Isolation plug

Claim 1

An apparatus for isolating an upper portion of a well bore from a lower portion of said well bore, comprising: an annular packer means including a packer body having a longitudinal passageway disposed therethrough, and including an expandable packing element for sealing an annulus between said packer body and said well bore between said upper and lower portions of said well bore; isolation means, connected to said packer body, for blocking said longitudinal passageway and thereby isolating said upper portion of said well bore from said lower portion of said well bore, said isolation means including: a housing having a central bore communicated with said longitudinal passageway; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to communicate said upper portion of said well bore with said lower portion of said well bore, said releasable retaining means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal passageway of said packer body; and an isolation casing connected to said packer body, said isolation casing including a central cavity for receiving said housing of said isolation means therein; an operating tool string initially disposed through said longitudinal passageway of said packer body; and wherein said housing of said isolation means is initially attached to said operating tool string so that said housing is moved longitudinally with said operating tool string relative to said packer body and said isolation casing.

Claim 2

An apparatus for isolating an upper portion of a well bore from a lower portion of said well bore, comprising: an annular packer means including a packer body having a longitudinal passageway disposed therethrough, and including an expandable packing element for sealing an annulus between said packer body and said well bore between said upper and lower portions of said well bore; isolation means, connected to said packer body, for blocking said longitudinal passageway and thereby isolating said upper portion of said well bore from said lower portion of said well bore, said isolation means including: a housing having a central bore communicated with said longitudinal passageway; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to communicate said upper portion of said well bore with said lower portion of said well bore, said releasable retaining means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal passageway of said packer body; and an isolation casing connected to said packer body, said isolation casing including a central cavity for receiving said housing of said isolation means therein; an operating tool string initially disposed through said longitudinal passageway of said packer body; and wherein said housing of said isolation means is initially attached to said operating tool string so that said housing is moved longitudinally with said operating tool string relative to said packer body and said isolation casing.

Claim 13

An apparatus for packing a zone of a well bore with a particulate material, comprising: an upper packer means including a packer body having a longitudinal body passageway disposed therethrough and including an expandable packing element for sealing against said well bore at an upper end of said zone, said packer body including a lower body extension having port means associated therewith for communicating said zone with an interior of a supply tubing string means for supplying said particulate material to said zone; intermediate tubing connected to a lower end of said packer body, said intermediate tubing having a longitudinal tubing passageway disposed therethrough, said tubing passageway being communicated with said longitudinal body passageway of said upper packer means; production screen means, connected to a lower end of said intermediate tubing, for communicating said zone of said well bore with a lower end of said longitudinal tubing passageway of said intermediate tubing; isolation means, disposed in said intermediate tubing, for blocking said longitudinal tubing passageway and thereby isolating said zone of said well bore from said well bore above said upper packer means after said zone is packed with said particulate material and said port means is closed, said isolation means being releasable for unblocking said longitudinal tubing passageway and thereby communicating said zone with a production tubing connected to said packer body for producing fluid from said zone, said isolation means including: a housing having a central bore communicated with said longitudinal tubing passageway; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; and releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to unblock said central bore and said longitudinal tubing passageway, said releasable retaining means of said isolation means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal tubing passageway; a seal bore nipple connected to a lower end of said production screen means; a tell tail screen means connected to a lower end of said seal bore nipple; and a wash pipe, attached to a lower end of said supply tubing means; wherein, said intermediate tubing includes an isolation casing having a central cavity for receiving said housing of said isolation means therein; said packer body of said upper packer means further includes a second port means associated therewith for communicating an interior of said wash pipe with said well bore above said upper packer means; and said housing of said isolation means is initially attached to a lower end of said wash pipe and said housing further includes a cylindrical outer surface sealingly received in said seal bore nipple and includes a circulating port associated therewith for communicating said interior of said wash pipe with said zone of said well bore through said tell tail screen means.

Claim 14

An apparatus for packing a zone of a well bore with a particulate material, comprising: an upper packer means including a packer body having a longitudinal body passageway disposed therethrough and including an expandable packing element for sealing against said well bore at an upper end of said zone, said packer body including a lower body extension having port means associated therewith for communicating said zone with an interior of a supply tubing string means for supplying said particulate material to said zone; intermediate tubing connected to a lower end of said packer body, said intermediate tubing having a longitudinal tubing passageway disposed therethrough, said tubing passageway being communicated with said longitudinal body passageway of said upper packer means; production screen means, connected to a lower end of said intermediate tubing, for communicating said zone of said well bore with a lower end of said longitudinal tubing passageway of said intermediate tubing; isolation means, disposed in said intermediate tubing, for blocking said longitudinal tubing passageway and thereby isolating said zone of said well bore from said well bore above said upper packer means after said zone is packed with said particulate material and said port means is closed, said isolation means being releasable for unblocking said longitudinal tubing passageway and thereby communicating said zone with a production tubing connected to said packer body for producing fluid from said zone, said isolation means including: a housing having a central bore communicated with said longitudinal tubing passageway; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; and releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to unblock said central bore and said longitudinal tubing passageway, said releasable retaining means of said isolation means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal tubing passageway; a seal bore nipple connected to a lower end of said production screen means; a tell tail screen means connected to a lower end of said seal bore nipple; and a wash pipe, attached to a lower end of said supply tubing means; wherein, said intermediate tubing includes an isolation casing having a central cavity for receiving said housing of said isolation means therein; said packer body of said upper packer means further includes a second port means associated therewith for communicating an interior of said wash pipe with said well bore above said upper packer means; and said housing of said isolation means is initially attached to a lower end of said wash pipe and said housing further includes a cylindrical outer surface sealingly received in said seal bore nipple and includes a circulating port associated therewith for communicating said interior of said wash pipe with said zone of said well bore through said tell tail screen means.

