Self activating, positively driven concealed core catcher

An improvement in a full closure catcher disposed within a coring tool, said tool having a longitudinally displaceable inner barrel, said tool for cutting the core comprising:

• a plurality of closable valves disposed outside of said inner barrel and displaceable within said inner barrel space to fully close said inner barrel;
• and
• compression spring-loaded cam means for selectively positively displacing each of said plurality of valves into said inner barrel space, when said inner barrel is longitudinally displaced to unconceal said cam means,
• wherein each of said plurality of valves is rotatably coupled to a clam shell housing, said clam shell housing circumferentially disposed outside of and concentric with said inner tube, the longitudinal position of said clam shell housing being at least limited with respect to said outer tube, said plurality of flapper valves being selectively concealed by said inner tube, said flapper valves being circumferentially disposed outside of said inner tube and capable of collectively forming a full closure of said inner barrel;
• wherein said compression spring means for positively displacing each of said valves comprises a cam ring circumferentially disposed about said inner tube and concentric therewith, and a coil compression spring circumferentially disposed outside of said inner tube and concentric therewith, said compression spring being disposed in said clam shell housing and preloaded to bear against said cam ring, said cam ring in turn bearing against each of said plurality of valves to urge said valves into full closure,
• whereby full closure of said inner barrel is provided without dependency upon relative descent of said core within said inner barrel.

A full closure core catcher for use within a coring tool having an inner tube and longitudinal axis comprising:

• a terminal extension of said inner tube extending along said longitudinal axis of said coring tool;
• closure means adjacent said terminal extension for providing full closure of said inner tube, said closure means capable of assuming an open and a closed configuration, said closure means circumferentially disposed radially outside of said terminal extension of said inner tube when said closure means is in said open configuration, said inner tube concealing said closure means and retaining said first means in said open configuration;
• and
• cam means for providing a substantially longitudinally directed force against said closure means to urge said closure means from said open configuration to said closed configuration, said closure means assuming said closed configuration when said terminal extension of said inner tube is longitudinally displaced with respect to said closure by a predetermined distance,
• wherein said closure means comprises a plurality of clam shell flapper valves;
• wherein said cam means comprises a cam ring and a preloaded compression spring, said cam ring and compression spring circumferentially and concentrically disposed about said terminal extension of said inner tube, said cam ring slidingly contacting said plurality of flapper valves to urge said flapper valves into said closed configuration when said flapper valves are free to rotate by relative longitudinal displacement of said terminal extension of said inner tube with respect to said flapper valves by said predetermined distance,
• whereby a full closure core catcher is provided which is positively actuated when said inner tube is relatively displaced within said coring tool to uncover said concealed closure means.

A full closure core catcher for use within a coring tool having a longitudinal axis comprising:

• a terminal extension of said inner tube extending along said longitudinal axis of said coring tool;
• closure means adjacent said terminal extension for providing full closure of said inner tube, said closure means capable of assuming an open and a closed configuration, said closure means circumferentially disposed radially outside of said terminal extension of said inner tube when said closure means is in said open configuration, said inner tube concealing said closure means and retaining said first means in said open configuration;
• and
• cam means for providing a substantially longitudinally directed force against said closure means to urge said closure means from said open configuration to said closed configuration, said closure means assuming said closed configuration when said terminal extension of said inner tube is longitudinally displaced with respect to said closure by a predetermined distance,
• wherein said closure means comprises a plurality of clam shell flapper valves;
• wherein said cam means comprises a cam ring and a compression spring, said cam ring and compression spring circumferentially and concentrically disposed about said terminal extension of said inner tube, said cam ring slidingly contacting said plurality of flapper valves to urge said flapper valves into said closed configuration when said flapper valves are free to rotate by relative longitudinal displacement of said terminal extension of said inner tube with respect to said flapper valves by said predetermined distance;
• and
• further comprising a split core spring circumferentially disposed outside of said terminal extension of said inner tube, and an inner tube shoe circumferentially disposed outside of and concentric with said terminal extension of said inner tube and split core spring, said inner tube shoe and split core spring having mutually contacting surfaces arranged and configured into a frustoconical shape to compress said split core spring radially inward as said split core spring is longitudinally downwardly displaced along said frustoconical surface of said inner tube shoe,
• whereby a full closure core catcher is provided which is positively actuated when said inner tube is relatively displaced within said coring tool to uncover said concealed closure means.

