System and method for multi-zone well treatment

Abstract

A technique is provided for treating a plurality of well zones with a service tool during a single trip downhole. The service tool is run downhole to a selected well zone that is isolated for treatment. Following treatment of the well zone, the service tool is moved to a subsequent well zone isolated for treatment. When the lengths of the well zones to be treated are dissimilar, the active length of the service tool can be adjusted to correspond with the well zone length to optimize the well treatment operation.

1 . A method of treating a well, comprising:
 moving a service tool downhole into a well having a plurality of zones to be treated;   isolating each zone prior to treatment;   circulating a treatment fluid into each isolated zone;   providing an entry port into the service tool to accommodate any returning treatment fluid; and   changing the position of the entry port relative to the service tool to maintain the entry port proximate a bottom of each isolated zone when treating subsequent zones having differing lengths.   
   
   
       2 . The method as recited in  claim 1 , wherein moving comprises running the service tool in-hole with a completion assembly. 
   
   
       3 . The method as recited in  claim 1 , wherein moving comprises moving the service tool downhole in the form of a washpipe. 
   
   
       4 . The method as recited in  claim 1 , wherein isolating comprises setting a plurality of isolation packers. 
   
   
       5 . The method as recited in  claim 1 , wherein changing comprises selectively opening a valve of a plurality of valves positioned along the service tool. 
   
   
       6 . The method as recited in  claim 5 , wherein selectively opening comprises sealing the valve in a seal bore positioned proximate an isolation packer at a downhole end of the zone subject to treatment; and subsequently opening the valve. 
   
   
       7 . The method as recited in  claim 5 , wherein selectively opening comprises creating a pressure differential between the treatment fluid and the next sequential zone downhole of the valve. 
   
   
       8 . The method as recited in  claim 5 , wherein selectively opening comprises using an internal pressure within the service tool to open the valve. 
   
   
       9 . The method as recited in  claim 5 , wherein selectively opening comprises opening the valve with a magnetic force. 
   
   
       10 . The method as recited in  claim 5 , further comprising locking the valve in an open position. 
   
   
       11 . The method as recited in  claim 1 , further comprising selectively isolating a bottom of the service tool with the valve 
   
   
       12 . A system for treating a multi-zone well, comprising:
 a service tool having a plurality of valves arranged along the service tool, each valve cooperating with a sealing member;   a tubular member disposed around the service tool, the tubular member having a bore region sized to form a seal with each valve via the sealing member as each valve is moved into the bore region; and   an isolation packer disposed externally of the tubular member proximate an exterior of the bore region, wherein any valve of the plurality of valves can be moved into sealing engagement with the bore region to ensure the effective length of the service tool corresponds with the length of a well zone to be treated.   
   
   
       13 . The system as recited in  claim 12 , wherein each valve is actuated by one of a group consisting of: (i) pressure actuation, the pressure actuation requiring formation of a seal via the sealing member positioned between the valve and the bore region; (ii) magnetic actuation: and (iii) internal pressure actuation within the service tool. 
   
   
       14 . (canceled) 
   
   
       15 . (canceled) 
   
   
       16 . The system as recited in  claim 12 , wherein the service tool has a bottom opening; and wherein at least one of the valves comprises an in-line valve that can selectively open and close the bottom opening. 
   
   
       17 . The system as recited in  claim 16 , wherein the in-line valve is a one-way valve. 
   
   
       18 . The system as recited in  claim 16 , wherein the in-line valve is a two-way valve. 
   
   
       19 . The system as recited in  claim 12 , wherein each valve comprises a lock to lock the valve in an open position. 
   
   
       20 . The system as recited in  claim 19 , wherein the lock is a hydraulic lock. 
   
   
       21 . The system as recited in  claim 12 , wherein each valve is biased toward a closed position. 
   
   
       22 . A system, comprising:
 a well treatment system having:
 a bore region; 
 an isolation packer disposed proximate an exterior of the bore region; and 
 a valve selectively movable to a position inside the bore region for sealing engagement with the bore region, wherein the valve may be selectively actuated to open an entry port for admitting fluid into the valve once sealed with the bore region. 
   
   
   
       23 . The system as recited in  claim 22 , wherein the valve comprises a plurality of valves that may be selectively opened when sealed with the bore region to accommodate treatment of well zones with differing lengths, and
 wherein the isolation packer comprises a plurality of isolation packers located to isolate a plurality of well zones having differing lengths.   
   
   
       24 . (canceled) 
   
   
       25 . A method, comprising:
 sequentially treating a plurality of well zones with a single trip downhole; and:   adjusting the active length of a service tool according to the length of each well zone treated while maintaining a fluid return path port proximate a lower region of the well zone treated.   
   
   
       26 . The method as recited in  claim 25 , wherein sequentially treating comprises running the service tool in-hole with a completion assembly. 
   
   
       27 . The method as recited in  claim 25 , wherein adjusting comprises positioning a plurality of valves along the service tool such that a valve located at the lower end of an isolated well zone can selectively be opened. 
   
   
       28 . The method as recited in  claim 27 , wherein the valve located at the lower end of the well zone is selectively opened by creating a pressure differential between the pressure of treatment fluid in a treatment zone and the pressure in an adjacent well zone, and
 wherein each valve comprises a seal member positioned to seal with a seal bore located proximate a tower end of the treatment zone.   
   
   
       29 . (canceled)