DE3230889A1 - Improvements on or in devices for measuring the direction of a borehole - Google Patents

Description

DESCRIPTION:

The invention relates to devices for monitoring or measuring the direction of a borehole, the Measurement takes place either continuously or at a series of measuring points spaced over the length of the Boreholes are distributed; the invention also relates to methods for surveying a borehole.

A spatial measurement of the course of a borehole is usually obtained from a series of values for the horizontal or azimuth angle and the angle of inclination, which are measured over the length of the borehole. Measurements, the values of which are for both angles can be derived, are carried out at successive measuring points over the course of the borehole, the distances between two adjacent measuring points are precisely known.

In a borehole in which the earth's magnetic field is not due to the existence of the borehole itself is changed, measurements of the components of the gravitational and magnetic fields in the direction of the earth can be made Axis fixed to the pipe can be used to obtain values for the azimuth and the inclination angle, with the Azimuth angle measured against a fixed magnetic reference point, e.g. the magnetic north pole will. In cases, however, in which the geomagnetic field changes due to local conditions in a borehole If, for example, the borehole is lined with a steel pipe, magnetic measurements can be made can no longer be used to determine the azimuth angle with respect to a fixed reference point. A gyro must be used in these circumstances.

32308Ö9

Patent Specification No. 1,509,293 describes such a device having a housing, the longitudinal axis of which in use coincides with the axis of the borehole, a gyro with one degree of freedom having an outer frame mounted in the pipe with its axis coincident with the longitudinal axis the pipe collapses; In addition , the device has a first or inner frame which is suspended in the outer frame so that its axis is perpendicular to the axis of the outer frame , then a rotary rotor mounted in the inner frame, a device for measuring the angular movement of the inner frame with respect to the outer frame and a device which applies a torque to the outer frame to rotate it around its axis so that the inner frame präzediere back into its original position, further Einrich lines for measuring the angle of rotation of the tube about its longitudinal axis relative to the outer frame and a gravity meter for measuring three components of gravity in three directions not in one plane.

This device has proven to be extremely reliable in practice and has an accuracy of up to about + 0.1 ° tilt angle and +1.0 "azimuth angle. The fixed Maximalnexgung for this type of device is usually about 70 ° to the Verticals indicated, since measurements at angles greater than 60 ° with increasing inclination will result in few accurate measurements . However, with the tendency to drill at high inclination angles, there is a growing need for a device whose azimuth accuracy is in the same order of magnitude as that which can be achieved at angles of inclination .

The object of the invention is to create such a device.
35

According to the invention, a device or a device for measuring the direction of a borehole is provided, characterized by a long pipe, the longitudinal axis of which

coincides with the axis of the borehole during operation, by an outer frame rotatably mounted in the piping, whose axis of rotation coincides with the longitudinal axis of the piping coincides, through a gyro mounted in the outer frame, of the output signals for the rotational speeds generated around the axis of the outer frame and an axis lying transverse to this, then by a torque transducer that applies a torque to the outer frame, a first actuator for actuating the Torque transmitter, when the device is arranged at the mouth of the borehole, about the transverse axis in an east-west direction depending on the rotation speed to align the transverse axis, which is caused by the gyro is measured, then by a second actuator, which the torque transmitter as a function of the rotational speed actuated around the axis of the outer frame, the rotational speed being tapped by the gyro when the device is moved along the borehole to stabilize the outer frame in its axis is, and finally by a gravity meter, which shows the two components of gravity in the scans or measures in both transverse directions.

The use of a two-axis rate gyro enables an accuracy of greater than + 0.1 * angle of inclination and + 0.2 ° azimuth angle. A gyrocompass method can be used to align the outer frame for geographic murder, eliminating the need for the methods currently used in conventional gyroscopes to relocate the housing, which can be a major source of azimuth error. For angles of inclination greater than 45 °, can the external angle be subjected to torque in order to keep the angle of the upper side at zero? the speed measurement of the gyro about the transverse axis can be used to calculate the azimuth when the device is on

4th
the path of the borehole is moved. "V

According to the invention, there is also a method for measuring

of a borehole, characterized by an | bring a measuring device at the bottom of the borehole, which has a long pipe, the longitudinal axis of which <\

coincides with the axis of the borehole, through an outer frame rotatably mounted in the pipe, its axis of rotation coincides with the longitudinal axis of the pipe and a gyro mounted in the outer frame, whose output signals the rotational speeds around the axis of the outer frame and one that is transverse to this Show axis, the speed of rotation around the transverse axis measured by the gyro and a torque is applied to the outer frame depending on the measured speed, around the transverse axis To align an east-west direction, move the logger along the borehole, ongoing Measurement of the speed of rotation around the outer frame axis with a gyroscope as the device is moved down the borehole and applying torque on the outer frame depending on the measured speed, around the outer frame in its axis to stabilize by continuously measuring two gravity components in two transverse directions with respect to the outer frame or the pipe and determining at least one of the dip and azimuth angles of the borehole at a plurality of Measuring points calculated along its length from the scanned gravity components.

