Research On Low Density Slag MTC Technique

Slag MTC technology has the advantages of protecting environment, reducing cost and damage to the reservoir. The compatibility between slag STC cementing fluid and drilling fluid is good, so the cementing quality is improved. The slag MTC technology is gaining widespread attention in cementing industry. In the low-density slag MTC, a large amount of lightening admixture is added, the strength of low-density slag MTC condensate and can not meet the cementing requirements. The development of MTC technology is limited by the brittleness of the condensate. Therefore, this article developed a compound activator which forming a low-density slag MTC recipe. The condensate forming from the new recipe has high compressive strength and certain of toughness. And improve the toughness of low-density slag MTC condensate by compound material.Based on the characteristics of various types of lightening admixture and their synergy with slag, floating beads and micro-silica are selected as lightening admixture. This paper, based on the activating mechanism of inorganic alkaline activator to slag, considering the effect of inorganic alkali to the slag MTC slurry performance, chooses inorganic activator DHM101 as basis, compressive strength and shear strength as target function, and through orthogonal experiment and analysis obtains the optimum combination of all factors, and develops a system of activator suitable for low-density slag MTC. This paper also obtains a low-density slag MTC recipe MC through the optimization of additive. The recipe has the characteristic of good rheological property, low water loss, low free liquid content, good stability, high compressive strength and has certain shear strength. Through theoretical analysis and experimental research, chooses carbon fiber to improve the toughness of low-density slag MTC. The experiment shows that the length of carbon fiber, add-volume and fiber distribution within condensate has a great impact on improving effect; a suitable add-volume should be chose for different length of carbon fiber while improving toughness.