Method and apparatus for obtaining a core sample at ambient pressure

Claim 1

Apparatus for capturing a core sample cut from a formation of interest, comprising: (a) demountable chamber means having: (1) a surrounding housing; (2) a central, top located, core receiving opening; (3) a valve element with a core sized passage therethrough for receiving a core into said housing; (4) means for operating said valve element to open and close; and (5) an internal core receiving cavity formed by a surrounding resilient sleeve; (b) a fluid chamber surrounding said sleeve; (c) fluid pressure transfer means extending from the exterior of said chamber means to said fluid chamber; (d) first and second valve controlled fluid passage into said fluid chamber and internal cavity; (e) means for mounting said chamber means on a laboratory test instrument; and (f) means enabling a laboratory test instrument piston to extend into said chamber means to load the core in said cavity.

Claim 3

A method of obtaining a core sample from a well borehole and placing the core sample in a removable core sample chamber including an internal core sample cavity and a fluid isolating wall defining said cavity around the core sample and the method comprises the steps of: (a) positioning the removable chamber in a sonde; (b) lowering in the borehole the sonde supporting a core cutter to enable cutting a core sample from a formation of interest; (c) controllably transferring the core sample by insertion of the core sample into the open removable chamber to receive the core sample and connate formation fluids; (d) isolating fluid in the chamber to equal the ambient pressure at the formation of interest after insertion of the core sample into the removable chamber; (e) sealing the cavity after core insertion; (f) opening a valve means to regulate fluid pressure on the wall to ambient pressure; (g) closing the core sample receiving removable chamber to capture the core sample; (h) measuring ambient conditions at the formation of interest; (i) retrieving the sonde from the well; and (j) removing the chamber with the core sample therein at the isolated pressure.

Claim 4

A method of obtaining a core sample from a well borehole and placing the core sample in a removable core sample chamber including an internal core sample cavity and a fluid isolating wall defining said cavity around the core sample and the method comprises the steps of: (a) positioning the removable chamber in a sonde; (b) lowering in the borehole the sonde supporting a core cutter to enable cutting a core sample from a formation of interest; (c) controllably transferring the core sample by insertion of the core sample into the open removable chamber to receive the core sample and connate formation fluids; (d) isolating fluid in the chamber to equal the ambient pressure at the formation of interest after insertion of the core sample into the removable chamber; (e) sealing the cavity after core insertion; (f) opening a valve means to regulate fluid pressure on the wall to ambient pressure; (g) closing the core sample receiving removable chamber to capture the core sample; (h) measuring ambient conditions at the formation of interest; (i) retrieving the sonde from the well; and (j) removing the chamber with the core sample therein at the isolated pressure.

Claim 21

A method of obtaining a core sample in a core sample receiving chamber from a well borehole comprising the steps of: (a) initially filling the core sample receiving chamber with an incompressible fluid; (b) initially opening a valve element aligned with the chamber to enable core sample insertion therethrough; (c) covering the chamber with a sacrificial cover; (d) continually changing the pressure in the chamber as the sonde is lowered into a well borehole. (e) positioning a removable chamber in a sonde; (f) lowering in the borehole the sonde supporting a core cutter to enable cutting a core sample from a formation of interest; (g) controllably transferring the core sample by insertion of the core sample into said removable chamber; (h) isolating pressure in the chamber equal to the ambient pressure at the formation of interest after insertion of the core sample into the removable chamber; (i) retrieving the sonde from the well; and (j) removing the chamber with the core sample therein at the isolated pressure.

Claim 22

A method of obtaining a core sample in a core sample receiving chamber from a well borehole comprising the steps of: (a) initially filling the core sample receiving chamber with an incompressible fluid; (b) initially opening a valve element aligned with the chamber to enable core sample insertion therethrough; (c) covering the chamber with a sacrificial cover; (d) continually changing the pressure in the chamber as the sonde is lowered into a well borehole. (e) positioning a removable chamber in a sonde; (f) lowering in the borehole the sonde supporting a core cutter to enable cutting a core sample from a formation of interest; (g) controllably transferring the core sample by insertion of the core sample into said removable chamber; (h) isolating pressure in the chamber equal to the ambient pressure at the formation of interest after insertion of the core sample into the removable chamber; (i) retrieving the sonde from the well; and (j) removing the chamber with the core sample therein at the isolated pressure.