EXPERIENCE OF RESEARCHES OF CEMENT BASED MATERIALS FOR STEAM INJECTION WELL CEMENTING

Abstract

He article discusses the experience in the development and use of cement materials for steam injection wells. To use the technology of injecting steam into the well, it is necessary to use special cements, the stone of which does not reduce strength when exposed to high temperatures, i.e. it is resistant to thermal stress. A feature of steam injection wells is low initial temperatures, which subsequently rise to 200 - 350 °С. A review of foreign and domestic studies on the development of cement compositions for fastening steam injection wells is presented. As a rule, the materials used for cementing wells were obtained on the basis of Portland cement with the addition of siliceous components, providing a C/S ratio of 1.0. Foreign methods provided for a complete simulation of the conditions for the samples to be in the well, namely, a long (up to 4 weeks) exposure of the samples at normal temperature, followed by heating samples to the test temperature, holding at this temperature for 1 - 6 months and then slow cooling. The methods adopted in Russia suggest a significant reduction in each research cycle by reducing the time of hydrothermal exposure. Unfortunately, this does not allow one to obtain completely thermostable phases that are not subsequently subjected to phase transitions. Control of the results was carried out according to the results of mechanical tests and ultrasonic strength analysis. Both in the results of foreign and Russian studies, there was a significant discrepancy in the data obtained by various methods. The results presented in the article showed that the most informative and reliable are the results of direct mechanical tests, which exclude errors in ultrasonic research methods that occur at temperatures above 100 °С.