Method and apparatus for examining earth formations

A method and apparatus are described for logging an open hole well, or the like, for the purpose of determining the presence of a given constituent in the various substrata and for providing means and method for determining the degree of presence of the constituent in a given formation where it has been located. A probe capable of being lowered into a bore hole includes a color video camera, a particular form of light source, apparatus for carrying and issuing a spray of cleaning substance and apparatus for carrying and issuing a chemical which facilitates the analysis of the degree of presence of the constituent. The probe is lowered to the bottom of the bore hole and then raised to a desired level. A cleaning jet sprays the surface to be inspected. The cleaned surface is then illustrated with light having a frequency in a predetermined frequency range and the reflected light is directed to the camera. The video signal is conducted to the surface where it is displayed. Examination of the color content of the video display allows for determination of the presence or absence of the constituent in question. Should it be determined that this constituent is present the formation undergoing examination is sprayed with a colorant which, when illuminated, provides a reflected light, the intensity of the color produced by the reflected light is in correspondence with the degree of presence of the constituent in the formation being examined.

BACKGROUND OF THE INVENTION 
This invention relates to well logging and, more particularly, to the means 
and method for providing a direct visual indication of the presence of a 
predetermined constituent of an earth formation. 
Various techniques and apparatus are now used for the purpose of well 
logging to study the properties of subsurface formations to determine the 
presence or absence of given naturally occurring substances, such as oil. 
The principal techniques presently being used either involve the taking of 
a core sample from the bore hole and subsequently chemically analyzing it, 
or measuring the radioactive properties of the subsurface formations. In 
either case the measurement techniques are complex, and the means by which 
results are actually determined are similarly complex. Moreover, the 
results of any such measurement are not produced immediately, and a 
relatively long period of time is required before a determination can be 
made regarding the content of the subsurface formations being examined. 
Using core sample techniques it is necessary to physically remove a portion 
of the subsurface formation being examined to what is substantially a 
laboratory environment to permit a chemical analysis. There the core 
sample is chemically analyzed to determine its constituents and, 
particularly, to determine the degree of presence of the substance being 
sought, such as oil. Obviously, this technique is cumbersome, and 
presently available methods of chemical analysis of such core samples 
require significant periods of time before completion. In many 
circumstances, particularly in an oil drilling environment, such losses of 
time are economically disadvantageous. 
The other major technique for well logging involves the use of means for 
studying the radioactive properties of the subsurface formations in 
question. This technique could involve the measurement of natural 
radioactive properties, or it could involve measurements wherein the 
radioactivity is artificially induced. The means by which this 
radioactivity is measured are complex, expensive and often unreliable in 
the harsh environment in which they must be used. For example, in the case 
where gamma radiation is being measured, crystals must be used which 
respond to the gamma radiation to thereby produce light energy which is 
subsequently converted to electrical energy having a complex wave form. It 
is then necessary to rigorously analyze the wave form content of the 
aforementioned electrical signal, and this analysis often requires the aid 
of a computer. It is only after this complex mathematical analysis of the 
electrical wave form generated as described above is completed can there 
be made a determination as to the presence or absence of the substance 
being sought in the earth formation being analyzed. Obviously, this 
technique requires complex and expensive apparatus and requires complex 
and time-consuming analysis procedures before a conclusion can be reached. 
It is, therefore, an object of this invention to provide a means and method 
for examination of earth formations in, for example, a bore hole which 
will provide a direct and immediate indication of the presence or absence 
of a given substance in the formation. 
It is another object of this invention to provide a means and method for 
the in situ examination of earth formations penetrated by a bore hole 
which utilizes relatively simple and inexpensive apparatus and requires no 
subsequent chemical or mathematical analysis. 
An additional object of this invention is to provide a means and method for 
the examination of earth formations in a bore hole which are relatively 
simple to operate and which do not require the presence of highly skilled 
personnel to carry out the method nor to receive and understand the 
results. 
