Method of borehole logging using passive Josephson current detector to directly determine the presence of hydrocarbons
AssigneeChevron Research Company
InventorDon D. Thompson
Life of this patent
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Abstract
A high-gain Josephson-type two-particle tunneling detector is positioned in a borehole penetrating an earth formation and tuned for response in a frequency range of 8400 to 9600 gigahertz. Result: IR emission due to "stretching" vibration of the C-H bonds of adjacently situated hydrocarbons can be detected in surprising fashion.
Claims23
Apparatus for indicating the presence of hydrocarbons in an earth formation traversed by a wellbore by passively detecting infrared radiation therefrom due principally to stretching vibration having frequency components in a range of 8400 to 9600 gigahertz, comprising:
- a tool housing for traversing said wellbore;
- a Josephson-type detector tuned to operate with maximum response in a frequency range of about 8400 to 9600 gigahertz, comprising at least two superconducting bodies positioned within said tool housing defining a current path through a sensing area therebetween;
- means for selectively biasing said Josephson-type detector resulting in a Josephson-type current flow;
- means connected to said Josephson-type detector for monitoring a change in the Josephson zero-voltage current characteristic of said Josephson-type detector due to the incidence of said infrared radiation from said hydrocarbons falling into said sensing area whereby an electrical signal is produced;
- means for indicating said electrical signal as a function of at least depth of said apparatus within said wellbore.
In a tool for logging an earth formation penetrated by a wellbore and including a housing, means for controllably traversing said housing through said wellbore, the improvement comprising:
- (a) a Josephson-type detector means positioned within said housing, tuned to operate in a frequency range of about 8,400 to 9,600 gigahertz and comprising at least two superconducting bodies positioned so as to define a current path through a sensing area therebetween;
- (b) control and monitoring means connected to said Josephson-type detector for tuning said detector to respond to infrared radiation emanating principally from hydrocarbons in a stretching vibratory mode of at least 8400 gigahertz adjacent to said wellbore, and from said radiation response indicating their presence in said formation as a function of depth.
A method of detecting the presence of hydrocarbons in an earth formation traversed by a wellbore which comprises:
- (a) positioning in said wellbore a Josephson-type detector at a known mapping depth, said detector including at least two superconducting bodies defining a current path through a sensing area therebetween, means for biasing said detector to a voltage level to provide Josephson-type zero-voltage current characteristics capable of modification in response to external infrared radiation emanating from said formation hydrocarbons due principally to stretching vibration of C-H bonds thereof in a range of 8400 to 9600 gigahertz.
- (c) monitoring changes in said Josephson-type detector so as to produce an electric signal in accordance with the presence of said infrared radiation emanating from said hydrocarbons in said frequency response range of about 8400 to 9600 gigahertz;
- (c) recording said electrical signal as a function of mapping depth.
In a tool for logging an earth formation penetrated by a well bore and including a housing, and means for controllably traversing said housing through said well bore, the improvement comprising:
- (a) a Josephson-type detector means positioned within said housing, operating at a frequency in the range from about 100 to 10,000 gigahertz and comprising at least two superconducting bodies positioned so as to define a current path through a sensing area therebetween;
- (b) control and monitoring means connected to said Josephson-type detector means for tuning said detector to respond to a selected frequency range of infrared radiation emanating from formation elements adjacent to said well bore in said range of from about 100 to 10,000 gigahertz, and from said radiation response, indicating the presence of hydrocarbonaceous materials in said formation as a function of depth, said control and monitoring means including means for mechanically varying pressure between said superconducting bodies of said Josephson-type detector means at a selected mapping depth within said well bore so as to change the response characteristics of said Josephson-type detector means without necessitating removal of said housing to the earth's surface.
A method of detecting the presence of formation components adjacent to an earth formation traversed by a well bore which comprises:
- (a) positioning in said well bore a Josephson-type detector at a known mapping depth, said detector including at least two superconducting bodies defining a current path through a sensing area therebetween, means for biasing said detector to a voltage level to provide Josephson-type zero voltage current characteristics capable of modification in response to external infrared radiation emanating from said formation components adjacent to said well bore;
- (b) monitoring changes in said Josephson-type zero-voltage current characteristics so to produce an electric signal in accordance with frequency components of incident infrared radiation emanating from said formation in range from about 100 to 10,000 gigahertz;
- (c) recording said electrical signal as a function of mapping depth;
- (d) mechanically varying pressure between said superconducting bodies of said Josephson-type detector at a selected mapping depth within said well bore so as to change the response characteristics of said Josephson-type detector without necessitating removal to the earth's surface.
Dependencies are inferred from the claim text.