Core barrel valve assembly

Abstract

A valve assembly for use in an inner tube member of a core barrel head assembly positionable within a drill string of a drilling apparatus. The valve assembly works using two separate surfaces A and B and a biasing element with a force F S . When hydrostatic pressure is present forces are created on these surfaces: F A and F B . These forces have a direct relationship with pressure, as an increase in pressure will increase the force and vice versa. The surface areas are designed such that: F A >F B +F S , which will maintain the valve closed while under a predetermined fluid pressure, indicating to the driller that the inner tube has landed. When the driller relieves the fluid pressure and the pressure decreases, the force difference between F A , F B and F S decreases until F A <F B +F S , thus opening the valve for drilling.

1 . A valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus, the valve assembly comprising:
 a landing shoulder;   at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;   at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;   at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;   a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure communication port and having a first surface that is influenced in the supply direction by a force F A  from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force F B  from said fluid;   at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,   wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force F B  from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force F A  from the pressurized fluid acting on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element.   
     
     
         2 . The valve assembly according to  claim 1 , wherein, upon a reduction in the supply of pressurized fluid to the closed valve, a pressure force differential decreases between said first and second sides, and the biasing element then urges the valve element to be displaced from said closed position to said open position. 
     
     
         3 . The valve assembly according to  claim 1 , further comprising:
 a locking device for mechanically locking the valve element in its closed position.   
     
     
         4 . The valve assembly according to  claim 3 , wherein the locking device comprises a pressure sleeve mechanically connected to a latch locking mechanism of the inner tube member. 
     
     
         5 . The valve assembly according to  claim 3 , wherein the valve element comprises:
 a valve body comprising the second surface; and   a valve piston comprising:   a piston element comprising the first surface;   a slotted stem linking the piston element to the valve body; and   a pin attached to piston element and projecting radially away from the piston element,   and wherein the locking device comprises:   an upper latch body having a first profiled slot cooperating with the pin, said first slot comprising a main portion extending along an axial direction and a secondary portion extending in a direction transverse and radial to said axial direction; and   a latch retracting case coaxially displaceable with respect to the upper latch body and overlapping over the upper latch body, the latch retracting case having a second profiled slot cooperating with the pin, said second slot comprising a main portion extending along the axial direction and a secondary portion extending in a direction transverse to said axial direction, parallel to the transverse direction in which the secondary portion of the first slot extends, said latch retracting case cooperating with a latch locking mechanism of the inner tube member, such that the valve element is locked and the latch retracting case prevents the latch locking mechanism from engaging with latches of the core barrel head assembly upon displacement of the pin in the secondary portions of the first and second profiled slots.   
     
     
         6 . A method for operating a valve assembly for use in a core barrel head assembly positionable within a drill string of a drilling apparatus driven by pressurized fluid, the valve assembly comprising:
 a landing shoulder;   at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder;   at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder;   at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus;   a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure port and having a first surface that is influenced in the supply direction by a force F A  from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force F B  from said fluid;   at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position,   wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force F B  from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force F A  from the pressurized fluid acting on said first surface and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element,   the method comprising:   supplying the pressurized fluid to the valve element in said closed position whereupon the valve assembly remains closed;   reducing the supply of pressurized fluid to the closed valve assembly; and   allowing a pressure force differential to decrease between said first and second sides, thereby enabling the biasing element to urge the valve element towards the open position, and thereby allowing fluid flow through the at least one upstream fluid flow port.   
     
     
         7 . The method according to  claim 6 , wherein the valve assembly further comprises a locking device for mechanically locking the valve element in said closed position, wherein during supplying the pressurized fluid the valve element is in a mechanically locked closed position, the method further comprising:
 causing the locking device to cease locking the valve element in the closed position after supplying the pressurized fluid and before reducing the supply of pressurized fluid.   
     
     
         8 . The method according to  claim 7 , wherein the locking device comprises a pressure sleeve mechanically connected to a latch locking mechanism of the inner tube member and supplying pressurized fluid further comprises allowing fluid pressure to displace the pressure sleeve and engage a latch lock of the latch locking mechanism. 
     
     
         9 . The method according to  claim 7 , wherein the valve element comprises:
 a valve body comprising the second surface; and   a valve piston comprising:
 a piston element comprising the first surface; 
 a slotted stem linking the piston element to the valve body; and 
 a pin attached to piston element and projecting radially away from the piston element, 
   wherein the locking device comprises:
 an upper latch body having a first profiled slot cooperating with the pin, said first slot comprising a main portion extending along an axial direction and a secondary portion extending in a direction transverse and radial to said axial direction; and 
 a latch retracting case coaxially displaceable with respect to the upper latch body and overlapping over the upper latch body, the latch retracting case having a second profiled slot cooperating with the pin, said second slot comprising a main portion extending along the axial direction and a secondary portion extending in a direction transverse to said axial direction, parallel to the transverse direction in which the secondary portion of the first slot extends, said latch retracting case cooperating with a latch locking mechanism of the inner tube member, such that the valve element is locked and the latch retracting case prevents the latch locking mechanism from engaging with latches of the core barrel head assembly upon displacement of the pin in the secondary portions of the first and second profiled slots, 
   and wherein supplying pressurized fluid further comprises displacing the pin from the secondary portions to the main portions of the first and second profiled slots, upon proper deployment of the latch locking mechanism, thereby allowing axial movement of the pin and valve piston.   
     
     
         10 . A wire line core drill system, comprising:
 a wire line core drill having an inner tube configured to collect core samples,   an outer tube connected to a drill bit, and   a valve assembly situated at the rear end of the inner tube, said valve assembly controlling the supply of a flushing medium in the form of a pressurized fluid, wherein the valve assembly comprises
 a landing shoulder, 
 at least one upstream fluid flow port positionable within a fluid line of the drilling apparatus upstream of the landing shoulder, 
 at least one downstream fluid flow port positionable within the fluid line of the drilling apparatus downstream of the landing shoulder, 
 at least one fluid pressure communication port positionable within the fluid line of the drilling apparatus, 
 a movable valve element having a first side in fluid communication with pressurized fluid through the at least one pressure communication port and having a first surface that is influenced in the supply direction by a force F A  from said fluid, and a second side facing in the opposite direction, in fluid communication with pressurized fluid through the at least one upstream fluid flow port and having a second surface that is influenced in the opposite direction by a force F B  from said fluid, and 
 at least one biasing element for opening the valve assembly by displacing the valve element from a closed position to an open position, 
 wherein the area of said second surface is greater than that of said first surface so that the force influencing the valve element in a closing direction, in the form of the force F B  from the pressurized fluid acting on said second surface exceeds the force influencing the valve element in an opening direction, in a form of combining a force Fs from the biasing element and the force F A  from the pressurized fluid actin on said first surface, whereby the valve element is retained in the closed position of the valve when pressurized fluid is supplied and wherein the at least one fluid pressure communication port and the at least one upstream fluid flow port form two sets of ports, the first set for fluid pressure communication with the movable valve element, and the second set for fluid flow required for drilling in which the fluid flow is blocked or opened by the movable valve element.