Experimental study on mechanical properties of carbonate rocks under real-time high temperature and heat treatment under triaxial compression
The high temperature and high stress conditions pose great challenges to the efficient exploitation of deep and ultra-deep oil and gas.To investigate the differences in the effects of real-time high temperature and heat treatment on the mechanical properties of reservoir rocks,using a self-designed multi-field coupling test system,real-time high temperature and heat-treated triaxial compression tests were carried out on carbonate rocks in Tarim Oilfield,Xinjiang.Under the two test conditions,the evolution of rock strength,deformation,failure modes,and mechanical parameters were analyzed.The results show that:(1)As the temperature increases,the critical confining pressure of brittle-ductile transformation of carbonate rocks under real-time high temperature decreases,while the critical confining pressure of rocks after heat treatment increases.(2)The elastic modulus of carbonate rock decreases with increasing temperature under both experimental conditions;the Poisson's ratio exhibits different patterns of variation;additionally,the exponential function can be used to describe the elastic modulus and Poisson's ratio at real-time high-temperature.(3)The fracture angle decreases with increasing confining pressure.Compared to room temperature,the fracture angle of rocks exhibits litter variation in real-time temperature,however,there is a trend of increasing after high temperature.(4)Compared to rocks after heat treatment,the influence of real-time temperature on the volumetric strain and dilatancy stress of rock is more obvious.This study contribute to our knowledge of how temperatures affect the mechanical properties of deep carbonate reservoirs under the influence of high temperatures and provide a theoretical basis for the productive and safe extraction of deep oil and gas.
rock mechanicscarbonatemechanical behaviourreal-time high temperaturehigh-temperature treatments
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