Multi-Zone Screened Frac System

Abstract

A multi-zone screened frac system combines screens with integrated check valves, frac valves, and optional shunt tubes for slurry dehydration. The system can also include fiber optic technology. In particular, the system uses sliding sleeves and flow devices for each section. The sliding sleeves open with dropped balls or a service tool, and the flow devices have screens and act as check valves. Dehydration tubes can also be used. The system does not require a crossover tool, and in some implementations, the system does not even require a complete service tool.

1 . A multi-zone frac assembly for a borehole, comprising:
 a tubular structure disposed in the borehole and defining a through-bore; and   a plurality of sections disposed on the tubular structure, each of the sections comprising:
 an isolation element disposed on the tubular structure and isolating a borehole annulus of the section from the other sections, 
 a flow valve disposed on the tubular structure and selectively operable between opened and closed conditions, the flow valve in the opened condition permitting fluid communication between the through-bore and the borehole annulus, the flow valve in the closed condition preventing fluid communication between the through-bore and the borehole annulus, 
 a screen disposed on the tubular structure and communicating with the borehole annulus, and 
 a check valve disposed on the tubular structure and in fluid communication between the screen and the through-bore, the check valve permitting fluid communication from the screen into the through-bore and preventing fluid communication from the through-bore to the screen. 
   
     
     
         2 . The assembly of  claim 1 , wherein the isolation element comprises a swellable packer, a hydraulically-set packer, or a mechanically-set packer. 
     
     
         3 . The assembly of  claim 1 , wherein at least a portion of the tubular structure for a given one of the sections comprises a basepipe having the through-bore and defining at least one pipe port communicating the through-bore outside the basepipe. 
     
     
         4 . The assembly of  claim 1 , wherein the check valve is disposed on the tubular structure adjacent at least one pipe port communicating the through-bore outside the tubular structure, the check valve permitting fluid communication from the screen to the at least one pipe port and preventing fluid communication from the at least one pipe port to the screen. 
     
     
         5 . The assembly of  claim 4 , wherein the check valve comprises a housing disposed on the tubular structure, the housing having at least one internal flow passage and having at least one check ball, the at least one internal flow passage communicating the screen with the at least one pipe port, the at least one check ball movable to one condition permitting fluid communication through the at least one internal flow passage and movable to another condition preventing fluid communication through the at least one internal flow passage. 
     
     
         6 . The assembly of  claim 4 , wherein the screen is disposed on the tubular structure and has one end in fluid communication with the check valve. 
     
     
         7 . The system of  claim 1 , wherein the flow valve comprises:
 a housing having a flow port communicating the through-bore outside the housing; and   an insert movable in the housing between the closed condition preventing fluid communication through the flow port and the opened condition permitting fluid communication through the flow port.   
     
     
         8 . The assembly of  claim 7 , wherein the insert comprises a seat disposed therein, the seat seating a plug deployed in the tubular structure thereon and moving the insert from the closed condition to the opened condition in response to application of fluid pressure against the seated plug. 
     
     
         9 . The assembly of  claim 1 , further comprising a flow tube disposed in the borehole annulus and communicating through the isolation elements between one or more of the sections. 
     
     
         10 . The assembly of  claim 1 , further comprising a workstring disposing in the through-bore of the tubular structure, the workstring operable to open and close the flow valve of each section and operable to seal inside the assembly and place an outlet port on the workstring in sealed communication with the borehole annulus when the flow valve has the opened condition. 
     
     
         11 . The assembly of  claim 10 , wherein the workstring comprises an actuating tool operable to engage the flow valve in one direction and actuate the flow valve open and operable to engage the flow valve in another direction and actuate the flow valve closed. 
     
     
         12 . The assembly of  claim 10 , wherein the assembly comprises seats disposed in the through-bore on both uphole and downhole sides of a flow port in the flow valve, and wherein the workstring comprises seals disposed on both uphole and downhole sides of the outlet port, the seals configured to seal against the seats disposed in the through-bore. 
     
     
         13 . The assembly of  claim 10 , further comprising a bypass tube for at least one of the sections, the bypass tube communicating a first portion of the through-bore on one side of a location of the workstring sealed inside the assembly to another side of the location. 
     
