Theory & Application Research Of MTC Technology

Slag MTC cementing system has been extensively concerned owing to its advantage on performance, economically and environmentally. Though the study of MTC slurry has got episodic succeed, but there are still many aspect to be improved, and that restrict its development and popularized. Here is some theory and experiment research for MTC technology.The constitute of mineral slag and bentonite and the change of slag MTC system during different hydration phase was analysed by XRD, as well slag MTC systerm hydration mechanism was studied on the basis of the chemical theory of silicate. During the hydration of slag MTC, cement clinker can be hydrated completely, as a result of the decomposition of vitreum, SiO₂ can be hydrated to active SiO₂ which can also be named [SiO₄]^4- under strong caustic surrounding. The active SiO₂ can be polymerized to tetrahedron which is beneficial to the cementation of MTC slurry congelation; alternately SiO₂ can react with Ca(OH)₂ and get C-S-H gel with low C/S ratio.The experiments shows that compressive strength can be improved by increasing the addition of the mud, the essential constituent of waste mud is similar to the components of the mud which provide theory criteria and emperiment basis. On the solidification of mud cake and the rate of volume contraction of MTC slurry and simulated experiments on the two-interface showed, MTC slurry can be entirely solidified with mud cake; the rate of volume contraction of solidified MTC was far less than the same rate of cement; the interface quality of wellface had less effect on the bonding strength of the MTC solidification. The reason for the low rate of volume contraction of MTC slurry was studied on chemical reaction. How the MTC slurry can improve the second contact surface, including the solidification of mud cake and undisplaceable mud in of two-interface system, and the low contraction rate of MTC slug. The size distribution of slag, micro-silicon and hollow microsphere was analysed by X ray granulometric analyzer, in combination with the theory of close packing and active SiO₂ can improve MTC intensity, the light weight and high intensity MTC slurry system was builded and its theory was completed. The intension of slag MTC congelation was incremental in one year and decreased slowly one year later.Experiments shows that MTC slurry can remain its intensity under high temperature(the peak 160℃) surroundings, which depends on C-S-H gel with low C/S ratio by MTC slurry hydration. The acid resistance and resistance to erosion resulting from Mg²⁺ and [SO₄]^2- can be explained by the alkalescency of C-S-H gel with low C/S ratio.In-situ experiments indicates slag MTC cementing technology can be applied to complicated circumstance, such as long interval isolation, leaky formation and unregular wellbore et al and can improve the cementing quality effectively.