Downhole core barrel flushing system
First Claim
1. A core barrel flushing device adapted for attachment to a drill string and a core barrel to be flushed under existing downhole core sample taking conditions and pressure comprising:
- an outer barrel,an inner barrel within the outer barrel and having an internal passage for allowing drilling fluid to pass therethrough to the core barrel,a chamber of predetermined axial length and volume within the outer barrel and having an entrance end portion and an opposite exit end portion,a piston movable in the chamber, relative to the inner and outer barrels,a flushing medium of sufficient predetermined volume in the chamber between the piston and the exit end of the chamber,seal means at the entrance and exit end portions of the chamber adapted for sealing off the chamber, andactuating means for closing off the internal passage and flow of drilling fluid therethrough, providing an entrance passage for fluid under pressure to act upon and displace the piston, and an exit passage for the flushing medium displaced by the piston into and flush the core barrel downhole.
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Accused Products
Abstract
A core barrel flushing device and method is disclosed particularly for flushing drilling fluid, mud and other undesirable material from a pressure core barrel downhole at existing conditions and pressure.
The flushing device (F) comprises an outer barrel attachable to the drill string and core barrel (10), and an inner barrel (90) within the outer barrel (70). A sealed chamber (C) within the outer barrel (70) contains a piston (114) and flushing medium (M) displacable from the chamber (C) and into the core barrel during forceful displacement of the piston following actuation of the flushing device.
Actuation of the flushing device is initiated by means (B) passed down the drill string into engagement with actuating means (94) allowing displacement of the piston and flushing medium from the chamber into the core barrel.
Tripping means (112) are also disclosed responsive to the final movement of the piston to actuate, and seal the flushed pressure core barrel (10) and core sample (51) therein downhole.
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Citations
15 Claims
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1. A core barrel flushing device adapted for attachment to a drill string and a core barrel to be flushed under existing downhole core sample taking conditions and pressure comprising:
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an outer barrel, an inner barrel within the outer barrel and having an internal passage for allowing drilling fluid to pass therethrough to the core barrel, a chamber of predetermined axial length and volume within the outer barrel and having an entrance end portion and an opposite exit end portion, a piston movable in the chamber, relative to the inner and outer barrels, a flushing medium of sufficient predetermined volume in the chamber between the piston and the exit end of the chamber, seal means at the entrance and exit end portions of the chamber adapted for sealing off the chamber, and actuating means for closing off the internal passage and flow of drilling fluid therethrough, providing an entrance passage for fluid under pressure to act upon and displace the piston, and an exit passage for the flushing medium displaced by the piston into and flush the core barrel downhole. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of flushing a core barrel downhole at existing conditions and pressures prior to retrieval to the surface comprising the steps of:
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attaching a flushing device having a chamber containing flushing medium and means to displace the flushing medium therein to a core barrel for disposition downhole, positioning the flushing device and attached core barrel downhole to take a core sample, taking a core sample with the core barrel, and actuating the flushing device following disposition and the taking of a core sample downhole to displace the flushing medium from the chamber and into the core barrel. - View Dependent Claims (15)
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Specification