Влияние микрокремнезема на физические свойства тампонажного камня

Abstract

The aim of the study has been to define the changes in the physical-mechanical properties of cement stone when adding different-concentration silica fume (SF) of different grades, and to experimentally compare the obtained values with the state standard (GOST) permissible values. Different-concentration cement slurry was mixed, with a 48-hour interval for thickening and solidification before the test. The obtained cement stone was tested for compressive and flexural strength using a hydraulic press; besides, its water separation and spreadability measurements were taken. Based on the experimental data analysis, the dependence of the cement stone’s strength properties on silica fume admixture was defined, and conclusions were drawn on the permissible amount of SF in the cement slurry. With the SF concentration exceeding 8%, the cement slurry no longer meets the standard values and becomes low workable and highly viscous. The article discusses the possibility of improving the cement stone properties in well construction for hydrocarbon deposits development. A series of experiments have been carried out with the purpose to modify the cement of PCT - 1-50 grade with silica fume admixtures of MK-65 and MK-85 grades. The reagent was chosen due to its ability to influence the strength and permeability of the cement stone, as well as the water separation, sulfate resistance, and density of the cement slurry. On the basis of the study done, it has been concluded that the above admixtures do influence the strength properties of the stone; though to increase the flowability of the cement slurry, further experiments are needed. A properly selected admixture can reduce the cement slurry’s viscosity, thereby making it possible to achieve the consistency meeting the production requirements.