Apparatus and method for obtaining a core at in situ pressure
First Claim
1. Apparatus for obtaining a core at in situ pressure of the sedimentary deposits at the bottom of a well bore, a body of water or the like comprising a tubular housing adapted to be moved into position above the sedimentary deposits to be cored, a pressure chamber in the lower section of the housing, a sample tube located in the pressure chamber, valve means at the lower end of the pressure chamber to open and close the chamber to ambient conditions, means actuated from the surface for moving the sample tube through the open valve to force the sample tube into the sedimentary deposits to obtain a core of said deposits and to move the sample tube with the core back into the pressure chamber in the housing, means for closing the valve means to seal the pressure chamber from ambient conditions before the housing is removed from its position above the sedimentary deposits being cored to maintain substantially the in situ pressure of the core in the pressure chamber.
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Accused Products
Abstract
A method and apparatus are disclosed for obtaining a core at in situ pressure of sedimentary deposits at the bottom of a well bore or body of water. The core barrel has a pressure chamber that is closed and opened by a ball valve actuated from the surface. When in position above the sedimentary deposits to be cored, a sample tube is extended from the pressure chamber into the sedimentary deposits to obtain a core. The sample tube is retracted into the pressure chamber and the valve closed to trap ambient pressure in the chamber. The sample tube and valve are operated from the surface.
50 Citations
19 Claims
- 1. Apparatus for obtaining a core at in situ pressure of the sedimentary deposits at the bottom of a well bore, a body of water or the like comprising a tubular housing adapted to be moved into position above the sedimentary deposits to be cored, a pressure chamber in the lower section of the housing, a sample tube located in the pressure chamber, valve means at the lower end of the pressure chamber to open and close the chamber to ambient conditions, means actuated from the surface for moving the sample tube through the open valve to force the sample tube into the sedimentary deposits to obtain a core of said deposits and to move the sample tube with the core back into the pressure chamber in the housing, means for closing the valve means to seal the pressure chamber from ambient conditions before the housing is removed from its position above the sedimentary deposits being cored to maintain substantially the in situ pressure of the core in the pressure chamber.
- 6. Apparatus for recovering a core of the sedimentary deposits at the bottom of a well bore at its in situ pressure comprising a tubular housing adapted to be moved to the bottom of a well bore through a pipe string, a pressure chamber in the lower section of the housing, a sample tube located in the pressure chamber, valve means at the lower end of the pressure chamber to open and close the chamber to ambient conditions, means actuated from the surface for moving the sample tube through the open valve when the housing is located at the bottom of the pipe string to force the sample tube into the sedimentary deposits at the bottom of the well bore to obtain a core of said deposits and to move the sample tube with the core back into the pressure chamber in the housing, means for closing the valve means to seal the pressure chamber from ambient conditions before the housing is removed from its position at the lower end of the drill pipe to maintain the in situ pressure of the core in the pressure chamber while the core is being moved through the pipe string to the surface.
- 13. Apparatus for obtaining a core at in situ pressure of the sedimentary deposits at the bottom of a well bore or a body of water comprising a tubular housing adapted to be moved into position above the sedimentary deposits to be cored, a pressure chamber in the lower section of the housing, a sample tube located in the pressure chamber, valve means at the lower end of the pressure chamber to open and close the chamber to ambient conditions, said valve means including a valve member comprising a ball with hole through it and a lower valve seat positioned below the ball to engage the ball and seal the pressure chamber when the ball is in its closed position, means actuated from the surface for moving the sample tube through the open valve when the housing is located at the bottom of the pipe string to force the sample tube into the sedimentary deposits at the bottom of the well bore to obtain a core of said deposits and to move the sample tube with the core back into the pressure chamber in the housing, means for closing the valve means to seal the pressure chamber from ambient conditions before the housing is removed from its position at the lower end of the drill pipe to maintain the in situ pressure of the core in the pressure chamber while the core is being moved through the pipe string to the surface, said means including an upper seat of elastomeric material located above the ball, means limiting the upward movement of the upper seat away from the lower seat, and means for exerting an upward eccentric force on the ball to move the ball away from the lower seat into engagement with the upper seat to rotate the ball to its closed position.
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16. A method of obtaining a core at in situ pressure from the sedimentary deposits at the bottom of a well bore, a body of water or the like comprising the steps of lowering a housing having a valve in the lower end thereof to a position above the sedimentary deposits, extending an open-ended sample tube from the housing through the open valve into the sedimentary deposits to force a core of the deposits into the sample tube, retracting the sample tube with the core therein into the housing above the valve, moving the valve element of the valve to its closed position, exerting a downward force on the valve element to hold the valve element in sealing engagement with the seat to seal the bottom of the housing below the sample tube to trap ambient pressure in the housing around the sample tube, and raising the housing to the surface.
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17. A method of obtaining a core at in situ pressure from the sedimentary deposits at the bottom of a bore hole comprising the steps of positioning a pipe string in the well bore with an opening in its lower end, lowering a housing through the pipe string to a position adjacent the bottom of the well bore, extending an open-ended core tube from the housing into the sedimentary deposits at the bottom of the well bore to force a core of the deposits into the core tube, retracting the core tube with the core therein into the housing, purging the housing of ambient fluid, sealing the bottom of the housing below the core tube to trap in situ pressure in the housing around the core tube, and raising the housing to the surface.
- 18. A method of obtaining a core at in situ pressure from the sedimentary deposits at the bottom of a bore hole comprising the steps of positioning a pipe string in the well bore with an opening in its lower end, lowering a housing having a ball valve in the lower end thereof through the pipe string to a position adjacent the bottom of the well bore, extending an open-ended core tube from the housing through the ball valve into the sedimentary deposits at the bottom of the well bore to force a core of the deposits into the sample tube, retracting the core tube with the core therein into the housing above the ball valve, purging the housing of ambient fluid, raising the ball of the ball valve from its seat, rotating the ball to its closed position, lowering the ball into engagement with the seat, exerting a downward force on the ball to hold the ball in sealing engagement with the seat to seal the bottom of the housing below the core tube to trap in situ pressure in the housing around the core tube, raising the housing to the surface, and transferring the core tube from the housing to a transfer tube while maintaining the core at in situ pressure.
Specification