SUMMARY OF THE INVENTION 
The aforementioned and other objects are obtained in accordance with the 
principles of the invention through the use of a means and method for 
examining earth formations to determine the presence of a substance 
therein which includes illuminating the earth formation of interest with 
light of a given frequency. If it is petroleum hydrocarbons which are to 
be located, the earth formation is illuminated with light in the 
ultraviolet frequency range. The light reflected from the formation, so 
illuminated, is viewed for its color content. On the basis of the color 
content of this reflected light the presence or absence of the constituent 
of the earth formation of interest can be determined. 
If it is desired to determine the degree of presence of the constituent in 
question, such as the ratio of oil to water in the formation being 
examined, the following additional technique is used. A colorant is used 
which will not dilute in water, and which has the capability of adhering 
to molecules of the substance, the presence of which in the earth 
formation is being analyzed. The amount of colorant which will remain and 
not be dissipated is in direct proportion to the number of molecules of 
the substance in question present. Thus, the greater the number of 
molecules of the substance, the more intense the presence of the colorant. 
This colorant then may be examined for its intensity by visual means, and 
this will bear a direct relation to the degree of presence of the 
substance in question.

DETAILED DESCRIPTION OF THE DRAWINGS 
In FIG. 1 is illustrated an assembly including the preferred embodiment of 
the invention. As is apparent, the means for carrying out the measurements 
in accordance with the invention may readily be carried in a van-type 
vehicle 10. Van 10 carries a winch mechanism 12 for operating cable 13 to 
support and raise and lower probe assembly 14. Cable 13 also carries in a 
coaxial fashion wires for connecting the probe assembly to a console 16 in 
van 10. A television signal communicated from probe 14 via cable 13 
appears on video display 17 of console 16. A video tape recorder (not 
shown) may be provided for making a permanent record of the video display. 
At 18 is illustrated a casing for the bore hole within which probe 14 is 
to be lowered for examination of the earth formations therein. 
As illustrated in FIG. 2, probe 14 is connected to cable 13 by means of a 
control cable head 20. The probe is divided in this embodiment into three 
sections. The first of these sections 22 is mechanically connected to 
cable head 20 and carries a chemical tank assembly the uses for which will 
become more apparent from the description hereinbelow. Section 22 of probe 
14 is connected at screw joint 23 to a section 24 which carries mechanical 
components, such as pumps for delivering the chemicals from section 22 in 
the manner to be described below. 
A third section 26 is coupled to section 24 by means of cliplocks 25. A 
bottom bumper 28 is connected to the other end of probe section 26. This 
bottom bumper is of a material which will allow the probe to make physical 
contact with the bottom of a bore hole or the like and prevent the 
possibility of damage. 
The means by which the visual examination of an earth formation is carried 
out, as well as the means for spraying an appropriate cleaning substance 
and colorant are contained in section 26 of the probe. In a manner to be 
more fully described hereinbelow the earth formation to be observed is 
isolated through extension of a bellows mechanism 30 to the sides of the 
hole in the manner to be more fully described below. This bellows 
mechanism is carried in an outwardly tapered portion 31 of probe section 
26, and surrounds openings 33a and 33b in portion 31 of the probe. 
Arcuate members 32 are provided at various points around the periphery of 
the probe assembly in order to provide for centering of it within the bore 
hole and to prevent inadvertent contact with the sides of the bore hole 
and, perhaps, resulting damage. 
FIG. 3 illustrates in cross-sectional view the working components of probe 
assembly 14 which are found in sections 24 and 26 thereof. 
The probe assembly contains a coaxially constructed color video camera 34 
which receives its visual images from lens 36a and 36b via right angle 
optical coupling 38. The lens 36a and 36b are mounted to receive light 
through openings 33a and 33b, respectively. Camera 34 is constructed in 
the conventional manner to provide the appropriate electronic signals 
resulting from the sensed light. These camera components and their 
operation, being conventional, will not be described further herein, but 
they are identified by appropriate legends in FIG. 3. In the preferred 
embodiment this camera is a Model 3800 color video camera manufactured by 
California Video Corporation. The electronic output from camera 34 appears 
at cable coupling 40 for communication through coaxial cable 13 to console 
16 and video display 17. 