     
         14 . A multi-zone frac assembly for a borehole, comprising:
 a tubular structure disposed in the borehole and defining a through-bore; and   a plurality of sections disposed on the tubular structure, each of the sections comprising:
 means for isolating a borehole annulus of the section from the other sections, 
 means for selectively permitting and preventing fluid communication between the through-bore and the borehole annulus through a first flow path, 
 means for exclusively screening fluid communication from the borehole annulus to the through-bore through a second flow path, and 
 means for exclusively preventing fluid communication from the through-bore to the borehole annulus through the second flow path. 
   
     
     
         15 . The assembly of  claim 14 , wherein the means for selectively permitting and preventing fluid communication between the through-bore and the borehole annulus through the first flow path comprises means for selectively opening and closing ports in the tubular structure. 
     
     
         16 . The assembly of  claim 14 , wherein the means for exclusively screening fluid communication from the borehole annulus to the through-bore through the second flow path comprises means for permitting fluid communication of the screened fluid into the through-bore through the second flow path. 
     
     
         17 . A multi-zone frac method for a borehole, the method comprising:
 disposing the assembly in the borehole;   isolating an annulus of the borehole around the assembly into a plurality of isolated zones;   screening fluid communication from the annulus of the isolated zones into a through-bore of the assembly with screens on the assembly;   preventing fluid communication from the through-bore to the annulus of the isolated zones through the screens; and   treating each of the isolated zones with a treatment fluid by:
 selectively opening a port in the assembly at the each isolated zone, and 
 flowing the treatment fluid down the through-bore to the each isolated zone through the opened port. 
   
     
     
         18 . The method of  claim 17 , wherein disposing the assembly in the borehole comprises disposing the assembly in casing having perforations, in an expanded liner having slots, or in an open hole. 
     
     
         19 . The method of  claim 18 , wherein isolating the annulus of the borehole around the assembly into the isolated zones comprises engaging packing elements on the assembly against a wall of the casing, a wall of the expanded liner, or a wall of the open hole. 
     
     
         20 . The method of  claim 17 , wherein screening fluid from the annulus of the isolated zones into the through-bore of the assembly with screens on the assembly comprises allowing fluid communication from the screens through perforations in the assembly communicating with the through-bore. 
     
     
         21 . The method of  claim 20 , wherein preventing fluid communication from the through-bore to the annulus of the isolated zones through the screens comprises disposing a check valve in fluid communication between the screens and the perforations. 
     
     
         22 . The method of  claim 17 , wherein selectively opening the port in the assembly at the each isolated zone comprises opening the port in the assembly by moving an insert in the assembly away from the port. 
     
     
         23 . The method of  claim 22 , further comprising selectively closing the opened ports in the assembly at each of the isolated zones. 
     
     
         24 . The method of  claim 22 , wherein moving the insert in the assembly away from the port comprises:
 engaging a plug on the insert; and   moving the insert away from the port with application of fluid pressure against the engaged plug.   
     
     
         25 . The method of  claim 24 , wherein flowing the treatment fluid down the through-bore to the each isolated zone through the opened port comprises flowing the treatment fluid through the opened port when the insert is moved away from the port. 
     
     
         26 . The method of  claim 24 , wherein treating each of the isolated zones with the treatment fluid comprises:
 successively treating the isolated zones uphole on the assembly by successively engaging plugs and moving inserts uphole on the assembly for successive ones of the isolated zones.   
     
     
         27 . The method of  claim 24 , further comprising:
 removing the engaged plug; and   selectively closing the insert over the opened port in the assembly.   
     
     
         28 . The method of  claim 22 , wherein moving the insert in the assembly away from the port comprises:
 engaging the insert with a workstring disposed in the through-bore of the assembly; and   moving the insert away from the port with movement of the engaged workstring.   
     
     
         29 . The method of  claim 28 , wherein flowing the treatment fluid down the through-bore to the each isolated zone through the opened port comprises flowing the treatment fluid through an outlet in the workstring and through the opened port when the insert is moved away from the port. 
     
     
         30 . The method of  claim 28 , wherein treating each of the isolated zones with the treatment fluid comprises:
 successively closing a given one of the inserts with the workstring after treatment; and   successively opening another one of the inserts with the workstring before treatment.