PROCESS OF BOREHOLE CASING Russian patent published in 1996 - IPC

FIELD: hole drilling. SUBSTANCE: process of borehole casing includes section by section descent of casing string, pressure grouting of casing string, suspension of section of string in anti-ejection equipment mounted on preceding casing string. On termination of borehole casing with lower section anti-ejection equipment is dismounted and string head is installed. This section after descent and joining to lower section is pulled with allowance for temperature conditions of joint of section of casing string. In this case suspension of upper part of upper section of casing string is carried out within period from start of setting of grouting solution but not later than 2/3 of period of its setting. Pulling is performed with effort calculated on basis of temperature conditions in part of bore hole close to head. EFFECT: increased quality of borehole casing.