Preparation method of the microcapsules for low-temperature well cementation to be used to control cement hydration heat

A preparation method of the microcapsules for low-temperature well cementation to be used to control cement hydration heat, comprising the following steps in proper order:

• S1:
• a shell material being weighted with 10-20 g, and added into 50-100 mL of deionized water, then the resultant mixture being stirred in a thermostat water bath at 45° C. so as to completely dissolve it into a homogeneous and stable shell material solution, said shell material being sodium silicate NaSiO3·9H2O;
• S2:
• 10-20 g of a core material and 0.02-0.1 g of an emulsifier being put into a three-necked flask and stirred in a thermostat water bath at 45° C. for 30-60 min so as to uniformly emulsify and disperse them, forming a stable oil-in-water core material emulsion, while adjusting the pH value of said emulsion to descend below 5.5 with a pH adjuster, where said core material is a binary composite phase-change material prepared by n-decanoic acid and lauryl alcohol, the preparation process of said binary composite phase-change material includes mixing n-decanoic acid with lauryl alcohol by mass ratio of 1:1, and stirring them evenly;
• said emulsifier is a mixture of alkylphenol polyoxyethylene ether-10 and cetyl trimethyl ammonium bromide, the mass ratio of the cetyl trimethyl ammonium bromide is 20-80%;
• S3:
• said three-necked flask containing said core material emulsion being transferred to a water bath at 50-90° C., and then said shell material solution being dropwise added into it with stirring, after reacting for 2-3 hours, a solid-liquid mixture being poured out so as to naturally cool it to room temperature, thus said cooled solid-liquid mixture being processed by suction filtration, washed with ethanol and deionized water, respectively, to remove impurities, and finally being processed by freeze-drying.