High pressure coring assembly and method

摘要

A wireline or drill pipe retrievable coring tool with an inner barrel to receive a core, a bottom coring tool valve operable to seal off a bottom of the inner barrel and at least one pressure canister operable to receive fluid from the core in the inner barrel. The pressure canister is operable to significantly reduce the pressure inside the inner barrel utilizing an expandable chamber to receive fluid from the core as the tool is removed from the wellbore. In one embodiment, a bottom valve mechanism moves the cored formation materials out of the way of the bottom valve before the bottom valve is closed.

主权项

1. A coring tool retrievable to a surface position from a wellbore to obtain a cored formation from said wellbore, said coring tool being receivable within an outer barrel, a coring bit being interconnected with said outer barrel, comprising:
an inner barrel operable to receive said cored formation within a core receiving region of said inner barrel; a bottom valve operable to seal off an end of said inner barrel; and at least one canister receivable within said outer barrel, said at least one canister comprising an expandable chamber connected to receive and store a fluid flow out of said cored formation in said inner barrel when said inner barrel and said at least one canister are retrieved from said well, said at least one canister being axially spaced from said core receiving region of said inner barrel and being on an opposite side of said inner barrel from said coring bit; a fluid flow path between said core receiving region and said at least one canister through which said fluid flow out of said cored formation passes into said at least one canister; and a relief valve mounted in said fluid flow path between said canister and said core receiving region constructed to be operable to open and close, said relief valve being operable to initially obstruct said fluid flow from said core receiving region to said at least one canister and subsequently allow said fluid flow in order to limit pressure in said core receiving region.