Gyroscopic directional surveying instrument

• US 4,302,886 A
• Filed: 10/29/1979
• Issued: 12/01/1981
• Est. Priority Date: 10/29/1979
• Status: Expired due to Term

• Current Assignee: Computalog, Ltd. (Precision Drilling Corporation)
• Original Assignee: Robert L. Fournet
• Inventors: Starr, George N.
• Primary Examiner(s): Martin, Jr., William D.
• Application Number:
  US06/088,959
• Time in Patent Office: 764 Days
• Field of Search: 33/304, 33/312, 33/302, 33/313, 33/310, 33/309, 33/350, 62/259 R, 62/259 A, 250/256, 250/254, 250/268, 73/431
• US Class Current: 33/312
• CPC Class Codes: E21B 47/022 of the borehole, e.g. using geomagnetism

Abstract

Apparatus used for the directional surveying of deep wells, i.e., 20,000-25,000 feet (6,096 meters-7,620 meters), and which is specifically identified as a gyroscopic directional surveying instrument having a high pressure and a high temperature capability, e.g., 24,000 pounds per square inch (1,632.65 atmospheres) and 450° F. (232.22° C.). While in its fully assembled configuration, the apparatus may be described as being exceptionally long (or at times unwieldy), e.g., 12-16 feet long (3.66 meters-4.88 meters), it is quite remarkable that it does not exceed three inches (76.2 millimeters) in diameter. Therefore, it may readily be lowered into the small diameter steel casing normally defining the walls of these deep wells. In view of its cumbersomeness, it is significant to note that the apparatus may readily be broken-down into upper and lower sub-assemblies when being transported to or from the well site. Moreover, structure is included for individually protecting each sub-assembly from the adverse affects of the extreme pressure and temperature. Therewith, the feasibility of "on site" mating and demating of these sub-assemblies is achieved. Equally significant is that structure is included which readily enables the required physical access--at the " on site" location--to the internally disposed gyrocompass, inclinometer, and camera systems, i.e., for the purpose of accomplishing certain initial preparations and/or calibration procedures.

Claims

1. An improved well surveying apparatus comprising, in combination, a gyroscopic directional instrument system, and isolation means for maintaining, at least for a reasonable period of time, a suitable internal environment in which said gyroscopic directional instrument system may reliably function while being exposed exteriorly to an extremely hostile environment known to exist at the lower reaches of deep wells which extend several miles into the surface of the earth, said gyroscopic directional instrument system including electric motor means for driving a gimbal arrangement and a first power supply for providing a principal source of electromotive force (EMF) for powering said electric motor means;

said isolation means including heat sink means for absorbing, within limits, the heat being generated by said electric motor means as power from said first power supply is being dissipated in the process of maintaining optimum revolutions-per-minute (RPM) of said gimbal arrangement, said heat sink means including a first mass of metal disposed adjacent said electric motor means and a second mass of metal shaped so as to be disposed adjacent said first mass of metal and said electric motor means for readily conducting heat from one to the other;

said second mass of metal (constituting in part said heat sink means) being tubular shaped, said first and second masses of metal being compatible in size and shape to enable a portion of said tubular shaped heat sink means to be slip fitted over said first mass of metal;

said heat sink means including quick disconnect fastener means for;

(1) rigidly joining said first and second masses of metal together, and (2) facilitating expediency in separating said first and second masses of metal one from the other.

2. The combination as set forth in claim 1 in which said quick disconnect fastener means includes spring loaded plunger means attached to said first mass of metal and an aperture provided in said tubular shaped mass of metal, said plunger means and said aperture being arranged to selectively enable said plunger means to be made to register close fittingly with said aperture when said tubular shaped mass of metal is properly slip fitted over said first mass of metal thus precluding inadvertent separation thereof.

3. An improved well surveying apparatus comprising, in combination, a gyroscopic directional instrument system, and isolation means for maintaining at least for a reasonable period of time a suitable internal environment in which said gyroscopic directional instrument system may reliably function while being exposed exteriorly to an extremely hostile environment known to exist at the lower reaches of deep wells which extend several miles into the surface of the earth, said isolation means comprising heat shield means for protecting said gyroscopic directional instrument system from the extremely hot temperatures inherently existing in said hostile environment, and interface switch sub means for enabling said apparatus to readily be broken down into upper and lower sub-assemblies to facilitate transporting said apparatus between a laboratory-like environment and a well-field environment;

said gyroscopic directional instrument system including electric motor means for driving a gimbal arrangement and a first power supply for providing a principal source of electromotive force (EMF) for powering said electric motor means;

said apparatus having inclinometer means and camera means and having a second power supply for providing a second source of electromotive force (EMF) for powering certain typical operations of said camera means;

said electric motor means, said inclinometer means, and said camera means being compatibly interarranged to establish a first group of component members disposed within said upper sub-assembly;

said first power supply including numerous individually cased battery cell members compatibly arranged to establish a second group of component members disposed within said lower sub-assembly;

the outer circumference surface of said interface switch sub means, being interposed between said upper and lower sub-assemblies, constituting a medial portion of the outer surface of said apparatus resulting in said interface switch sub means being directly exposed to the extremely hot temperatures;

said isolation means including interface switch sub heat insulation means for minimizing any heat transfer upwardly from said interface switch sub means to said first group of component members, and battery pack heat insulation means for minimizing any heat transfer downwardly from said interface switch sub means to said second group of component members, thus the temperature of said first and second groups of component members is not adversely affected by any rise in temperature of said interface switch sub means.

