Debris removal system and method for pressure controlled wellbore drilling and intervention operations

Abstract

A wellbore debris screening system used with controlled annulus pressure wellbore intervention and drilling operations includes a wellbore annulus seal configured to pressure isolate an annular space between a conduit inserted into the wellbore and the wellbore wall. A first screening device is coupled to an output of the annulus seal. second screening device is coupled to the output of the annulus seal. Valves are provided that are operable to selectively divert flow out of the annulus to the first and to the second screening sections.

1 . A wellbore debris screening system used with controlled annulus pressure wellbore intervention and drilling operations, comprising:
 a wellbore annulus seal configured to pressure isolate an annular space between a conduit inserted into the wellbore and the wellbore wall;   a first screening section coupled to an output of the annulus seal;   a second screening device coupled to the output of the annulus seal; and   valves operable to selectively divert flow out of the annulus to the first and to the second screening sections.   
     
     
         2 . The system of  claim 1  further comprising pressure sensors in hydraulic communication with an intake side and an outlet side of each of the first and second screening sections. 
     
     
         3 . The system of  claim 1  further comprising a bypass line coupled between the output of the annulus seal and an outlet manifold coupled to outlet side of the first and second screening sections. 
     
     
         4 . The system of  claim 1  further comprising a controllable orifice choke disposed between the outlet manifold and a pressure tank, the choke operable to maintain a selected pressure in the wellbore annulus. 
     
     
         5 . The system of  claim 1  wherein each screening section includes valves at its inlet and outlet to enable removal from the system while maintaining fluid pressure within the screening section. 
     
     
         6 . The system of  claim 1  further comprising sensors associated with each screening section, the sensors selected and arranged to enable at least one of characterization of debris particle size, debris particle shape, presence of water, oil, gas and fractional amounts thereof. 
     
     
         7 . The system of  claim 3  further comprising a pressure actuated burst disk disposed in either of the screening sections or the bypass line. 
     
     
         8 . The system of  claim 1  wherein screens in each screening section comprise at least two mesh sizes. 
     
     
         9 . A method for collecting debris from a wellbore during wellbore intervention operations, comprising:
 circulating fluid through the interior of a pipe disposed in the wellbore to conduct the intervention operations;   returning the fluid up an annular space between a wall of the wellbore and an exterior of the pipe;   maintaining a fluid seal at the surface between the annular space and the pipe;   discharging the fluid from below the fluid seal to at least two parallel-connected, pressure sealed screening devices, the discharging performed so that the fluid flows only through a first one of the at least two screening devices; and   when the first one of the screening devices is determined to be full, diverting flow to a second one of the at least two screening devices.   
     
     
         10 . The method of  claim 9  wherein determining when the first one of the screening devices is full comprises measuring a pressure drop between and inlet and outlet of the first one of the screening devices. 
     
     
         11 . The method of  claim 9  further comprising hydraulically isolating the first one of the screening devices and removing it from any hydraulic circuit including the at least two screening devices. 
     
     
         12 . The method of  claim 9  further comprising bypassing flow of fluid around the at least two screening devices if at least one of the screening devices become clogged and debris samples are not needed at selected times. 
     
     
         13 . The method of  claim 9  further comprising sensing selected parameters of the fluid moving through the at least to screening devices to determine at least one of debris particle size, debris particle shape, and fluid composition. 
     
     
         14 . The method of  claim 9  further comprising automatically dumping one of the at least two screening sections at selected times and recording a depth of the pipe in the wellbore at the selected times.