Experimental Investigation on the Evolution of Tensile Mechanical Behavior of Cement Stone Considering the Variation of Burial Depth

The cement sheath is an annular structure between casing and formation, which crucial to the integrity of wellbore system. Considering that temperature pressure environment changing continuously with increasing burial depth, micro-structure macro=mechanical properties in-situ will change accordingly. To investigate variation depth on evolution tensile mechanical behavior oil stone, five temperature-pressure curing testing conditions (25 °C—0 MPa, 50 °C—10 80 °C—20 110 °C—30 140 °C—40 MPa) are set approximately simulate in situ at typical depths (0 m, 1000 2000 3000 4000 m). behavior, pore size distribution stones each condition tested comparatively analyzed. Results show pressure, brittleness stone reduces its ductility strengthens strength experiences rapid growth first, then increases a slower rate finally decreases. failure mode gradually transforms from splitting tensile-shear composite fracture, accompanied by fracture surface roughness. Microscopically, closely stacked laminated sheets interconnected fiber networks. dense becomes loose porous. porosity also 15.96% 29.46%.