Variable annular valve network for well operations

Abstract

A method and system for creating a multi-gradient pressure regime within a wellbore annulus. A plurality of valve subs provided along a drill string with each sub including a port for selectively venting supply fluid from the drill string to the annulus. A valve is coupled to the port to control the supply fluid flow into the annulus. The valve has a stator fixed in relation to the valve sub housing. A rotor is in sealing contact with the stator, the rotor being rotatable with respect to the stator. The stator and rotor each have apertures formed therethrough, so that the rotor may be oriented between a fully shut position in which the stator and rotor apertures are not in alignment and a fully open position in which the stator and rotor apertures are in maximum alignment. The valve allows precise metering between the fully open and shut positions.

What is claimed: 
     
         1 . A valve sub for use along a drill string within a wellbore, comprising:
 a tubular housing;   a port formed through a wall of said housing fluidly coupling an interior of said housing to an exterior of said housing;   a valve coupled to said port disposed so as to control a fluid flow through said port, said valve having a stator fixed in relation to said housing with a stator aperture formed therethrough and a rotor in sealing contact with said stator with a rotor aperture formed therethrough, said rotor being rotatable with respect to said stator between a fully shut position in which said stator aperture and said rotor aperture are not in alignment and a fully open position in which said stator aperture and said rotor aperture are in maximum alignment; and   a valve sub controller coupled to said valve operable to control an orientation of said rotor with respect to said stator.   
     
     
         2 . The valve sub of  claim 1  further comprising:
 an actuator mounted to said housing and coupled between said rotor and said valve sub controller so as to selectively rotate said rotor with respect to said stator. 
 
     
     
         3 . The valve sub of  claim 1  further comprising:
 a sensor mounted to said housing and coupled to said valve sub controller. 
 
     
     
         4 . The valve sub of  claim 1  further comprising:
 a generator mounted to said housing and coupled to said valve sub controller, said generator arranged to generate electrical power from a fluid flow through said interior of said housing. 
 
     
     
         5 . The valve sub of  claim 4  further comprising:
 a turbine disposed in said interior of said housing and coupled to said generator for turning said generator. 
 
     
     
         6 . The valve sub of  claim 5  wherein:
 said turbine is coupled to said valve sub controller and arranged for providing a signal proportional to said fluid flow through said interior of said housing. 
 
     
     
         7 . The valve sub of  claim 1  further comprising:
 a transmitter/receiver mounted to said housing and coupled to said valve sub controller. 
 
     
     
         8 . The valve sub of  claim 1  wherein:
 said stator includes first and second stator apertures each having an arcuate teardrop shape; and 
 said rotor includes first and second rotor apertures each having an arcuate teardrop shape. 
 
     
     
         9 . The valve sub of  claim 8  wherein:
 said stator has a generally planar surface; and 
 said rotor has a generally planar surface. 
 
     
     
         10 . A system for use within a wellbore, comprising:
 a rig;   a drill string extending from said rig;   at least two valve subs disposed along said drill string, each said valve sub having a tubular housing defining an interior that is fluidly coupled with an interior of said drill string;   a port formed through the housing of each said valve sub, each said port fluidly coupling said interior of said drill string to an exterior of said drill string; and   a valve coupled to each said port, respectively, so as to selectively control fluid flow through said port, each said valve having a stator with a stator aperture formed therethrough and a rotor in sealing contact with said stator with a rotor aperture formed therethrough, said rotor being rotatable with respect to said stator between a fully shut position in which said stator aperture and said rotor aperture are not aligned and a fully open position in which said stator aperture and said rotor aperture are maximally aligned.   
     
     
         11 . The system of  claim 10  further comprising:
 at least one valve sub controller and at least actuator coupled to each said valve and operable to control an orientation of said rotor with respect to said stator of each said valve. 
 
     
     
         12 . The system sub of  claim 11  further comprising:
 at least one sensor coupled to said at least one valve sub controller. 
 
     
     
         13 . The system of  claim 11  further comprising:
 at least one generator coupled to said at least one valve sub controller, said at least one generator arranged to generate electrical power from a fluid flow through said interior of said drill string. 
 
     
     
         14 . The system of  claim 13  further comprising:
 at least one turbine coupled to said at least one generator for turning said at least one generator. 
 
     
     
         15 . The system of  claim 14  wherein:
 said at least one turbine is coupled to said at least one valve sub controller and arranged for providing a signal proportional to said fluid flow through said interior of said drill string. 
 
     
     
         16 . The system of  claim 10  further comprising:
 an actuator coupled to each said valve and operable to position said rotor with respect to said stator of each said valve; 
 a valve sub controller coupled to each said actuator and operable to control each said actuator; 
 a transmitter/receiver coupled to each said valve sub controller, the transmitter/receiver of a first valve sub controller operable to communicate with said transmitter/receiver of a second valve sub controller; and 
 a pressure sensor carrier coupled to each said valve sub controller. 
 
     
     
         17 . The system of  claim 16  further comprising:
 a central controller coupled to said valve sub controllers. 
 
     
     
         18 . The system of  claim 16  further comprising:
 a pumping system fluidly coupled to said drill string and in communication with at least one said valve sub controller, said at least one said valve sub controller operable to control said pumping system; and 
 a supply fluid tank fluidly coupled to said pump. 
 
     
     
         19 . The system of  claim 10  wherein:
 the stator of each of said first and second valves includes first and second stator apertures each having an arcuate teardrop shape; and 
 the rotor of each of said first and second valves includes first and second rotor apertures each having an arcuate teardrop shape. 
 
     
     
         20 . The system sub of  claim 19  wherein:
 the stator of each of said first and second valves has a generally planar surface; and 
 the rotor of each of said first and second valves has a generally planar surface. 
 
     
     
         21 . A method for creating a multi-gradient pressure within a wellbore annulus, comprising:
 determining a measured pressure gradient within said wellbore by measuring annular pressure within a wellbore at a first depth and at a second depth different than the first depth; and   actuating a first valve release supply fluid from a drill string into the wellbore annulus, wherein fluid flow through the first valve is selectively controlled by rotating a rotor relative to a stator to permit the supply fluid to pass through an aperture into the wellbore annulus.   
     
     
         22 . The method of  claim 21  wherein:
 at least said measured annular pressure at the first and second depths define a measured pressure set. 
 
     
     
         23 . The method of  claim 21  wherein:
 said first valve is located at said first depth; and 
 actuating said first valve results in an adjusted pressure gradient in said wellbore that is different that said measured pressure gradient. 
 
     
     
         24 . The method of  claim 23  further comprising:
 actuating a second valve at the second depth to release supply fluid from said drill string into the wellbore annulus, wherein fluid flow through the valve is selectively controlled by rotating a rotor relative to a stator to permit the supply fluid to pass through an aperture into the wellbore annulus. 
 
     
     
         25 . The method of  claim 22  further comprising:
 creating an expected pressure set along at least a portion of said wellbore annulus; 
 determining a calculated pressure gradient from the expected pressure set; 
 comparing the measured pressure gradient to the calculated pressure gradient; and 
 actuating said first valve based on the comparison of the measured pressure gradient to the calculated pressure gradient. 
 
     
     
         26 . The method of  claim 25  further comprising:
 determining a downhole condition based on the comparison of the measured pressure gradient to the calculated pressure gradient; and 
 identifying a location of said downhole condition based on the comparison of the measured pressure gradient to the calculated pressure gradient. 
 
     
     
         27 . The method of  claim 25  further comprising:
 modifying the expected pressure set based on actuating said first valve.