Baker Hughes Corporation

Leo E Hill, Jr

Christian F Bayne

The apparatus includes a gravel pack assembly comprising a gravel pack body and a crossover tool. The gravel pack body comprises a pressure set packer, one or more production screens and a plurality of axial position indexing lugs. The crossover tool comprises auxiliary flow chambers, packer by-pass channels, a crossover tool check valve and an axial position indexing collet. The gravel pack body and crossover tool are assembled coaxially as a cooperative unit by a threaded joint and the unit is threadably attached to the bottom end of a tool string for selective placement within the wellbore. Set of the packer secures the gravel pack body to the well casing and seals the casing annulus around the gravel pack assembly. A positive fluid pressure is maintained on the wellbore wall in the production zone throughout the gravel packing procedure and in particular, during the packer seal test interval when fluid pressure that is egual to or greater than the normal hydrostatic pressure is maintained on the production zone wall under the gravel pack body packer while greater test pressure above the hydrostatic is imposed in the wellbore annulus above the packer.

Method and apparatus for open hole gravel packing

The apparatus includes a gravel pack assembly comprising a gravel pack body and a crossover tool. The crossover tool comprises auxiliary flow chambers and channels around a casing packer and a crossover tool check valve. The gravel pack body and crossover tool are assembled coaxially as a cooperative unit by a threaded joint. The assembly is threadably attached to the bottom end of a tool string for selective placement within the wellbore. Set of the packer secures the gravel pack body to the well casing and seals the casing annulus around the gravel pack assembly. After setting the packer, the tool string is rotated to release the threaded assembly joint between the crossover tool and the gravel pack extension. The desired flow function is determined by selective axial positionment of the crossover tool within the gravel pack body. When the gravel pack is in place, the crossover tool is axially positioned to flush residual aggregate from the tool string bore. The gravel pack body is dedicated to the wellbore and the crossover tool withdrawn and replaced by a production tube.

The present invention provides apparatus and method for gravel packing open holes wherein hydrostatic pressure is maintained above the formation pressure (&ldquo;overburdened condition&rdquo;) throughout the gravel pack process. The apparatus includes a completion string which contains a flow restriction device, a crossover device and a packer each above and below the crossover device. The string is set in the wellbore with the flow restriction device adjacent the producing formation. The upper packer and the crossover device are set, which allows the gravel fluid to pass to the annulus, and return through the string. After gravel packing, the lower packer is set. The crossover device and the upper packer are retrieved from the wellbore leaving the flow restriction device and the lower packer in the wellbore. The system maintains the wellbore under overburdened condition throughout the gravel packing process.

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Huffman, TX, United States of America

Leo E Hill, Jr