Abstract: The burial depth the reservoir of Changshen 5 well is 5,200m and the temperature reaches as high as 183℃. In view of the characteristics of the reservoir, lab test is launched on the formulations of ultra-high temperature and low-damage fracturing fluid, high-temperature crosslinker and synergist are synthesized.Meanwhile, performance evaluation is conducted on the new carboxy methyl-guanidine (CMG) ultra-high temperature fracturing fluid system. Lab test results show that the CMG fracturing fluid features in high temperature (180℃), low concentration, low residue, low damage, and low friction. The fracturing fluid system has been applied to Changshen 5 well successfully, and the production was enhanced a lot.

Key words: ultra-high temperature, CMG fracturing fluid, deep well, volcanic gas well, fracture, southern Songliao Basin