US 8,783,351 B2 · Method and apparatus for cementing a wellbore

Abstract

A cementing tool (20) capable of being installed in a casing string (10) and configured to selectively permit the flow of cement through one or more ports (34) in the tool is provided. The ports (34) are normally sealed by rupture disc assemblies (36) comprising a rupture disc (62) that can be opened to permit flow of cement through the casing string central bore (32) and into the annulus (14) defined by the casing string (10) and the downhole formation (16). The cementing tool (20) is particularly useful during cementing operations in which the annulus (14) has become blocked by a collapsed portion of the formation by allowing the obstruction (104) to be bypassed and the flow of cement (100) into the annulus to be continued without substantial interruption. Tool (20) may also be used in multistage cementing operations.

Claims32

Dependent claims

A cementing tool configured for attachment to a casing string and operable to direct a fluid flowing within said casing string into an annulus defined between said casing string and a downhole formation, said tool comprising:

a tubular body comprising a cylindrical sidewall having an interior surface and an exterior surface, said sidewall interior surface defining a central passage;
at least one channel-forming member defining a channel that is located outboard from said central passage and has a longitudinal central axis different from that of said central passage, said channel having at least one open end comprising an opening that is longitudinal central axis transverse to said channel permitting communication between said channel and annulus when said tool is interposed between adjacent sections of casing string;
at least one port formed in said sidewall that defines a path for fluid flow between said central passage and said channel;
and
at least one rupture disc assembly comprising a rupture disc, said rupture disc when in an unruptured state being disposed in fluid blocking relationship between said central passage and said at least one open end.

2 more elements

A method of cementing a casing string comprising:

positioning a casing string comprising at least two adjacent casing sections and at least one cementing tool interposed between said at least two adjacent casing sections in a downhole formation, said casing string also comprising a central bore, said casing string and said formation defining an annulus located therebetween, said cementing tool including:
a tubular body comprising a cylindrical sidewall having an interior surface and an exterior surface, said sidewall interior surface defining a central passage;
at least one channel-forming member defining a channel that is located outboard from said central passage and has a longitudinal central axis different from that of said central passage, said channel having at least one open end comprising an opening that is in a plane transverse to said channel longitudinal central axis permitting communication between said channel and annulus;
at least one port formed in said sidewall that defines, at least in part, a path for fluid flow between said central passage and said annulus;
and
at least one rupture disc assembly comprising a rupture disc, said rupture disc when in an unruptured state being disposed in fluid blocking relationship between said central passage and said annulus;
and
injecting cement downhole through said casing string central bore and causing said cement to flow into said annulus.

5 more elements

Dependencies are inferred from the claim text.

Method and apparatus for cementing a wellbore

Life of this patent

Method and apparatus for cementing a wellbore

Life of this patent

Abstract

Claims32