Well mapping apparatus and method

Claim 2

In apparatus for determining azimuth in a bore hole, a. a rate-of-turn gyroscope sized for travel lengthwise of and within said hole, the gyroscope including a rotor having a spin axis, a carrier frame and a subframe, b. means to support the gyroscope for said travel and to rotate the carrier frame about another axis extending generally in the direction of the hole so that the spin axis is rotated to define a plane normal to said other axis, the sub-frame carried by the carrier frame for yieldable rotation relative thereto about said other axis and the rotor carried by the sub-frame to spin relative thereto and about said spin axis, c. the gyroscope having circuit means for producing an output which varies as a function of azimuth orientation of the rotor spin axis relative to the earth''s spin axis.

Claim 3

The apparatus of claim 1 wherein said first means comprises well tubing operable to rotate the gyroscope carrier frame about said other axis in response to well tubing rotation.

Claim 4

The apparatus of claim 1 wherein said first means includes a motor sized for travel in the hole and operatively connected with the gyroscope to rotate the gyroscope carrier frame about said other axis.

Claim 5

The apparatus of claim 3 wherein said first means also includes a housing supporting and containing said motor and gyroscope, the housing sized for travel in the well.

Claim 6

The apparatus of claim 4 including well tubing freely receiving said housing for lengthwise travel therein, the circuit means operatively connected to the carrier frame and sub-frame to detect relative roTation therebetween.

Claim 7

The apparatus of claim 3 wherein the motor has a rotary output element transmitting continuous unidirectional drive to the carrier frame at a rate less than about 2 rpm.

Claim 8

The apparatus of claim 3 wherein the motor has a rotary output element transmitting cylically reversing rotary drive to the carrier frame.

Claim 9

The apparatus of claim 4 wherein there is servo means responsive to the circuit output to control said motor to maintain the gyroscope rotor spin axis with predetermined azimuth orientation.

Claim 10

The apparatus of claim 4 including other circuitry operatively connected with the motor and housing to produce an output signal indicating azimuthal orientation of the rotating gyroscope carrier frame relative to the housing, whereby said signal and the circuit output may be processed to determine azimuth orientation of the housing relative to the earth''s spin axis.

Claim 11

The apparatus of claim 1 including well logging mechanism also supported by said means.

Claim 12

The apparatus of claim 10 wherein said mechanism comprises instrumentation to quantitatively determine bore hole tilt from vertical.

Claim 13

The apparatus of claim 11 wherein said mechanism comprises a radiometer.

Claim 14

The apparatus of claim 1 including an accelerometer supported and rotated by said means to produce an output which varies as a function of said carrier frame rotation and of the degree of tilt of said other axis from vertical.

Claim 15

The apparatus of claim 13 wherein said means includes a motor connected to rotate the gyroscope carrier frame and accelerometer about said other axis, and a housing supporting and containing the motor, gyroscope and accelerometer.

Claim 16

The combination of claim 14 including other circuitry responsive to said gyroscope circuit means output and accelerometer output to produce an indication of the direction and degree of tilt of the bore-hole at selected depth therein of the carrier frame.

Claim 17

The combination of claim 14 including well tubing in the bore hole and a wire line suspending the housing in the tubing for lowering and elevation therein.

Claim 18

The combination of claim 15 wherein the accelerometer is characterized as having a single degree of freedom and is supported by the housing to have its sensitive axis rotatable into and out of tilt relative to a horizontal plane.

Claim 19

The combination of claim 15 wherein the gyroscope is supported to have its rotor spin axis rotatable into and out of a North-South plane passing through the earth''s spin axis and intersecting said other axis.

Claim 20

In well mapping apparatus, the combination comprising a. a housing to be lowered in a well having an axis, b. a rate-of-turn gyroscope operable in the housing to produce an azimuth indicating signal, the gyroscope including a rotor having a spin axis, a carrier frame rotatable about an upright axis generally parallel to the well, a sub-frame carried by the carrier frame for yieldable rotation relative thereto about said upright axis, the rotor carried by the sub-frame with said spin axis normal to said upright axis, and circuit means to produce said signal as a function of azimuth orientation of the rotor spin axis relative to the earth''s spin axis, and c. an accelerometer rotatable in the housing in conjunction with gyroscope carrier frame rotation to produce a signal indicative of the direction of tilt of the housing from vertical, said signals being so synchronized by virtue of said rotation as to enable derivation therefrom of the true direction of tilt of the housing in the well.

Claim 21

In well mapping apparatus, the combination comprising a. a housing to be lowered in a well having an axis, b. a rate-of-turn gyroscope operable in the housing to produce an azimuth indicating signal, the gyroscope including a rotor having a spin axis, a carrier frame rotatable about an upright axis generally parallel to the well, a sub-frame carried by the carrier frame for yieldable rotation relative thereto about said upright axis, the rotor carried by the sub-frame with said spin axis normal to said upright axis, and circuit means to produce said signal as a function of azimuth orientation of the rotor spin axis relative to the earth''s spin axis, and c. an accelerometer rotatable in the housing in conjunction with gyroscope carrier frame rotation to produce a signal indicative of the direction of tilt of the housing from vertical, said signals being so synchronized by virtue of said rotation as to enable derivation therefrom of the true direction of tilt of the housing in the well.

Claim 22

The combination of claim 19 wherein said housing is generally tubular and defines an axis generally parallel to said upright axis.

Claim 23

The combination of claim 19 including means to multiplex said signals for transmission to the surface.

Claim 24

The combination of claim 19 including drill pipe in the well and a cable supporting said housing in the drill pipe for elevation and lowering therein.

Claim 25

The combination of claim 20 wherein the gyroscope is of single degree of freedom type, and has its rotor spin axis generally normal to the housing axis.

Claim 26

The combination of claim 20 wherein the accelerometer has its sensitive axis generally normal to the housing axis.

Claim 29

The method of claim 25 including the step of carrying out said rotation independently of drill pipe rotation.

Claim 30

The method of claim 25 including the step of carrying out said rotation in conjunction with rotation of the drill pipe.