Method and apparatus for detecting the thermal characteristics of a subsurface formation in situ

An apparatus for detecting the thermal characteristics of a subsurface formation in situ wherein a borehole has been drilled into the formation comprising means disposed in the borehole remote from the surface for conducting test energy subject to change by subjection to low temperature through said formation to the surface, means positioned in the borehole between said conducting means and the surface for withdrawing the ambient heat from the formation to form a zone of cooling in a position through and about which said test energy passes, and means mounted on the surface for detecting changes in the test energy incident to the passage thereof through said zone to permit determination of the size of the zone thereby to determine the characteristics of thermal conductivity of said formation.

An apparatus for detecting the thermal characteristics of a subsurface formation in situ wherein a borehole has been drilled into the formation comprising means disposed in the borehole remote from the surface for conducting test energy subject to change by subjection to low temperature through said formation to the surface;

• means positioned in the borehole between said conducting means and the surface for withdrawing the ambient heat from the formation to form a zone of cooling in a position through and about which said test energy passes, and wherein the heat withdrawing means includes a vessel of cryogenic material adapted to be selectively positioned in the borehole and said heat withdrawing means further includes a seat member of heat conductive material positioned in the borehole in a predetermined location and adapted to receive said vessel and to conduct the ambient heat of the formation to the cryogenic material borne thereby to form a zone of cooling in the formation about the seat member;
• and means mounted on the surface for detecting changes in the test energy incident to the passage thereof through said zone to permit determination of the size of the zone thereby to determine the characteristics of thermal conductivity of said formation.

A method for detecting the thermal characteristics of a subsurface formation in situ comprising inserting cryogenic material into said formation to a predetermined position to produce a zone of cooling thereabout;

• conducting a plurality of paths of test energy, subject to detectable alteration by passage through a cooled medium, from a predetermined position spaced from the zone of cooling through and laterally of said zone of cooling;
• individually detecting the energy in said paths subsequent to passage through and laterally of said zone;
• and recording the energy altered by passage through the zone in comparison with that not altered to determine the thermal conductivity of the formation as indicated by the size of said zone determined from the recorded energy and the known distance between the position of energy discharge and the position of the cryogenic material.

A method for detecting the thermal characteristics of a subsurface formation in situ comprising inserting cryogenic material into said formation to a fixed position to produce a zone of cooling in the formation thereabout;

• emitting test energy subject to detectable reduction by passage through the zone of cooling from a position spaced from the zone of cooling;
• individually detecting the energy conducted along a plurality of paths of predetermined relation from said position, some of which extend through the zone and others of which extend past the zone in laterally spaced relation thereto;
• and comparing the energy conducted through the zone with the energy conducted passed the zone to determine the thermal conductivity of the formation as indicated by the size of said zone.

An apparatus for detecting the thermal characteristics of a subsurface formation in situ wherein a borehole has been drilled into the formation comprising means positioned in the borehole remote from the surface for conducting test energy, subject to change by passage through a cooled medium, through said formation to the surface;

• a vessel adapted to receive cryogenic material;
• means mounted in the borehole between said conducting means and the surface for receiving said vessel and establishing heat withdrawing communication between cryogenic material received in said vessel and the formation about said position to form a zone of cooling through and about which said test energy passes;
• and means mounted on the surface for detecting changes in the test energy incident to the passage thereof through said zone to permit determination of the size of the zone thereby to determine the characteristics of thermal conductivity of said formation.