing liquid, at the moment of end of cementation process, provides for pressure on productive bed, which does not exceed value of pressure required for beginning of breach of isolating screen, according to respective inequality.

EFFECT: preservation of collecting properties of productive layer, higher quality of well cementation with concurrent simplification of technological process.

2 cl, 1 fig, 1 ex