Core catcher for use with an hydraulically displaced inner tube in a coring tool

An improvement in a coring tool having a longitudinal axis including a core catcher, said improvement comprising:

• an upper section of said core catcher;
• and
• a lower section of said core catcher connected to and extending from said upper section, said lower section including means for collapsing said lower section inwardly toward said longitudinal axis of said coring tool as said core catcher is longitudinally displaced within said coring tool,
• wherein said means for collapsing comprises:
• a plurality of longitudinal ribs interconnected by thin integral longitudinally extending wall portions, said ribs and wall portions forming said lower section of said core catcher, said ribs having a tapering thickness beginning with a maximal thickness at a first longitudinal point and decreasing in radial thickness to a lowermost edge of said lower section of said core catcher;
• and
• an opposing adjacent tapering internal surface of said coring tool, said plurality of ribs being in contact with said adjacent internal surface and mating therewith, the surface of contact between said ribs and said adjacent internal surface of said coring tool defining a frustoconical shape with a decreasing diameter to said lowermost edge of said lower section of said core catcher
• whereby a substantially uniform compressive force is exerted by said core catcher against a core disposed within said coring tool.

An improvement in a coring tool having a longitudinal axis including a core catcher, said improvement comprising:

• an upper section of said core catcher;
• and
• a lower section of said core catcher connected to and extending from said upper section, said lower section including means for collapsing said lower section inwardly toward said longitudinal axis of said coring tool as said core catcher is longitudinally displaced within said coring tool,
• wherein said means for collapsing comprises a thin walled corrugated surface forming said lower section of said core catcher, said corrugations being comprised of a plurality of radially extending fingers, the radial extent of said fingers running from a maximal at a first longitudinal point on said core catcher to a minimal at a lowermost edge of said lower section of said core catcher, and an internal mating and opposing surface of said coring tool, said corrugations forming a surface of contact with said inner surface of said coring tool and defining a frustoconical shape with a decreasing diameter toward said lowermost edge of said lower section of said core catcher
• whereby a substantially uniform compressive force is exerted by said core catcher against a core disposed within said coring tool.

A core catcher for use in a coring tool, said coring tool having an internal frustoconical shaped surface comprising:

• an upper cylindrical section longitudinally slideable within said coring tool;
• and
• a collapsible lower section integral with said upper section for grasping and providing a substantially uniform circumferential compressive force on said core, said lower section in slideable contact with said internal surface of said coring tool;
• wherein said collapsible lower section is comprised of a plurality of resilient segments and is therefore reusable;
• wherein said resilient segments comprises a plurality of longitudinally disposed tines, said tines, defined by corresponding plurality of thin slots defined through said lowre section of said core catcher;
• wherein said thin slots are slanted and nonradially disposed through said lower section of said core catcher.

A core catcher for use in a coring tool, said coring tool having an internal frustoconical shaped surface comprising:

• an upper cylindrical section longitudinally slideable within said coring tool;
• and
• a collapsible lower section integral with said upper section for grasping and providing a substantially uniform circumferential compressive force on said core, said lower section in slideable contact with said internal surface of said coring tool;
• wherein said collapsible lower section is comprised of a permanently deformable wall and is therefore nonreusable.

A core catcher for use in a coring tool, said coring tool having an internal frustoconical shaped surface comprising:

• an upper cylindrical section longitudinally slideable within said coring tool;
• and
• a collapsible lower section integral with said upper section for grasping and providing a substantially uniform circumferential compressive force on said core, said lower section in slideable contact with said internal surface of said coring tool;
• wherein said collapsible lower section is comprised of a permanently deformable wall and is therefore nonreusable;
• wherein said permanently deformable wall is comprised of a plurality of longitudinally extending ribs interconnected by a thin web.

A core catcher for use in a coring tool, said coring tool having an internal frustoconical shaped surface comprising:

• an upper cylindrical section longitudinally slideable within said coring tool;
• and
• a collapsible lower section integral with said upper section for grasping and providing a substantially uniform circumferential compressive force on said core, said lower section in slideable contact with said internal surface of said coring tool;
• wherein said collapsible lower section is comprised of a permanently deformable wall and is therefore nonreusable;
• wherein said permanently deformable wall is comprised of a corrugated web.

A method for retaining a core within a coring tool comprising the steps of:

• cutting said core;
• disposing said cut core within said coring tool;
• longitudinally displacing a core catcher within said coring tool without dependence upon gravity and without dependence upon interference fit between said core and core catcher;
• and
• permanently structurally collapsing said core catcher by said longitudinal displacement of said core catcher within said coring tool to exert a radially compressive force against said core.

A method for retaining a core within a coring tool comprising the steps of:

• cutting said core;
• disposing said cut core within an inner tube within said coring tool;
• displacing said inner tube within said coring tool;
• and
• permanently structurally collapsing at least a terminal portion of said inner tube by said longitudinal displacement of said inner tube within said coring tool to exert a radially compressive force against said core.