Method and apparatus for open hole gravel packing

摘要

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.