The advanced dispersive type high temperature filtrate reducer used in oil well cement was synthesized with 2-acryloyl-2-methyl-propyl sulfonic (AMPS) , N, N-dimethylacrylamide (DMAA) and organic acids. When the mass fraction of synthetic filtrate reducer was 1%, the filter loss of the cement slurry was 30ml/30min at 120 °C and 49ml/30min at 150°C respectively, and the cement strength was 25MPa after 24 hours, and the rheological property of the cement slurry was well when the mass fraction of synthetic filtrate reducer was 2%, and liquidity factor was 0.85, and the consistency was 0.43. The results showed that the filtrate reducer had good dispersity and could control the fluid loss efficiently, and the ability of resistance to high temperature and salt resistance was good.

With the demand of improving the second interfacial bonding strength and environmental protection, MTC cementing technology has obvious technical and economic advantages. However, due to containing lots of low-density materials and slurry treating agents, which make low strength, the application of low-density slag MTC cementing slurry system is restricted in the cementing of deep wells and low-pressure leakiness formations. According to the theory of particle distribution and based on particle size analysis of floating bead, micro silicon and slag, solid-phase proportioning design of low-density (1.35~1.55 g/cm3) slag MTC was carried out in this paper. By adjusting the adding amount of micro silicon and activators, the slag MTC cementing fluid system with the 24-hour compressive strength greater than 21.6MPa which has the density range of 1.35 to 1.55g/cm3 was get. This system has small initial consistency, short thickening transition time, low water loss and good rheological property. And at last, the mechanism of improving the strength of low-density slag MTC cementing fluid system was analyzed.