A full closure core catcher for use within a coring tool having a longitudinal axis comprising:

• a terminal extension of said inner tube extending along said longitudinal axis of said coring tool;
• closure means adjacent said terminal extension for providing full closure of said inner tube, said closure means capable of assuming an open and a closed configuration, said closure means circumferentially disposed radially outside of said terminal extension of said inner tube when said closure means is in said open configuration, said inner tube concealing said closure means and retaining said first means in said open configuration;
• and
• cam means for providing a substantially longitudinally directed force against said closure means to urge said closure means from said open configuration to said closed configuration, said closure means assuming said closed configuration when said terminal extension of said inner tube is longitudinally displaced with respect to said closure by a predetermined distance,
• wherein said closure means comprises a plurality of clam shell flapper valves;
• wherein said cam means comprises a cam ring and a compression spring, said cam ring and compression spring circumferentially and concentrically disposed about said terminal extension of said inner tube, said cam ring slidingly contacting said plurality of flapper valves to urge said flapper valves into said closed configuration when said flapper valves are free to rotate by relative longitudinal displacement of said terminal extension of said inner tube with respect to said flapper valves by said predetermined distance;
• and
• further comprising a clam shell housing circumferentially disposed outside of and concentric with said terminal extension of said inner tube and radially disposed outside of said plurality of flapper valves, each flapper valve being pivotably coupled to said clam shell housing, said clam shell housing defining a circumferential annular space into which said plurality of flapper valves are disposed when in said open configuration, said compression spring and cam ring similarly disposed within said annular space defined in said clam shell housing, said compression spring being preloaded when said plurality of flapper valves are in said open configuration, one end of said compression spring bearing against said clam shell housing and the opposing end of said compression spring bearing against said cam ring to longitudinally force said cam ring downwardly against said plurality of flapper valves to urge each flapper valve from said open to said closed configuration whenever rotation of said flapper valve about said pivotal coupling with said clam shell housing is possible,
• whereby a full closure core catcher is provided which is positively actuated when said inner tube is relatively displaced within said coring tool to uncover said concealed closure means.

An improvement in a full closure catcher in a coring tool having an inner tube, said full closure catcher configurable in an open configuration and closed configuration, said improvement comprising:

• cam means circumferentially disposed outside of said inner tube and concentric therewith, said cam means longitudinally displaceable in said coring tool, said cam means in sliding contact with said full closure core catcher operative to configure said full closure core catcher from said open configuration into said closed configuration;
• and
• coil compression spring means circumferentially disposed outside of said inner tube and concentric therewith, said compression spring means generating a longitudinal force within said coring tool, said longitudinal force being applied to said cam means to longitudinally urge said cam means against said full closure core catcher;
• wherein said cam means is a freely floating cam ring telescopically disposed outside of said inner tube and concealed by said inner tube, said full closure core catcher similarly being concealed by said inner tube when in said open configuration;
• wherein said full closure catcher comprises a plurality of flapper valves, each flapper valve having a rear inclined surface, said cam ring arranged and configured to slidingly contact said rear surface of each said flapper valve, whereby longitudinal displacement of said cam ring with respect to said flapper valve rotates each of said flapper valves into said coring tool.

An improvement in a method for retaining a core within a coring tool comprising the steps of:

• concealing each core catcher disposed within said coring tool from said core as said core is being cut and disposed into said coring tool;
• uncovering each core catcher disposed within said coring tool to permit activation of at least one core catcher;
• and
• activating at least one core catcher into at least a partially closed configuration by permitting longitudinal expansion of a preloaded compression spring within said coring tool, said step of activating said core catcher being triggered by said step of uncovering said corresponding core catcher,
• whereby said at least one core catcher is reliably activated within said coring tool without dependence upon gravity or diametrical interference fit with said core, and whereby said core is disposed within said coring tool without obstruction or disturbance within said coring tool without obstruction or disturbance by any core catcher;
• where said step of activating said at least one core catcher comprises the step of driving a cam ring longitudinally within said coring tool against a plurality of flapper valves, said cam ring being disposed circumferentially outside said plurality of flapper valves, a surface contact between said cam ring and flapper valves forming a frustoconical shape whereby said longitudinal movement of said cam ring rotates each one of said plurality of flapper valves into said tool into a closed configuration.

A method for cutting and disposing a core within a coring tool without substantial disturbance of said core comprising the steps of:

• cutting said core;
• disposing said cut core within a smooth inner tube;
• longitudinally displacing said inner tube within said coring tool to expose a core catcher;
• and
• activating said core catcher to retain said core within said coring tool, wherein said step of activating said core catcher is by expanding a preloaded compression spring to drive a cam means longitudinally downward within said coring tool, said cam means forcing said core catcher radially inward into the inner barrel of said coring tool,
• where said step of activating said core catcher is comprised of the step of fully uncovering said core catcher to permit said core catcher to assume a preferred fully closed configuration, said fully closed configuration being a biased configuration of said core catcher;
• where said step of activating said core catcher is further comprised of the step of fully uncovering a split spring core catcher to permit said split spring to assume a preferred configuration of diametrical interference contact between said split spring core catcher and said core, said split spring core catcher and full closure core catcher being concealed prior to activation,
• whereby a core is cut and disposed within a coring tool without substantial disturbance of said core and said core catcher is activated without dependence upon gravity or diametrical interference fit with said core.