Inflatable packer and control valve

Abstract

An inflatable packer and control valve ( 10 ) for use on the outside of a casing ( 23 ), as used in wells and boreholes, and is operated by differential pressure against shear pins ( 126 a, 196 ) and changes operating conditions by axial displacement of generally cylindrical sleeve valve members ( 84, 88 ) in a control valve ( 16 ). The control valve ( 16 ) uses relatively large annular flow passageways ( 140, 260, 310 ) for the flow of inflation fluid, especially cementitious slurries, to avoid blockage and allow reliable inflation and thus minimise the risk of under-inflation due to blockage of tubular passageways commonly used in prior art control valves. The control valve ( 16 ) also uses a locking mechanism ( 90, 272 ) to ensure positive engagement of a shut-in sleeve valve member ( 88 ) to ensure shut-in of the valve ( 88 ) to maintain inflation of the Inflatable packer ( 14 ).

1  to  4 . (canceled) 
     
     
         5 . A single-shot inflatable packer and control valve assembly for use in permanently sealing an annular space between a casing and a borehole surrounding the casing, the assembly including:
 a mandrel having
 threaded ends to connect in-line with the casing; 
 a plurality of radial inlet ports to communicate inflation fluid from the interior to the exterior of the mandrel; and 
 an annular recess located proximate the upstream end of the mandrel; 
 wherein the mandrel is made in a single piece, has a substantially uniform cross-section and has a wall thickness substantially the same as that of the casing; 
   a control valve located on the outer curved surface of the mandrel overlying the radial inlet ports and the annular recess, the control valve having:
 a housing fixed onto the outer curved surface of the mandrel with a retaining ring secured into the annular recess, the housing defining a substantially annular flow passage with the mandrel, wherein the annular flow passage extends substantially along the length of the housing and is in fluidic communication with the radial inlet ports; 
 a first sleeve valve disposed in an upstream portion of the annular flow passage and overlying the radial inlet ports to control flow of inflation fluid into the annular flow passage from the casing, the first sleeve valve being slideable with respect to a longitudinal axis of the mandrel from a closed condition, wherein the first sleeve valve blocks flow of inflation fluid from the plurality of radial inlet ports into the annular flow passage, to an open condition, wherein the pressure differential of the inflation fluid across the first sleeve valve exceeds a first pressure differential causing movement of the first sleeve valve to allow the inflation fluid to flow from the plurality of radial inlet ports into the annular flow passage; 
 a first shearable means securing the first sleeve valve to the housing, the first shearable means being shearable at a pressure above the first pressure differential, wherein the first shearable means permits movement of the first sleeve valve to allow flow of inflation fluid through the said radial inlet ports into the annular flow passage; 
 a second sleeve valve disposed in an downstream portion of the annular flow passage, the second sleeve valve being slideable with respect to the axis of the mandrel from an open condition, wherein inflation fluid is allowed to flow through the annular flow passage, to a closed condition, wherein the pressure differential of the inflation fluid across the second sleeve valve exceeds a second predetermined pressure differential causing movement of the second sleeve valve to prevent flow of inflation fluid through the annular flow passage; 
 a second shearable means securing the second sleeve valve to the housing, the second shearable means being shearable at a pressure above the second pressure differential, wherein the second shearable means allows movement of the second sleeve valve in the annular flow passage to prevent flow of inflation fluid through the annular flow passage for pressures above the second pressure differential; 
 a non-release locking means in operative association with the second sleeve valve, the locking means preventing movement of the second sleeve valve when the second sleeve valve is in its closed condition, the locking means having locking elements with curvilinear faces that engage with each other, the faces permitting movement of the locking elements in one direction only subject to the application of a driving force sufficient to overcome the force of engagement of said locking elements; and 
   an inflatable packer disposed on the outer curved surface of the mandrel and attached to the control valve, the inflatable packer having:
 a fixed end having an inlet port in fluidic communication with the said annular flow passage, the fixed end being attached to the control valve; 
 an inflatable element attached to the fixed end and inflatable with said inflation fluid; and 
 a sliding end attached to the inflatable element opposite the fixed end and disposed downstream thereof, the sliding end being able to move longitudinally along the mandrel; 
 wherein inflation of the inflatable packer is controlled by the control valve to seal off said annular space. 
   
     
     
         6 . An inflatable packer and control valve assembly according to  claim 5 , in which the housing has a shoulder oriented to meet with a shoulder of the second sleeve valve, wherein the engagement of the shoulders limit the movement of said second sleeve valve in its closed condition. 
     
     
         7 . An inflatable packer and control valve assembly according to  claim 5 , in which the non-release locking means includes a ratchet mechanism permitting movement of the second sleeve valve only towards the inflatable packer. 
     
     
         8 . An inflatable packer and control valve assembly according to  claim 7 , in which the ratchet mechanism includes an annular female ratchet ring located in a sealed chamber and an annular male ratchet skirt located upon the second sleeve valve and disposed to slide within the annular female ratchet ring, the male ratchet skirt also being located within the said sealed chamber, wherein movement of the annular male ratchet component within the female ratchet ring causes resilient expansion and contraction of said female ratchet ring and wherein the engagement of the faces of said ratchet components resists movement of the male ratchet component out of said female ratchet ring.