Low-temperature cementing slurry system and composition thereof

The present invention provides a low-temperature cementing slurry system. The slurry system has the characteristics of low density, low temperature early strength and low water loss, and has performances such as thickening time and compressive strength meeting the requirements of deepwater cementing construction site. The low-temperature cementing slurry system comprises the following components by weight: 100 parts of oil well cement, 62-175 parts oil well superfine cement, 7.3-23 parts of nano-silica, 10-32 parts active calcium silicate, 15-50 parts of hollow glass microballoon, 3.6-10 parts of an early strength agent, 3.2-8.6 parts of a fluid loss agent, 0.8-2.0 parts of a dispersing agent and 120-195 parts of water. The low-temperature cementing slurry system has density between 1.30-1.60 g/cm , and is particularly suitable for cementing operations on a deepwater low-temperature surface casing segment. The invention has important significance in reducing the offshore cementing cost, and offshore oil and gas resource exploitation.