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The invention is explained in more detail below with reference to two preferred exemplary embodiments. All in the Features and measures contained in the description can be essential to the invention. The painting demonstrate:

1 shows a schematic perspective illustration of a first device, the tube or housing of which is shown in section, FIG. 2 shows a partial section of a dynamically balanced gyro which is part of the

first establishment is

FIG. 3 shows the implementation or transition between two sets of reference axes,

Figure diagrams showing the various 4 to 6 transition stages of Figure 3, Figure 7 is a diagram showing the relationship between the two sets of reference axes .

According to Figure 1, the device within a tubular housing 10, whose longitudinal axis coincides with the axis of Borehole coincides with a dynamically balanced gyro 12 with two degrees of freedom, which is in the outer frame 13 is rotatably mounted on an outer frame shaft 14, this with upper and lower outer frame bearings 16 and 18, which are provided by upper and lower outer bearing fixtures or outer bearing shells 17 and 19 being held. The balanced gyro 12 has a gyro wheel 46, the figure axis of which is perpendicular to the outer frame axis, a first axis of rotation perpendicular to the figure axis and a second perpendicular the axis of rotation arranged to the first axis of rotation, which is also transverse to the axis of the figure. The outer frame shaft 14 is also available with a torque motor 22 and a resolver (coordinate converter) mounted in a resolver bearing 28 Mistake. The resolver 26 has a stator with two coils, the axes of which are at right angles is arranged to each other and a rotor with a corresponding pair of each other at right angles arranged coils. If a reference signal is applied to one of the rotor coils and the other rotor coil is applied

Ground, where the output signals of the two coils on the stator are a and b, then a / b is equal to the Tangent of the angle {L between a reference direction with respect to the tube 10 and a reference direction with respect to the outer frame shaft 14. The device also has a gravity meter 30 composed of three accelerometers mounted on the outer frame shaft 14 consists.

According to Figure 2, the dynamically balanced gyro

12 a housing 32 which is fastened to the outer frame 13 is, one opposite to the housing 32 and the outer frame

13 about the figure axis 35 rotatable shaft 34 which is provided with figure axle bearings 36, and a drive motor 40 with a rotor 42 attached to the shaft 34 and a stand 44 attached to the housing 32. Das The impeller 4 6 is connected to the shaft 34 by a universal joint coupling, the universal joint coupling has an inner frame 48 which is rotatably mounted about the first axis of rotation by torsion springs 50, extending between the shaft 36 and the inner frame, the impeller 46 also being rotatable about the second axis of rotation running perpendicular to the first axis of rotation is rotatably supported by torsion springs 52 extending between the inner frame 48 and the gyro frame 46.

The impeller 46 has a permanent ring magnet and a circular recess 56, the immediate

O b _{ar is arranged} next to the permanent ring magnet 54 and in which four torque transducer coils 57 to 60 extend, which are attached to the housing 32, the coil 57 of the coil 59 and the coil 58 of the coil 60 each being diametrically opposite. A plurality of taps 62 attached to the housing 32 measure the angular displacement

of the impeller 46 about two mutually perpendicular axes. In operation, the torque applied to the gyro wheel 46 by the torsion springs 50 and 52 is canceled out by the negative torque that results from the dynamic effect of the inner frame 3 48, which is how the square root of the speed of the impeller 46 changed. Therefore there is only one speed, i.e. the balancing speed, at which the positive spring torques are canceled out by the dynamic effect. at At the balancing speed, the gyroscope 46 is disengaged from the shaft 34 and thus acts as a free gyroscope.

