Downhole Fluid Treatment Tool

Abstract

A treatment device and method for use in delivering fluid treatment to a wellbore is described. The device includes a first treatment housing and a second treatment housing, mounted along a tubing string, each of the first and second housing defining a fluid pathway which is continuous with the tubing string and each of the first and second treatment housing defining a port for fluid communication between the tubing string and the wellbore. Fluid flow through the first housing may be selectively blocked by delivery of a deformable ball to the tubing string to seal against a ball seat disposed between the first and second housing. While the first pathway is blocked, fluid may be selectively delivered to the wellbore through the port on the second treatment housing. The ball may be removed from the ball seat by application of hydraulic pressure in excess of the deformation threshold of the ball, forcing the ball to deform and pass through the seat, re-opening the fluid flow through the first treatment housing and allowing for treatment through port defined in the first housing.

What is claimed is: 
     
         1 . A downhole treatment assembly, the assembly comprising:
 a first housing disposed on a tubing string, the first housing defining a first fluid pathway continuous with the tubing string and including a wall defining a first port for passage of fluid between the first fluid pathway and the wellbore;   a second housing disposed on the tubing string above the first housing, the second housing defining a second fluid pathway continuous with the tubing string and with the first fluid pathway, the wall of the second housing including a second port through which fluid can flow from the tubing string to the wellbore; and   a ball valve disposed on the tubing string between the first port and the second port, the ball valve comprising a ball seat at the upper end of the valve, the ball seat configured to receive a deformable ball, and a ball trap for preventing unseated, deformed balls from re-entering the ball valve.   
     
     
         2 . The assembly of  claim 1 , wherein the ball valve is mounted within the first housing above the first port. 
     
     
         3 . The assembly of  claim 1 , wherein the second housing comprises a jet perforation device and the second port comprises a jet nozzle. 
     
     
         4 . The assembly of  claim 1 , wherein the ball valve is provided as a removable insert in the first housing. 
     
     
         5 . A system for wellbore treatment, the system comprising:
 a first housing disposed on a tubing string, the first housing defining a first fluid pathway continuous with the tubing string;   a first port defined in the first housing for lateral fluid flow from the first fluid pathway to the wellbore;   a second housing disposed on the tubing string above the first housing, the second housing defining a second fluid pathway continuous with the tubing string and with the first fluid pathway;   a second port defined in the second housing for fluid communication between the second fluid pathway into the wellbore;   a ball valve disposed the tubing string between the first port and the second flow port, the ball valve adapted to receive a deformable ball, wherein when seated the ball prevents fluid flow through the fluid pathway of the first housing; and   a sealing device deployed on the tubing string below the first housing, the sealing device for sealingly engaging the wellbore and thereby defining a wellbore interval to be treated above the sealing device.   
     
     
         6 . The system of  claim 5 , wherein the ball valve is disposed within the first housing above the first port. 
     
     
         7 . The system of  claim 5 , wherein the second housing comprises a jet perforation device and the lateral port is a jet perforation nozzle. 
     
     
         8 . A method of selectively treating a wellbore, the method comprising:
 deploying a tool assembly on a tubing string into a wellbore, the tool assembly comprising a first housing and a second housing, the first and second housing being fluidically continuous with the tubing string and the first and second housing each having a fluid port for fluid communication from the tubing string to the wellbore, and a ball valve between the ports of the first and second housing, the ball valve comprising a ball seat for receiving a deformable ball having a pressure deformation threshold;   delivering fluid to through the tubing string to the first housing to effect a wellbore treatment through the port of the first housing;   dropping the deformable ball through the tubing string to land on the ball seat, thereby blocking fluid flow from the tubing string to the first housing;   continuing to deliver fluid to the tubing string while the ball remains seated in the valve seat; and   increasing the pressure differential across the ball seat to exceed the pressure deformation threshold of the ball, thereby unseating the ball from the ball seat so that fluid can flow through the first housing.   
     
     
         9 . The method of  claim 8 , further comprising delivering fluid to the tubing string to effect fluid treatment through the port of the first housing once the ball is unseated. 
     
     
         10 . The method of  claim 8 , further comprising passing the ball through a lower end of the ball valve to a region within the first housing after the ball has been deformed. 
     
     
         11 . The method of  claim 8 , further comprising delivering fluid suitable for fracturing prior to seating the ball and delivering fluid suitable for sand jet perforation after seating the ball. 
     
     
         12 . The method of  claim 8 , further comprising sealing the tubing string in the wellbore below the first housing prior to fluid delivery down the tubing string. 
     
     
         13 . A method for selective delivery of treatment fluid from tubing string to a wellbore, the method comprising the steps of:
 deploying a tool assembly within a wellbore on tubing string, the tool assembly comprising a first housing and a second housing, the first and second housing being fluidically continuous with the tubing string and the first and second housing each having a fluid port for fluid communication from the tubing string to the wellbore, and a ball valve between the ports of the first and second housing, the ball valve comprising a ball seat for receiving a deformable ball having a pressure deformation threshold;   delivering treatment fluid through a tubing string to effect treatment of the wellbore through the port of the first housing;   delivering a ball to the tubing string, the ball of suitable size to seal against the ball seat;   seating the ball against the ball seat;   continuing to deliver fluid to the tubing string to effect fluid treatment of the wellbore through the port of the second housing;   delivering fluid treatment to the wellbore annulus at a rate suitable to reverse circulate the ball to surface through the tubing string; and   delivering fluid to the tubing string to effect fluid treatment through the port of the first housing.   
     
     
         14 . The method of  claim 13 , wherein the second fluid treatment housing is a jet perforation device. 
     
     
         15 . The method of  claim 13 , wherein treatment through the first treatment pathway comprises fracturing. 
     
     
         16 . The method of  claim 13 , further comprising the steps of setting a sealing device against the annulus defined between the tubing string and the wellbore prior to delivering the ball and unsetting the sealing device prior to reverse circulation.