METHOD OF CEMENT BRIDGE FORMING IN WELL Russian patent published in 2004 - IPC

FIELD: oil industry, particularly forming cement bridges in gas and gas-condensate wells during repairing, conservation or abandonment thereof with the use of coiled tubing equipment.

SUBSTANCE: method involves lowering flexible tube into high-pressure well with the use of coiled tube plant up to reaching well bottom; filling well bore with gas condensate through flexible tube with opening well and annuity spaces; lifting flexible tube shoe up to level of cement bridge creation; preparing plugging mix in preparation station by mixing cement mortar with cement setting retarder and reagent increasing mix fluidity; pumping displacement liquid, particularly methanol, into well through flexible pipe in amount of 0.3 - 0.6 of flexible tube volume; feeding plugging mix in amount sufficient for cement bridge forming; forcing plugging mix through well by alternate injection of displacement liquid and plugging-back solution, for instance by initial pumping methanol in amount of 1.0 - 1.3 of flexible tube volume and then feeding gas-condensate in required amount not exceeding total flexible tube volume up to cleaning flexible tube from plugging mix; rising flexible tube shoe to level located 1 m above designed top of cement bridge; performing cutting cement bridge top by gas condensate injected through flexible tube; moving excess plugging mix into well space and leaving excess plugging mix into well space in liquid state; lowering flexible tube into well up to reaching cement bridge top after cement bridge hardening; performing strength test of cement bridge by applying load through coiled tube plant injector and flexible tube with force not exceeding 4.0 - 5.0 kN; carrying out hydraulic pressure test of cement bridge; removing flexible tube out of well.

EFFECT: possibility of cement bridge arrangement without killing of well.

1 dwg