Method and apparatus for coring with an in situ core barrel sponge

Abstract

Jamming caused by absorbent members in sponge core barrels or loss of coring information caused by oil wipes in oil field boreholes in which sponge core coring tools are disposed can be avoided by employing a method and tool wherein the absorbent member is formed in placed in contact about the core after the has been cut and disposed within the inner tube. In the illustrated embodiment, a liquid foam is catalytically formed from two constituent parts. The constituent parts are hydraulically forced from longitudinal chambers defined within the inner tube walls into an area in the throat of the bit where the parts meet and exothermically generate a liquid foam. The liquid foam rises into a plurality of longitudinal open chambers defined within the inner tube. Each of the open chambers has a longitudinal slot defined therethrough which communicates the chamber with the axial bore in which the core is disposed. The liquid foam flows into the longitudinal chambers and into the annular space between the inside surface of the inner tube and the core. Ultimately, the core is totally immersed in the liquid foam. Thereafter, within a predetermined curing time, the liquid foam cures to form a sponge-like solid. The oil bearing core may not be retrieved to the well surface. As the core is depressurized during retrieval, oil forced from the core by escaping water and gas is retained within the sponge for later analysis.