PROCESS PLUGGING CASING STRING IN WELL Russian patent published in 2004 - IPC

FIELD: development of fields of reservoir fluids by wells, construction of wells. SUBSTANCE: casing string carrying shut-off and by-pass devices is sunk into well. First portion of grouting substance is injected and forced through into string clearance through bottom of casing string, next portions of grouting substance are injected and forced through with some time intervals through holes in shut-off and by-pass devices, starting from lowest device. Column clearance is isolated from string clearance in lower part of casing string. Holes in shut-off and by-pass devices are closed after portions of grouting substance are forced through them into string clearance. Mud solution is utilized as grouting substance. Time interval between injections of portions of mud solution is assumed to be equal to time of clay sedimentation from mud solution in string clearance of each preceding portion. Depth of installation of each shut-off and by-pass device is established by upper boundary of clay sedimentation from corresponding portion of mud solution in string clearance. EFFECT: enhanced reliability of plugging of casing string in well. 3 cl, 2 dwg