Method and system for gravel packing a borehole

Abstract

A downhole system including a packer between sand screens, a service string having an annular seal bridging between the service string and the packer, a sensor uphole of the seal to detect a parameter and a sensor downhole of the seal to detect a parameter, a valve openable in response to a differential detected in the parameter between the sensor uphole of the seal and the sensor downhole of the seal; wherein the packer is settable in response to the same detected differential. A method for packing a borehole.

What is claimed is: 
     
         1 . A downhole system comprising:
 a packer between sand screens;
 a service string having an annular seal bridging between the service string and the packer; 
 a sensor uphole of the seal to detect a parameter and a sensor downhole of the seal to detect a parameter; 
 a valve openable in response to a differential detected in the parameter between the sensor uphole of the seal and the sensor downhole of the seal; wherein the packer is settable in response to the same detected differential. 
   
     
     
         2 . The downhole system as claimed in  claim 1  wherein the differential detected is pressure. 
     
     
         3 . The downhole system as claimed in  claim 1  wherein the packer is triggered to set when the differential is that the pressure uphole of the seal is higher than the pressure downhole of the seal. 
     
     
         4 . The downhole system as claimed in  claim 1  wherein the packer is a hydraulically set compression packer. 
     
     
         5 . The downhole system as claimed in  claim 1  wherein the packer is triggered electrically. 
     
     
         6 . The downhole system as claimed in  claim 1  wherein the valve is uphole of the seal. 
     
     
         7 . The downhole system as claimed in  claim 1  wherein the system includes an alternate path for slurry flow. 
     
     
         8 . The downhole system as claimed in  claim 7  wherein the alternate path for slurry flow is eccentric. 
     
     
         9 . A method for packing a borehole comprising:
 flowing a gravel slurry to an area of a borehole that includes a packer, a screen downhole of the packer and a screen uphole of the packer and a service string disposed within and sealed to the packer by an annular seal;   depositing gravel from the gravel slurry in an alpha wave and a beta wave;   sensing a parameter uphole of the seal and downhole of the seal;   triggering setting of the packer upon a selected differential in the sensed parameter uphole and downhole of the seal.   
     
     
         10 . The method as claimed in  claim 9  wherein the parameter is pressure. 
     
     
         11 . The method as claimed in  claim 9  wherein the triggering includes hydraulically setting the packer. 
     
     
         12 . The method as claimed in  claim 9  wherein the triggering is electrical. 
     
     
         13 . A method for packing a borehole comprising:
 flowing slurry into a borehole;   sanding out a screen downhole of a packer;   sensing a parameter on each longitudinal end of an annular seal sealed between the packer and a service string;   triggering setting of the packer upon sensing a selected differential in the parameter on each longitudinal end of the annular seal.   
     
     
         14 . The method as claimed in  claim 13  further comprising opening a valve after sand out of the screen to promote gravel packing of a next adjacent screen. 
     
     
         15 . The method as claimed in  claim 14  wherein the opening is triggered by the same selected differential. 
     
     
         16 . The method as claimed in  claim 13  wherein the differential is of pressure. 
     
     
         17 . A downhole system comprising:
 a packer between sand screens;
 a service string having an annular seal bridging between the service string and the packer; 
 a valve openable in response to a differential detected across the annular seal; wherein the packer is settable in response to the same detected differential.