Experimental study on the thermal damage characteristics of cement stone

Aiming at the problem of cement ring sealing failure during deep high temperature shale gas exploitation, comprehensively considering influence characteristics multi-cluster fracturing multiple horizontal wells and formation temperature, cementing southwest region is taken as research object. After exposure to different temperatures (95?C 135?C) for times (5, 10, 20 times), axial triaxial tests with confining pressures (0, 5 MPa, 15 30 MPa) were carried out. The shows that: stress-strain curve stone after heat treatment can be divided into four stages: compaction, elastic, yield, post-peak stage; pressure increases, compaction phase disappears, yield we see transition from brittle ideal plasticity peak number thermal cycles increase, cohesive force decreases significantly, internal friction angle a slight increase. elastic modulus strength decreased.