Claim 17

An apparatus for isolating an upper portion of a well bore from a lower portion of said well bore, comprising: an annular packer means including a packer body having a longitudinal passageway disposed therethrough, and including an expandable packing element for sealing an annulus between said packer body and said well bore between said upper and lower portions of said well bore; isolation means, connected to said packer body, for blocking said longitudinal passageway and thereby isolating said upper portion of said well bore from said lower portion of said well bore, said isolation means including: a housing having a central bore communicated with said longitudinal passageway and including an upward facing support surface disposed in said central bore; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; and releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to communicate said upper portion of said well bore with said lower portion of said well bore, said releasable retaining means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal passageway of said packer body, a downward facing surface located above said support surface of said housing and engaged with said support surface to retain said plug means in said central bore of said housing, and resilient spring means including a plurality of spring collet fingers extending upwardly from said plug means for resiliently urging said downward facing surface and said support surface into engagement, said spring means being displaceable to disengage said downward facing surface and said support surface; wherein said downward facing surface of said releasable retaining means is defined on a plurality of shoulders, one of which shoulders extends radially outward from each of said spring collet fingers; and wherein said means for preventing release of said plug means includes a back-up means for preventing said resilient spring means from being displaced due to fluid pressure variations within said longitudinal passageway of said packer body, said back-up means including pressure balanced piston means initially located between and engaging radially inner surfaces of at least two of said spring collet fingers to hold said shoulders of said at least two spring collet fingers within said annular recess of said central bore of said housing, said piston means being movable from said initial location downward relative to said spring collet fingers to a second position for allowing said spring collet fingers to be displaced radially inward due to a downward force exerted on said plug means thereby releasing said plug means from said housing; and wherein said piston means is an annular piston means having a central opening disposed longitudinally therethrough, and said piston means includes a filter means, covering said central opening, for preventing particulate material from passing through said opening and collecting on top of the plug means.

Claim 18

An apparatus for isolating an upper portion of a well bore from a lower portion of said well bore, comprising: an annular packer means including a packer body having a longitudinal passageway disposed therethrough, and including an expandable packing element for sealing an annulus between said packer body and said well bore between said upper and lower portions of said well bore; isolation means, connected to said packer body, for blocking said longitudinal passageway and thereby isolating said upper portion of said well bore from said lower portion of said well bore, said isolation means including: a housing having a central bore communicated with said longitudinal passageway and including an upward facing support surface disposed in said central bore; plug means disposed in said central bore for blocking said central bore and said longitudinal passageway; and releasable retaining means for retaining said plug means in said central bore and for subsequently releasing said plug means so that it may be displaced from said central bore to communicate said upper portion of said well bore with said lower portion of said well bore, said releasable retaining means including means for preventing release of said plug means due to fluid pressure variations within said longitudinal passageway of said packer body, a downward facing surface located above said support surface of said housing and engaged with said support surface to retain said plug means in said central bore of said housing, and resilient spring means including a plurality of spring collet fingers extending upwardly from said plug means for resiliently urging said downward facing surface and said support surface into engagement, said spring means being displaceable to disengage said downward facing surface and said support surface; wherein said downward facing surface of said releasable retaining means is defined on a plurality of shoulders, one of which shoulders extends radially outward from each of said spring collet fingers; and wherein said means for preventing release of said plug means includes a back-up means for preventing said resilient spring means from being displaced due to fluid pressure variations within said longitudinal passageway of said packer body, said back-up means including pressure balanced piston means initially located between and engaging radially inner surfaces of at least two of said spring collet fingers to hold said shoulders of said at least two spring collet fingers within said annular recess of said central bore of said housing, said piston means being movable from said initial location downward relative to said spring collet fingers to a second position for allowing said spring collet fingers to be displaced radially inward due to a downward force exerted on said plug means thereby releasing said plug means from said housing; and wherein said piston means is an annular piston means having a central opening disposed longitudinally therethrough, and said piston means includes a filter means, covering said central opening, for preventing particulate material from passing through said opening and collecting on top of the plug means.

Claim 19

A method of gravel packing a zone of a well bore and of isolating an upper portion of said well bore from said zone located therebelow upon completion of said gravel packing operation on said zone, said method comprising the steps of: setting an upper packer means in said well bore at an upper end of said zone; gravel packing said zone by flowing a gravel slurry down a tubing string connected to a packer body of said upper packer means and through port means associated with said packer body into said zone; blocking a longitudinal passageway of said packer body with a releasable isolation means prior to completely withdrawing said tubing string from said packer body; closing said port means prior to completely withdrawing said tubing string from said packer body; completely withdrawing said tubing string from said packer body, thereby communicating said longitudinal passageway of said packer body with said upper portion of said well bore; and thereby isolating said upper portion of said well bore from said gravel packed zone so long as said longitudinal passageway remains blocked by said releasable isolation means.

Claim 20

A method of gravel packing a zone of a well bore and of isolating an upper portion of said well bore from said zone located therebelow upon completion of said gravel packing operation on said zone, said method comprising the steps of: setting an upper packer means in said well bore at an upper end of said zone; gravel packing said zone by flowing a gravel slurry down a tubing string connected to a packer body of said upper packer means and through port means associated with said packer body into said zone; blocking a longitudinal passageway of said packer body with a releasable isolation means prior to completely withdrawing said tubing string from said packer body; closing said port means prior to completely withdrawing said tubing string from said packer body; completely withdrawing said tubing string from said packer body, thereby communicating said longitudinal passageway of said packer body with said upper portion of said well bore; and thereby isolating said upper portion of said well bore from said gravel packed zone so long as said longitudinal passageway remains blocked by said releasable isolation means.