Study on the Performance of Fiber-Latex-Calcium Carbonate Whisker Gas Storage Cement

Abstract

A cement slurry system was designed and optimized in order to meet the strict operation and production requirements of the gas storage well cementing. System formula was G cement +1.5% filtrate reducer +1% dispersant +0.5% defoamer +10% calcium carbonate whisker +8% polychloroprene latex +0.08% polypropylene fiber +0.09%PVA fiber + water. Evaluation experiments showed that the engineering properties of cement slurry system were well, such as good rheology, low water loss, no free liquid, wide adjusted range of thickening time, good anti channeling ability and good suspension stability. The experiment results of cement mechanical strength showed that the 7 days tensile strength of the cement specimen was increased 62.3% higher than that of the neat cement grout, while the 7 days compressive strength was increased 47% and the elastic modulus was reduced 41.7% compared to the standard peak. The micro-structure and morphology of gas storage cement specimens were observed and the mechanism of cement strength enhanced by fiber, latex and calcium carbonate whisker were studied that fiber and calcium carbonate whisker bridged the cracks, reduced cracked tip stress concentration, effectively prevented the development and diffusion of cracks, enhanced cement deformability and reduced the elastic modulus; polychloroprene latex formed latex film on the surface of cement particles and fiber, which improved the cementing strength and the interface micro-structure between fiber and cement, reduced the stress concentration caused by mutant materials, improve the toughness of cement stone greatly.