METHOD FOR SEALING OFF A WATER ZONE IN A PRODUCTION WELL DOWNHOLE AND A SEALING ARRANGEMENT
The invention relates to a sealing method for sealing off a leak in a casing ( 2 ) or for sealing of a production zone ( 1 ) where the casing ( 2 ) having a circumference and perforations ( 3 ) is situated in a borehole downhole, but with a distance to the inner wall of the borehole, creating an intervening space ( 4 ) there between. The sealing method comprises the steps of injecting a composition ( 5 ) for making a first circumferential seal ( 6 ) in the intervening space ( 4 ) at a first position ( 7 ) of the casing in one end of the production zone through holes situated along a first intersecting line ( 8 ) where a first plane intersects the circumference of the casing; filling the intervening space at a first position in a radial direction of the casing; injecting a composition ( 5 ) for making a second circumferential seal ( 9 ) in the intervening space ( 4 ) at a second position ( 10 ) of the casing in another end of the production zone through holes situated along a second intersecting line ( 11 ) where a second plane intersects the circumference of the casing; filling the intervening space at a second position in a radial direction of the casing; inserting a liner ( 12 ) into the casing ( 2 ) opposite the perforations ( 3 ) and extending between and at least partly covering both the first and the second circumferential seal; and expanding the liner until the liner is pressing against the casing whereby the liner together with the first and the second circumferential seal isolate the production zone. The composition is able to harden once injected into the intervening space.
1 . Sealing method for sealing off a leak in a casing ( 2 ) or for sealing off a production zone ( 1 ) where the casing ( 2 ) having a circumference and perforations ( 3 ) is situated in a borehole downhole, but with a distance to an inner wall of the borehole, creating an intervening space ( 4 ) there between, comprising the steps of:
injecting a composition ( 5 ) for making a first circumferential seal ( 6 ) in the intervening space ( 4 ) at a first position ( 7 ) of the casing in one end of the production zone through holes situated along a first intersecting line ( 8 ) where a first plane intersects the circumference of the casing,
filling the intervening space at a first position in a radial direction of the casing,
injecting a composition ( 5 ) for making a second circumferential seal ( 9 ) in the intervening space ( 4 ) at a second position ( 10 ) of the casing in another end of the production zone through holes situated along a second intersecting line ( 11 ) where a second plane intersects the circumference of the casing,
filling the intervening space at a second position in a radial direction of the casing,
inserting a liner ( 12 ) into the casing ( 2 ) covering the holes ( 3 ) and extending between and at least partly covering both the first and the second circumferential seal, and
expanding the liner until the liner is pressing against the casing whereby the liner together with the first and the second circumferential seal isolate the production zone.
2 . Sealing method according to claim 1 , wherein the composition comprises a compound which is able to harden, expand, swell or paste once injected into the intervening space.
3 . Sealing method according to claim 1 , wherein the holes through which the composition is injected are positioned directly opposite each other in the casing.
4 . Sealing method according to claim 1 , wherein the holes are some of the perforations.
5 . Sealing method according to claim 1 , further comprising the step of making the holes prior to at least one of the injection steps.
6 . Sealing method according to claim 5 , comprising a third injection step where composition is injected for making a third circumferential seal ( 15 ) in the intervening space ( 4 ) through holes made at a distance from the perforations.
7 . Sealing method according to claim 1 , further comprising the step of making new perforations in the casing for letting oil fluid flow into the casing from a new and second production zone ( 14 ).
8 . Sealing method according to claim 1 , wherein the composition is expanded for making the circumferential seals.
9 . Sealing method according to claim 1 , comprising a further step of injecting an intermediate circumferential seal between the first and the second circumferential seal.
10 . Sealing arrangement for sealing off a leak in a casing or for sealing off a production zone where the casing having a circumference and perforations is situated in a borehole downhole, but with a distance to an inner wall of borehole, creating an intervening space between casing and the borehole, comprising:
a first circumferential seal of composition in the intervening space at a first position of the casing in a first end of the production zone,
a second circumferential seal of composition in the intervening space at a second position of the casing in a second end of the production zone, and
an expanded liner in between the first and the second circumferential seal, for isolation of the production zone.