Guobing Xiong¹, Lu Hong², Zehui Ju³, Xiaoning Lu^3,*, Juwan Jin^3,*

Journal of Renewable Materials, Vol.11, No.9, pp. 3447-3461, 2023, DOI:10.32604/jrm.2023.027430

Abstract The study characterized the curing behaviors of phenol formaldehyde (PF) resin under different vacuum degrees and explored the properties of 9-ply plywood panels hot-pressed under both vacuum and atmospheric conditions. The changes in core temperature and moisture content of the plywood mats during hot pressing were investigated as well. It was found that the gel times and gel temperatures of PF resin decreased with the increase of vacuum degree using a self-made device. FTIR spectra indicated the degree of polycondensation of hydroxymethyl gradually increased with the increase in temperature. It was also observed that a higher degree of vacuum led… More >

Xuesong Xing¹, Renjun Xie¹, Yi Wu¹, Zhiqiang Wu¹, Huanqiang Yang^2,*

FDMP-Fluid Dynamics & Materials Processing, Vol.18, No.6, pp. 1719-1735, 2022, DOI:10.32604/fdmp.2022.019799

Abstract

The bonding quality of the cement sheath interface decreases during well completion because of the change in the casing pressure. To explore the root cause of such phenomena, experiments on the mechanical properties and interface bonding strength of a cement sheath have been carried out taking the LS25-1 high-temperature and high-pressure (HTHP) gas field as an example. Moreover, a constitutive model of the cement sheath has been defined and verified both by means of a full-scale HTHP cement sheath sealing integrity evaluation experiment and three-dimensional finite element simulations. The results show that the low initial cementing surface strength is the… More >