CPC C09K 8/467 (2013.01) [E21B 33/14 (2013.01)] | 13 Claims |
1. A well cementing method for improving cementing quality of a well, comprising: controlling the hydration heat of cement slurry to control the degree and rate of hydration heat release from the cement slurry, wherein
the method improves the hydration heat release during formation of cement with curing of cement slurry, improves the binding quality between the cement and the interfaces, and in turn improves the cementing quality at an overlap section of a well;
wherein when the controlling is achieved the cementing quality at the overlap section is improved;
wherein lowering the degree of hydration heat release from cement slurry is achieved by reducing the addition amount of a material generating a high hydration heat;
wherein lowering the rate of hydration heat release from cement slurry is achieved by adding a retarder;
wherein the well cementing is performed on a short-overlap-section well having a length of the overlap section not greater than 150 m; wherein
for well cementing with a separable setting cement slurry comprising a lead slurry and a tail slurry, wherein for the lead slurry, controlling of hydration heat is achieved by lowering the degree and rate of hydration heat release from the slurry, wherein the lead slurry is cement slurry with high strength and low elastic modulus, and its additional safety time for thickening is 60-300 minutes; and wherein for the tail slurry, controlling of hydration heat is achieved by increasing the degree and rate of hydration heat release from the slurry, wherein the tail slurry is cement slurry with high strength, and its additional safety time for thickening is 30-60 minutes;
wherein the high strength occurs when the 7-day strength is greater than 28 MPa, and the low elastic modulus occurs when the elastic modulus is less than 10 GPa.
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