METHOD OF INSULATING FORMATION WATER INFLOW Russian patent published in 2005 - IPC

FIELD: oil and gas production.

SUBSTANCE: invention relates to insulating formation water inflow in gas and gas condensate wells with the aid of coltubing techniques. In particular, flexible conduit is descended through the tube space of well operated under pressure to the bottom with the aid of coltubing installation. Latches on tube and annulus spaces are opened. Well hole is filled through flexible conduit with gas condensate. Grouting mortar is prepared in preparation block by mixing cement mortar with setting retardant and mortar flowability enhancer in a calculated amount needed to prevent formation water inflow. Further, flushing fluid, e.g. methanol, is pumped through flexible conduit in amount constituting 0.3-0.6 volume of flexible conduit. Annulus space is closed and grouting mortar is pumped through flexible conduit in amount required to fill well hole in interval of water-inflow part of formation. When grouting mortar in hole rises to specified height, tube space is closed and grouting mortar contained in flexible conduit is forced into water-inflow part of formation by in series pumped flushing fluid and displacing solution: for example first methanol in amount 1.0-1.3 volumes of flexible conduit and then gas condensate in required amount, which however does not exceed internal volume of flexible conduit, until grouting mortar begins being pumped in amount of 0.3-0.5 volumes of flexible conduit. Then tube and annulus spaces of well are opened and gas condensate begins being simultaneously pumped into tube and annulus spaces in order to prevent rise of grouting mortar therein above interval of the water-inflow part of formation. Thereafter, bottom of flexible conduit is raised by 1 m above indicated interval and excess of grouting mortar is cut and washed away with gas condensate passed through flexible conduit into tube space, where excess grouting mortar remains in fluid state. After cement setting expectation time, flexible conduit is descended to the top of cement column and tests the latter for strength applying 4.0-5.0 kN loading by means of injector of coltubing installation through flexible conduit. Finally, cement bridging is subjected to hydraulic pressurization and flexible conduit is removed from well.

EFFECT: enabled formation water inflow insulation without killing of well and restricted pollution of water-inflow part of formation.

3 cl, 1 dwg