For purposes of initial visual examination of the earth formation in 
question and for use in connection with this preferred embodiment for the 
determination of the presence of petroleum hydrocarbons, a pair of 
ultraviolet lights 42a and 42b are provided. These are, as well, mounted 
to emit light through openings 33a and 33b. The illustrated wire harness 
41 carries wires 43 which connect with a power source for operating these 
lights. In addition, a pair of quartz lamps 44a and 44b are in this 
embodiment mounted below lens assembly 38 for purposes to be described, 
and wires 45 also carried in wire harness 42 provide the power for 
actuation and operation of these lights. 
As briefly discussed hereinabove, bellows 30 is expanded during an 
examination operation to isolate the earth formation being examined. The 
bellows receives air under pressure through couplings 48a and 48b and 
branch conduits 50a and 50b which merge into a conduit 51 in probe section 
24. Pumping pressure is supplied by an inflation pump 54 mounted as shown. 
An initial phase of the earth formation examination technique of this 
invention involves a cleaning operation whereby the bore hole wall surface 
to be observed is sprayed with a suitable cleaning substance to remove 
foreign matter which would impede the visual observations to be made. For 
this purpose cleaning jets 58a and 58b are provided and are shown in FIG. 
3 to be arranged substantially above what might be termed the operating 
end of the probe assembly or above openings 33a and 33b. As best shown in 
FIG. 4, the spraying action of these jets occurs somewhat above the 
portion of the bore hole wall to be viewed so that the spraying action and 
gravity will have the effect of cleaning the entirety of the viewed 
portion of the bore hole wall. 
Jets 58a and 58b, via branch coupling 59, are in fluid communication with a 
pump 62 through conduit 60. Pump 62 receives the cleaning substance, which 
in this embodiment is salt water, via a conduit 64 which is connected to a 
first tank in section 22 of the probe assembly by means of fluid coupling 
66. 
A second aspect of the inventive technique involves the spraying of a 
colorant material onto the surface of the bore hole wall portion being 
viewed. This colorant material is stored in a second tank portion of probe 
assembly section 22 to which is connected a fluid coupling 68. This fluid 
coupling, via conduit 70, supplies the colorant to a pump 72 which in turn 
supplies the colorant material under pressure to conduit 74. The latter 
conduit is divided into branch lines 75a and 75b which are, respectively, 
in fluid communication with jets 76a and 76b. The colorant is described in 
greater detail hereinbelow. 
Each of the pumps 54, 62 and 72 are operated from a power source 78 which, 
in this embodiment, is mounted near the upper end of probe section 24. It 
will be noted that the complex wiring harness exiting from power source 78 
is connected to operate both the pumps and solenoids 82 and 84. The latter 
solenoids, respectively, control the flow of the respective fluid 
materials to pumps 62 and 72. The operation of power source 78 and 
solenoids 82 and 84 can be controlled in a conventional manner from the 
remote control station in van 10 via the wiring harness 81. 
FIG. 4 illustrates the operation of the cleaning and colorant jets and 
their relation to the operation of the remainder of the system. This 
figure illustrates a cut-away section of probe section 26, or that portion 
of the probe section facing a bore hole wall section 86. When this section 
of the probe assembly is placed adjacent wall section 86, the initial 
operation which occurs is the expansion of the bellows followed by the 
spray cleaning operation from, in this case, jet 58b. The bellows 30 is 
inflated through jets 48a and 48b to isolate wall section 86, but a seal 
is not formed. Thus, the sprayed salt water impinges on the wall section 
after proceeding around the outer edge of the extended bellows. 
