Apparatuses and methods for making geophysical measurements useful in determining the deflection of the vertical

• US 5,112,126 A
• Filed: 07/27/1990
• Issued: 05/12/1992
• Est. Priority Date: 07/27/1990
• Status: Expired due to Fees

• Current Assignee: Chevron Research And Technology Company (Chevron Corp.)
• Original Assignee: Chevron Research And Technology Company (Chevron Corp.)
• Inventors: Graebner, Peter
• Primary Examiner(s): Buczinski, Stephen C.
• Application Number:
  US07/558,931
• Time in Patent Office: 655 Days
• Field of Search: 340/854, 356/141, 356/152, 356/148, 356/149, 356/250, 33/282, 33/283, 33/302, 33/304, 33/306, 33/308, 33/309, 33/314, 73/151, 250/261, 250/265
• US Class Current: 356/141.5
• CPC Class Codes: E21B 47/0236 using a pendulum
• CPC Class Codes: G01B 11/26 for measuring angles or tapers; for testing the alignment of axes
• CPC Class Codes: G01C 15/10 Plumb lines
• CPC Class Codes: G01C 9/14 movable in more than one direction

Abstract

A non-magnetic apparatus is disclosed for finding the deflection of the vertical. That apparatus has a device for finding an instrument spatial angle between a reference direction and an instrument characterization direction, and a device for finding a deflection spatial angle between the instrument characterization direction and a direction along a plumb line. Preferably, the device for finding the instrument spatial angle uses a system of gyroscopes. Preferably, the device for finding the deflection spatial angle uses a pendulum.

Claims

1. A non-magnetic apparatus comprising:

(a) means for finding an instrument spatial angle between a reference direction and an instrument characterization direction, wherein the means for finding said instrument spatial angle comprises a gyroscope, and

(b) means for finding a deflection spatial angle between said instrument characterization direction and a direction along a plumb line, wherein the means for finding a deflection spatial angle is attached to the means for finding an instrument spatial angle.

2. An apparatus according to claim 1 wherein said means for finding said deflection spatial angle comprises a pendulum.

3. An apparatus according to claim 2 wherein said means for finding said deflection spatial angle further comprises:

(a) a unidirectional light source attached to said pendulum; and

(b) a system of light sensors positioned to detect the direction of the light from said light source.

4. An apparatus according to claim 3 wherein:

(a) said system of light sensors has, within its center, a target light sensor; and

(b) said means for finding the deflection spatial angle further comprises;

(1) means to move said system of light sensors so as to maintain a constant orientation with respect to said pendulum; and

(2) means for monitoring the orientation of said system of light sensors.

5. An apparatus according to claim 2 wherein said means for finding said deflection spatial angle comprises:

(a) a system of light sensors and unidirectional light sources contained within a single plane;

(b) a reflective means attached to said pendulum that reflects light in a non-perpendicular manner;

(c) a means to move said system of light sensors and light sources so as to maintain a constant orientation with respect to said pendulum; and

(d) a means for monitoring the orientation of said system of light sensors and light sources.

6. An apparatus according to claim 5 wherein said light sensors comprise light-sensitive diodes.

7. An apparatus according to claim 5 wherein said system of light sensors and light sources is located on the inner portion of a shell that is at least partly spherical.

8. An apparatus according to claim 1 further comprising a second means for finding said deflection spatial angle, wherein the direction determined by said means for finding said deflection spatial angle of section (b) of claim 1 is used as a first approximation of the deflection spatial angle.

9. An apparatus according to claim 1 further comprising means for finding a reference spatial angle between the perpendicular to a reference spheroid and the reference direction.

10. A method for determination of the deflection of the vertical comprising:

(a) finding a reference spatial angle between the perpendicular to a reference spheroid and a reference direction;

(b) finding an instrument spatial angle between said reference direction and an instrument characterization direction;

(c) finding a deflection spatial angle between said instrument characterization direction and a direction along a plumb line; and

(d) adding together said reference spatial angle, said instrument spatial angle, and said deflection spatial angle.