High-strength low-friction tough cement paste suitable for narrow annular space well cementation of slimming well

The invention relates to high-strength low-friction tough cement paste suitable for narrow annular space well cementation of a slimming well, which comprises the following components in parts by mass: 100 parts of oil well cement, 42-46 parts of fresh water, 1-3 parts of a fluid loss agent, 2-4 parts of a composite flexibilizer, 5-8 parts of a superfine filler, 0.5-1.5 parts of a flow pattern regulator, 0.1-2 parts of a retarder and 0.2-0.5 part of a defoaming agent, and the density of the cement paste is 1.86 g/cm < 3 >-1.90 g/cm < 3 >. The high-strength low-friction tough cement paste has the excellent performance of high strength, small flowing friction, low elastic modulus and the like, can effectively reduce circulating pressure consumption of well cementation cementing construction, and reduces construction pressure and construction safety risks; the mechanical sealing integrity of a shaft cement sheath under the action of a high-frequency alternating load in the staged fracturing transformation process