4. An improved well surveying apparatus comprising, in combination, a gyroscopic directional instrument system, and isolation means for maintaining at least for a reasonable period of time a suitable internal environment in which said gyroscopic directional instrument system may reliably function while being exposed exteriorly to an extremely hostile environment known to exist at the lower reaches of deep wells which extend several miles into the surface of the earth, said isolation means comprising heat shield means for protecting said gyroscopic directional system from the extremely hot temperatures inherently existing in said hostile environment, and interface switch sub means for enabling said apparatus to readily be broken down into upper and lower sub-assemblies to facilitate transporting said apparatus between a laboratory-like environment and a well-field environment;

said heat shield means including an upper vacuum flask constituting a part of said upper sub-assembly for encompassing and heat shielding a first group of component members of said apparatus, and a lower vacuum flask constituting a part of said lower sub-assembly for encompassing and heat shielding a second group of component members of said apparatus, thus each of said sub-assemblies is independently shielded from the extremely hot temperatures;

said gyroscopic directional instrument system including electric motor means for driving a gimbal arrangement and a first power supply for providing a principal source of electromotive force (EMF) for powering said electric motor means, said first power supply being disposed within said lower sub-assembly thus being encompassed by said lower vacuum flask;

said first power supply including numerous individually cased battery cell members arranged in series thus establishing a long string of battery cell members having considerable weight, and said apparatus including load-transition means for precluding any inertia loads (attributable to the weight of the string of battery cell members) from acting adversely upon said lower vacuum flask;

said load-transition means including battery tube means for containing the string of battery cell members, said battery tube means being disposed within said lower vacuum flask, said load-transition means including support means for supporting said battery tube means merely from the upper end thereof, thus said battery tube means totally depends from said support means and extends downwardly into said lower vacuum flask;

said load-transition means including shock absorber means disposed at the closed bottom of said battery tube means with the lowermost one of said string of battery cell members being restingly supported by said shock absorber means;

said lower vacuum flask being formed from a substance which readily conducts electricity;

said battery tube means including (at least in part) means for providing electrical continuity between the lowermost one of said string of battery cell members and said lower vacuum flask, thus said vacuum flask may be utilized for providing, at least in part, an electric circuit for interconnecting said electric motor means and said first power supply;

said battery tube means including an intermediate tubular member interposed between upper and lower sleeve-like members, both of said sleeve-like members being provided with internally threaded portions with said upper internally threaded sleeve-like member constituting, at least in part, said support means;

the remote ends of said intermediate tubular member being fixedly attached respectively to said upper and lower sleeve-like members and having the internally threaded portions thereof outwardly directed, and said battery tube means also including contact plug means provided with an externally threaded portion for threadedly engaging said lower internally threaded sleeve-like member thus providing means for closing the bottom of said battery tube means, said shock absorber means including load-bearing compression spring means restingly supported by said contact plug means;

thus the weight of said long string of battery cell members is initially carried by said load-bearing compression spring means, thence by said contact plug means;

thus the weight of said long string of battery cell members is initially carried by said load-bearing compression spring means, thence by said contact plug means (which depends from said lower sleeve-like member), thence longitudinally upwardly along said intermediate tubular member where it is finally carried by said upper sleeve-like member which constitutes, at least in part, said support means.

5. The combination as set forth in claim 4 in which said circuit means includes a contact head member for engaging and thus establishing an electrical contact with the lowermost one of said battery cell members, said contact plug means includes inwardly and outwardly directed cup-like portions communicated one with the other by an aperture provided therethrough, said load-bearing compression spring means being disposed at least in part within said inwardly directed cup-like portion and engaging said contact head member for making an electrical circuit between said contact head member and said contact plug means, said lower vacuum flask having a somewhat fragile closed bottom which is incapable of assuming any of said inertia load, said contact plug means being disposed adjacent to said fragile closed bottom although having a definite spaced distance between the bottom of said lower vacuum flask and said contact plug means, said circuit means also includes electrical conductor non-load-bearing compression spring means disposed at least in part within said outwardly directed cup-like portion and which bears against both of said contact plug means and the fragile closed bottom of said lower vacuum flask, and fastener means having a portion extending through said aperture for attaching said load-bearing and electrical conductor non-load-bearing compression springs one with the other, thus the electrical continuity between the lowermost one of said string of battery cell members and said vacuum flask is provided.

6. An improved well surveying apparatus comprising, in combination, a gyroscopic directional instrument system, and isolation means for maintaining at least for a reasonable period of time a suitable internal environment in which said gyroscopic directional instrument system may reliably function while being exposed exteriorly to an extremely hostile environment known to exist at the lower reaches of deep wells which extend several miles into the surface of the earth, said isolation means comprising heat shield means for protecting said gyroscopic directional instrument system from the extremely hot temperatures inherently existing in said hostile environment, and interface switch sub means for enabling said apparatus to readily be broken down into upper and lower sub-assemblies to facilitate transporting said apparatus between a laboratory-like environment and a well-field environment;

said gyroscopic directional instrument system including electric motor means for driving a gimbal arrangement and a first power supply for providing a principal source of electromotive force (EMF) for powering said electric motor means;

said isolation means including heat sink means for absorbing, within limits, the heat being generated by said electric motor means as power from said first power supply is being dissipated in the process of maintaining optimum revolutions-per-minute (RPM) of said gimbal arrangement, said heat sink means including a first mass of metal disposed adjacent said electric motor means and a second mass of metal and said electric motor means for readily conducting heat from one to the other;

said second mass of metal (constituting in part said heat sink means) being tubular shaped, said first and second masses of metal being compatible in size and shape to enable a portion of said tubular shaped heat sink means to be slip fitted over said first mass of metal;

said heat sink means including quick disconnect fastener means for;

(1) rigidly joining said first and second masses of metal together, and (2) for facilitating expediency in separating said first and second masses of metal one from the other.