Downhole packer apparatus promoting radial flow

Abstract

A downhole packer apparatus including a packer disposed along a downhole sampling tool, wherein an outer surface of the packer includes an uneven surface portion with one or more flow channels locatable between the outer surface of the one packer and a facing wellbore wall, the flow channels promoting radial flow of formation fluids to one or more surface conduits leading to flow lines located inside the one packer. A method of obtaining a formation sample using the downhole packer apparatus is also described.

What is claimed is: 
     
         1 . A downhole packer apparatus, comprising:
 a packer disposed along a downhole sampling tool, wherein an outer surface of the packer includes an uneven surface portion with one or more flow channels locatable between the outer surface of the one packer and a facing wellbore wall, the flow channels promoting radial flow of formation fluids to one or more surface conduits leading to flow lines located inside the one packer.   
     
     
         2 . The apparatus of  claim 1 , wherein the uneven surface portion includes grooves in the outer surface to thereby define the flow channel. 
     
     
         3 . The apparatus of  claim 1 , wherein the uneven surface portion includes raised ridges on the outer surface to thereby define the flow channel. 
     
     
         4 . The apparatus of  claim 1 , wherein the one or more flow channel defines a spirally-shaped channel pattern along the uneven surface portion. 
     
     
         5 . The apparatus of  claim 1 , wherein the one or more flow channels are non-intersecting and separated from each other along the uneven surface portion. 
     
     
         6 . The apparatus of  claim 1 , wherein the one or more flow channel are first channels and the uneven surface portion further includes second flow channels that promote substantially longitudinal flow of the formation fluids between the first channels. 
     
     
         7 . The apparatus of  claim 1 , wherein the packer is a first packer and the apparatus further includes a second packer disposed along the downhole sampling tool and the first and second packers are longitudinally spaced apart, and wherein:
 the uneven surface portion of the first packer is located proximate to the second packer,   the first packer surface further includes an even surface portion located distal to the second packer, and   the even surface portion deters passage of the formation fluids between the even surface portion and the facing wellbore wall.   
     
     
         8 . The apparatus of  claim 7 , wherein an outer surface of the second packer further includes a uneven surface portion with one or more second channels locatable between the outer surface of the second packer and the facing wellbore wall, the second flow channels promoting the radial flow of the formation fluids to one or more second surface conduits leading to second flow lines located inside the second packer. 
     
     
         9 . The apparatus of  claim 8 , wherein:
 the uneven surface portion of the second packer is located proximate to the first packer,   the second packer further includes an second even surface portion distal to the first packer, and   the second even surface portion deters passage of the formation fluids between the second even surface portion and the facing wellbore wall.   
     
     
         10 . The apparatus of  claim 1 , wherein the first and second packers each have a first interior chamber underlying the even surface portions and a second interior chamber underlying the uneven surface portion wherein the first and second interior chambers are connected by a pressure offset valve, the pressure offset valve set to prevent the second interior chambers to expand until the first interior chambers have expanded to contact the facing wellbore wall. 
     
     
         11 . The apparatus of  claim 1 , wherein the packer is a central packer and the apparatus further includes second and third packers disposed along the downhole sampling tool, the second and third packers longitudinally spaced apart with the central packer located there-between. 
     
     
         12 . The apparatus of  claim 11 , wherein the uneven surface of the central packer extends over an entire longitudinal length of the central packer. 
     
     
         13 . The apparatus of  claim 11 , wherein the second and third packers have even surface portions that extend over entire longitudinal lengths of the second and third packers. 
     
     
         14 . The apparatus of  claim 11 , wherein one or both of the second and third packers, include uneven surface portions having flow channels locatable between the outer surface of the one packer and a facing wellbore wall, the flow channels promoting radial flow of formation fluids to surface conduits leading to flow lines located inside the first and second packers. 
     
     
         15 . The apparatus of  claim 1 , wherein the downhole packer apparatus is included in a system for drilling operations of a subterranean formation. 
     
     
         16 . A method, comprising:
 obtaining a formation sample using a downhole packer apparatus deployed within a borehole of a system for drilling operations of a subterranean formation, including:
 disposing the downhole packer apparatus along a downhole sampling tool, wherein the downhole packer apparatus includes a packer, an outer surface of the packer includes an uneven surface portion with one or more flow channels locatable between the outer surface of the one packer and a facing wellbore wall, the flow channels promoting radial flow of formation fluids to one or more surface conduits leading to sample flow lines located inside the one packer; 
 isolating a sampling zone of the subterranean formation adjacent to the borehole to create a fluid seal between the downhole packer apparatus and a wall of the borehole; and 
 collecting the formation fluids into the one or more surface conduits to provide the formation sample. 
   
     
     
         17 . The method of  claim 16 , further including removing a mudcake lining the wall of the sampling zone including flowing drilling fluids through the sampling zone and then inflating a chamber of the packer underlying the uneven surface portion, wherein the removing is before collecting the formation fluids and after the isolating of the sampling zone. 
     
     
         18 . The method of  claim 16 , wherein isolating the sampling zone includes expanding upper and lower packers of the downhole packer apparatus and disposed along the downhole sampling tool, wherein the packer is a central packer located between the upper and lower packers. 
     
     
         19 . The method of  claim 16 , wherein isolating the sampling zone includes expanding a chamber underlying an even surface portion of the packer, wherein the packer is one of an upper or lower packer of the downhole packer apparatus. 
     
     
         20 . The method of  claim 16 , wherein isolating the sampling zone includes expanding a chamber underlying an even surface portion a second packer, wherein the second packer is the other of a lower or upper packer of the downhole packer apparatus.