Application of grout slurries with the defecate addition for effective well cementing
Purpose. Research and substantiating the expediency of cement mix formulations of grout slurries with different Defecate additive content and their effective use when cementing the reservoirs prone to absorption of the cement slurry, as well as to prevent behind-the-casing flows and for cementing operations in the zone of abnormal pressures (hydraulic seam fracturing). Methods. Analytical and experimental studies of the physical-chemical grout slurry properties are used: determining the influence of the Defecate additive content on the cement mixture technological properties; study of a change in the grout slurry rheological characteristics at various temperature conditions; testing the formulation of grout slurry with different rates of strength development; substantiating the economic efficiency of using the grout mixtures with the Defecate additive. Findings. It has been revealed that the cement mixture fluidity increases by 10-20% with the addition of a Defecate in the proportion of 5-20%. With a further increase in the Defecate content, the stone strength deteriorates, and with a decrease, the grout slurry concentration increases. It has been found that when Defecate is added to the cement mixture in a proportion of 20%, the pumpability of the cement slurry doubles, that is, from 1.5 to 3 hours. The economic efficiency has been proved of using these mixtures during insulating activities in the well No. 122 of the Kulychykhynske NHKR (oil and gas condensate field). The improved formulations of grout slurry with the addition of a Defecate are recommended to be used during repair-insulation works for delimitation of producing reservoirs prone to absorption, behind-the-casing flows and hydraulic fracturing. Originality.New dependences have been determined of the technological and rheological characteristics of grout slurries on the content of the Defecate additive, which makes it possible to set its optimal proportion. Practical implications. The use of grout mixture based on the Defecate will expand the raw material base for obtaining lightweight grout slurries. The properties of such a solution make it possible to use a grout mixture for cementing wells in the zone of abnormal pressures, while reducing the costs for the process of reservoir delimitation. Keywords: well, behind-the-casing flows, producing reservoir, grout slurry, Defecate