Wells – Processes – With indicating – testing – measuring or locating
Reexamination Certificate
1999-08-20
2001-11-27
Neuder, William (Department: 3672)
Wells
Processes
With indicating, testing, measuring or locating
C260S66500B
Reexamination Certificate
active
06321839
ABSTRACT:
FIELD OF THE INVENTION
Our present invention relates to a method of subsurface exploration in which a probe is introduced into a borehole or well and, at a measuring region below the surface of the ground, the concentration of at least one material is measured. The invention also relates to a probe for carrying out the method, i.e. for detecting the concentration of at least one substance at a region below the surface of the ground and utilizing the coupling of electromagnetic radiation or energy to the measurement region and/or the coupling of electromagnetic energy out of the measurement region.
BACKGROUND OF THE INVENTION
The coupling of electromagnetic energy into and out of a subsurface region in which the concentration of a substance is to be measured, is described in principle in the commonly owned copending application Ser. No. 09/333,349 filed Jun. 15, 1999 and based upon German Application 19826265, which is hereby incorporated in its entirety by reference.
The substance which can have its concentration measured by this method can be a substance already in the ground, namely, a natural substance, or it can be a substance artificially present at the measurement location, e.g. because it is intentionally introduced like a marker substance or tracer substance, or because it is a contaminant which, for example, can leach from a waste disposal site or dump.
A method of subsurface exploration in which a marker substance is introduced at at least one location in the ground and in which the migration of that substance is measured has been described in the publication “Development of a Single Borehole Process for the Measurement of Horizontal Ground Water Flow” (translated title) by M. Schöttler. In this article, a probe which can be introduced into a borehole or well for carrying out the process is described. The probe can comprise a measurement cell which contains two light sources, a lens system and a special video camera. The marker substance can be a fluorescent material which is introduced centrally over an observation range of several millimeters in size and on which the camera is focused. This region lies axially centrally of the measurement range at a location in which the ground water flow passes freely.
The light sources emit light and the marker substance re-emits light shifted in wavelength from the original emitted light and registered by the video camera as illuminated image points. The result is a high contrast point image which is picked up by video techniques and enables the flow direction of the marker substance to be ascertained.
In another probe for insertion into a borehole or well, marketed by GSF Munich, Germany, the movement of a radioactive marker substance can be detected. This system, however, requires the use of short-lived isotopes which must be prepared by irradiation in a nuclear reactor. The process is relatively expensive and, since the marker substances have short lives, the marker substances can be stored only for limited periods of time. As a consequence, carrying out this latter process is problematical.
A probe for lowering into a well for subsurface exploration has also been developed by the University of California and enables sampling of the ground water to be effected, the sample volumes being pumped to the surface. This system does not permit in-situ measurements of concentration or the like.
Finally, mention can be made of a probe developed by the Technical University of Freiberg, Germany which operates utilizing heat pulses. This system can only be used to detect high ground water velocity.
OBJECTS OF THE INVENTION
It is, therefore, the principal object of the present invention to provide an improved method of subsurface exploration which can be carried out in a simple and economical manner and enables the flow direction of a substance and its concentration to be detected without the drawbacks of some of the methods previously described.
It is a further object of this invention to extend the principles set forth in the copending application mentioned above to improve the versatility thereof.
It is also an object of the invention to provide an improved probe, which can be lowered into a well or borehole and which can provide in a cost effective and simple manner, an indication of the concentration of a substance in a measurement reaching below the ground, details with respect to flow direction and the like.
SUMMARY OF THE INVENTION
These objects and others which will become apparent hereinafter are attained, in accordance with the invention, in a method whereby electromagnetic radiation is coupled into the measurement region at various locations and/or electromagnetic energy is coupled out of the measurement region at various locations and from the electromagnetic energy carried out of the region, a measurement can be made as to a substance at this region.
More particularly, a subsurface exploration method according to the invention can comprise the steps of
(a) introducing a probe into a borehole in the ground to a subsurface region to be investigated;
(b) coupling electromagnetic energy into the region to induce emission of electromagnetic radiation from at least one substance in the region;
(c) coupling electromagnetic energy of the electromagnetic radiation emitted by the substance out of the region, at least one of the steps of coupling electromagnetic energy into the region and of coupling electromagnetic energy out of the region being effected at a plurality of locations in the region; and
(d) determining a concentration of the substance from the electromagnetic energy coupled out of the region.
The apparatus for subsurface exploration according to the invention can comprise:
a probe adapted to be introduced into a borehole in the ground to a subsurface region to be investigated;
means in the probe a probe adapted to be introduced into a borehole in the ground to a subsurface region to be investigated;
means for coupling electromagnetic energy into the region to induce emission of electromagnetic radiation from at least one substance in the region;
means for coupling electromagnetic energy of the electromagnetic radiation emitted by the substance out of the region, at least one of the means for coupling electromagnetic energy into the region and out of the region being effective at a plurality of locations in the region; and
means connected to the means for coupling electromagnetic energy out of the region for determining a concentration of the substance from the electromagnetic energy coupled out of the region.
Advantageously, the electromagnetic radiation includes light rays or a light beam and at least one optical fiber is provided for coupling the light energy into the region and/or for coupling the light energy out of the region. When an optical fiber is provided as the optical waveguide for the light energy, the optical fiber is mounted so that it can be moved, preferably by an electric motor.
It is advantageous, in accordance with the invention, that the electromagnetic radiation be deflected so that, by movement of the deflector, the electromagnetic energy can be brought to or picked up from various locations within the measurement region. The deflection of the electromagnetic energy can be via any type of deflector suitable for the particular electromagnetic energy used. It can, for example, include a mirror or prism or the like or can simply be a bent waveguide such as a bent optical fiber.
Advantageously, the electromagnetic energy is deflected along a predetermined path which can, for example, be a circular path. Advantageously, the electromagnetic energy can be deflected by a rotating deflection means such as a prism, a lens or a mirror.
According to a feature of the invention, the light ray or beam can have an emission wavelength between 200 nm and 950 nm.
It is advantageous further to so carry out the method of the invention that the substance is excited by the light radiation. In this case, the substance can be a luminous substance which is excited to luminescence by absorption of light energy. The emission
Hashagen Uwe
Höltenmeier Jürgen
Vereecken Harry
Dubno Herbert
Forschungszentrum Julich GmbH
Neuder William
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