钙基晶须自修复剂对CCUS井固井水泥石裂缝自修复的影响OA

In wells for carbon capture,utilization and storage(CCUS),cement sheaths are easy to get chemically damaged,hence reducing their service life.A study was conducted to enhance the self-healing capacity of cement sheaths by reacting calcium-based whisker self-healing agent with CO2 to produce CaCO3.The influence of calcium-based whisker self-healing agent on the self-healing process of cement sheaths was studied using mechanical tester,X-ray diffractometer(XRD),thermogravimetric analyzer(TGA),scanning electron microscope(SEM)and industrial computed tomography(CT)etc.The results of mechanical performance tests showed that after 28 days of self-healing,the self-healing rate of the compressive strength of the set cement incorporated with the calcium-based whisker reached 83.87%,which is 90.31%higher than that of the set cement without incorporating calcium-based whisker.Phase analysis and SEM observation results show that a large number of calcite-type calcium carbonate crystals were generated around the self-healing material and deposited in the cracks of the set cement,thereby rendering the cracks in the set cement carbonized self-healing.CT test results further confirmed the self-healing effect of the calcium-based whisker self-healing agent;after 28 days of self-healing,the volume of the cracks in the set cement incorporated with the calcium-based whisker self-healing agent was reduced by 4,165.95 mm3,a self-healing rate of 72.32%.This indicates that in the CCUS well environment,the incorporation of calcium-based whisker self-healing materials into a cement slurry has a positive impact on the carbonized self-healing process of the cement sheath.