Another phase of the operation following the extension of bellows 30 
involves the spraying of a colorant material on wall portion 86, and this 
occurs through jets 76a and 76b. 
The figure also illustrates the quartz light 44b which is actuated 
following the spraying of the colorant material to provide the visual 
indication discussed in greater detail hereinbelow. 
In order to carry out a well logging operation in accordance with this 
invention it is contemplated that the probe assembly 14 will be lowered 
into bore hole 18 to the bottom thereof. Then, perhaps using drillers' 
logs, the probe will be raised to predetermined levels within the bore 
hole in order to carry out the observation techniques to be described in 
the following. 
When the probe assembly 14 has been raised to a level having an earth 
formation to be examined, the bellows is expanded as described above. 
Subsequently, pump 62 is actuated, and solenoid valve 82 is opened to 
permit the flow of the cleaning chemical to jets 58a and 58b. The wall 
surface to be examined is then cleaned by means of the high pressure spray 
issuing from jets 58a and 58b and through the solvent action of the 
material as it flows down the wall surface through the force of gravity. 
At this point, ultraviolet lights 44a and 44b are turned on, and the 
operation of the video camera 34 is initiated. These operations are, of 
course, initiated remotely in van 10 by conventional switching means. It 
has been found that when petroleum hydrocarbon molecules are illuminated 
with ultraviolet light a unique color characteristic will be produced in 
the reflected light. This reflected light is received through the lens 36a 
and 36b of camera 34 and by conventional electrical means is communicated 
to the viewing screen 17 in console 16. This provides a clear indication 
of the presence of oil in the earth formation being examined. 
If it has been determined that oil is present in the earth formation being 
examined, it is then desirable to determine its degree of presence, e.g., 
the ratio of oil to water there present. For this purpose solenoid valve 
84 is opened to allow the flow of colorant to pump 72, which is also 
actuated, so that a spray of colorant material issues from jets 76a and 
76b. The colorant is selected to be a material which will not dilute in 
water and adheres to the molecules of the substance, the presence of which 
is being determined. In the case of operations where the presence of oil 
is to be determined, adherence to the hydrocarbon molecules is desired. 
Thus, the more of such hydrocarbon molecules which are present, the 
greater the degree of adherence of the colorant material. Further, a 
material may be selected which has a relatively neutral color but which 
has the effect of fluorescing when in adherence with hydrocarbon 
molecules. In this preferred embodiment the colorant is a lyophilic dye 
and preferably an aniline dye. The latter dye is formed, in a specific 
example, from a mixture of aniline black in an organic solvent, such as 
toluene or zylene. The proportion of these materials are chosen to form a 
mixture having a proper viscosity for spraying, while having sufficient 
aniline black to perform the dyeing function. 
Quartz lights 44a and 44b are turned on during this spraying operation. The 
video camera 34 is again actuated and the color intensity of this scene 
may then be observed. By reason of the aforementioned adherence action of 
the colorant material, the greater the intensity of the known color, the 
greater the degree of presence of oil in the oil-water mixture. Therefore, 
by this means, the degree of presence of oil can be readily and 
immediately determined simply by visual inspection via viewing screen 17. 
The entire operation described hereinabove may be repeated as many times as 
necessary at different depths in the bore hole as selected by conventional 
geological techniques. 
While the invention described hereinabove has been described primarily from 
the standpoint of its use in locating petroleum deposits, it is 
contemplated that these principles may be applied to the location of other 
substances or materials. Further, it is contemplated that other selections 
of light frequencies may be used or that other specific chemical materials 
may be found to be useful to achieve the same ends. 
It should, therefore, be remembered that although the invention has been 
described in connection with a specific application and a preferred 
embodiment, the description in the specification is considered to be only 
exemplary. Numerous changes in the construction of the apparatus described 
hereinabove and modifications in the selection of light frequencies and 
chemicals and the like may be resorted to without departing from the 
spirit and scope of the invention defined in the appended claims.