Method and apparatus for single-trip wellbore treatment

Abstract

The apparatus consists of a tubular housing carried into the well on a workstring. A series of spaced isolation modules is provided for each zone and carried into the well on a tubular conduit. The first, or most downstream module includes first and second sealing mechanisms to isolate the first zone to be treated. A full bore valve is provided that is activated to closed position by an activating component in response to a source of a first level of pressure to isolate the first zone from other parts of the well bore. A port within the housing is initially blocked but selectively opened concurrently with the activation of the first sealing means to manipulate the second sealing mechanism to fully isolate the selected zone and the module. As the module is activated, a second full bore valve is activated to seal the interior of the housing upstream of the first module by manipulation of the tubular string.

1 ) A full bore single trip multizone subterranean well treating apparatus, carriable into the well on a tubular workstring, said apparatus comprising:
 (a) a tubular housing carried on said workstring and including a first fluid passageway therethrough;   (b) a plurality of treatment modules in securing relationship with said workstring, each said module being pre-determinedly spaced on said housing for operable alignment with a zone in said well to be selectively treated, each said module including:
 (1) a tubular housing member including a treatment fluid port therein and including a selectively communicable control chamber; 
 (2) first and second sealing mechanisms on said tubular housing for isolating a selected first zone to be treated from another portion of said well; 
 (3) a first full bore valving mechanism initially positioned within said housing in a full bore open position and selectively activatable to a closed position blocking fluid under pressure from being transmitted within said tubular housing and across said valving member; 
 (4) first activation means for said first full bore valving means initially responsive to a first level of fluid pressure applied through said workstring and into said housing member and shiftable from a first inactive position to a second activated position, whereby said port is opened to place said chamber in fluid communication with said first fluid passageway of said tubular housing, and further whereby fluid pressure within said housing member above the said first level of fluid pressure activates said first sealing mechanism to set said first sealing mechanism in said well; 
 (5) a second fluid flow passageway within said housing and including an initially blocked fluid port opening to the interior of said tubular housing, said blocked fluid port being opened to said tubular housing interior during activation of said first sealing means; and 
 (6) second activation means responsive to fluid pressure in excess of the pressure required to activate the second sealing mechanism to isolate the said selected first zone from the well bore upstream of said selected first zone and thereafter, upon application of additional pressure within the tubular housing, to fully open said treatment port for transmission of a treating fluid within said tubular housing and into said selected first zone. 
   
     
     
         2 ) The apparatus of  claim 1 , further comprising in each of said modules positioned in said well upstream of the module for isolating the selected first zone to be treated from a second zone to be treated, full bore valving means initially positioned on said housing in an open position allowing fluid flow thereacross, and shiftable to a closed position in response to mechanical manipulation of said tubular workstring, whereby fluid flow across said valving means in said housing is sealingly blocked. 
     
     
         3 ) A single trip, full bore method for treating a plurality of zones within a subterranean well, comprising the steps of:
 (a) introducing into the well a tubular workstring comprising:
 (1) a tubular housing carried on said workstring and including a first fluid passageway therethrough; 
 (2) a plurality of zone isolation modules in securing relationship with said workstring, each said module being pre-determinedly spaced on said housing for operable alignment with a zone in said well to be selectively treated, each said module including:
 (i) a tubular housing member including a treatment fluid port therein and including a selectively communicable control chamber; 
 (ii) first and second sealing mechanisms on said tubular housing for isolating a selected first zone to be treated from another portion of said well; 
 (iii) a first full bore valving mechanism initially positioned within said housing in a full bore open position and selectively activatable to a closed position blocking fluid under pressure from being transmitted within said tubular housing and across said valving member; 
 (iv) first activation means for said first full bore valving means initially responsive to a first level of fluid pressure applied through said workstring and into said housing member and shiftable from a first inactive position to a second activated position, whereby said port is opened to place said chamber in fluid communication with said first fluid passageway of said tubular housing, and further whereby fluid pressure within said housing member above the said first level of fluid pressure activates said first sealing mechanism to set said first sealing mechanism in said well; 
 (v) a second fluid flow passageway within said housing and including an initially blocked fluid port opening to the interior of said tubular housing, said blocked fluid port being opened to said tubular housing interior during activation of said first sealing means; and 
 (vi) second activation means responsive to fluid pressure in excess of the pressure required to activate the second sealing mechanism to isolate the said selected first zone from the well bore upstream of said selected first zone and thereafter, upon application of additional pressure within the tubular housing, to fully open said treatment port for transmission of a treating fluid within said tubular housing and into said selected first zone; 
 
   (b) increasing pressure in said tubular workstring and said tubular housing to a first level of fluid pressure to manipulate said first full bore valving mechanism to closed position and to simultaneously open said port;   (c) further increasing pressure in said tubular workstring and said tubular housing above the first level of pressure to activate the first sealing mechanism to set said sealing mechanism in the well and to simultaneously unblock and open said blocked fluid port;   (d) further increasing pressure in said tubular workstring and said tubular housing to activate the second sealing mechanism to sealing position in the well to isolate the said selected first zone from the wellbore upstream of said selected first zone; and   (e) further increasing fluid pressure in the tubular workstring and said tubular housing to fully open the treatment port for transmission of a treating fluid within said tubular housing and into said selected first zone.