Figure 3 is a schematic representation of a borehole 80 having multiple reference axes opposite which the alignment direction of the borehole 80 can be set »and the contain a family of earth-fixed axes ON, OE and OV, where OV vertically downwards, ON due north and OE is oriented exactly to the east and a group of axles fixed to the pipe OX, OY and OZ, where OZ is the local borrowed direction of the borehole at the measuring station ent elongated and OX and OY j-swells in vertical planes lie to that direction. The family of axles fixed to the earth can be converted into the family of axles fixed to the pipe by the following three clockwise or clockwise rotations to be rotated:

1) Rotation around the axis OV through the azimuth angle ¹ U / * (Figure 4),

2) Rotation about the axis OE ₁ through the angle of inclination θ (Figure 5),

3) Rotation about the axis OZ through the angle at the upper pipe mouth 0 (Figure 6).

FIG. 7 schematically shows the relationship between the axles fixed to the pipe OX, OY and OZ and a group of axles OX ', OY' and OZ ¹ fixed to the outer frame, the axes OZ and OZ * coinciding and with in the figure

OZZ ^{1 are} designated. This figure also shows the relationship between the upper mouth side angle 0 and the angle 0 ... measured by the resolver 26, where 0, the mouth side angle, which would result if the device were to a measuring point without rotation about the fixed axis OZ would be proceeded. 0 ₂ obviously depends on the shape of the trajectory being followed by the device. Thus 0 = 0- + 0 ₂ , if the pipe-fixed, earth-fixed and outer frame fixed axes coincide at the mouth of the borehole.

The three accelerometers of the measuring device are arranged in such a way that they apply the three components of gravity g _VI , g _vl and g n, on the three mutually perpendicular

Λ X u

^{Measure the axes OX 1} , OY ¹ and OZ ¹ fixed to the outer frame, the axis OZ ¹ coinciding with the borehole axis. The three accelerometers can also be mounted on the tube 10 and arranged in such a way that they _{measure the gravitational components g x} , g "and g_ on the three axes OX, OY and OZ fixed to the tube at right angles to one another.

If the accelerometers are mounted on the pipe, then the gravity vector is equal to ^g ~ ⁹ X * V ^g y '"y ^{+ g} Z *" z, ^{f where} S _x # Ü _y and Ü _{z are} the unit vectors in the pipe-fixed axis directions OX, OX and OZ are. If the accelerometers are attached to the outer frame, then the gravity _{vector is equal to g = g x} , .Ü _x , + g _Y , .Ü _y , + g _z , .ü _z ,, where ϋ _χ ,, U and Ü _z , the unit vectors in the directions of the axes fixed to the outer frame are OX ¹ , OY 'and OZ ¹ .

In order to,

g _x i = g _x cos 0 ₁ - g sin 0 ₁ (A)

i ■ g _x sin 0 ₁ + g _y cos 0 ₁ (B)

« ^Sg Z

If U ", ü_ and U" and U, .. unit vectors in the direction

N Ci Ci V

The definition of the angles 0, θ and the vector equation ^ roy = \ _ ψ "} £ θ $ £ 0] Ü _{YV7 represents} the transformation ratio between the families of unit vectors of the two frames represents what

cos

sin τ | γ 0

cos θ 0

-sin θ

-sin-v | r 0 cos \ lr ■ 0 0 1.

0 sin θ

1 0

0 cos 6

te}

and

cos 0 -sin 0 0 sin0 cos 0 0 0 0 1

The vector operation

represents the transformation ratio in the opposite direction represent.

The device can be operated in three different measuring phases in order to obtain three own measured values. First of all, the device can be operated using the gyroscopic measuring method in order to locate an angular reference position of the outer frame 13, the device being arranged vertically at the mouth of the borehole, the axis OZ ^{1 being} aligned with the axis OV. The rotational speed measured by the taps 62 of the balanced gyro 12

speed of the gyro wheel 46 around the axis OX ¹ as a result of the earth's rotation is fed back to the torque transmitter 22 via a corresponding control circuit and is used to track the outer frame 13 until the speed of the earth's rotation about the axis OX ¹ measured by the balanced or tuned gyro 12 is zero is when the figure axis 35 (axis OY ') must lie north-south and the axis OX east-west. This meridional gyrocompass phase enables one method of reference alignment of the pipe to be eliminated, since this is currently used in conventional gyroscopes and may be a major source of azimuth error.

In a second measuring method, which applies to borehole inclinations between zero and 45 ° to the vertical, the inclination of the borehole is measured either continuously or at a series of measuring points over its length according to the measuring method described in patent specification No. 1 509 293, except that the reference point for the initial alignment is obtained according to the above description of the first measuring phase or the first measuring process. ^{The rotational speed of the gyro wheel 46 about the axis OZ 1} measured by the taps 62 of the balanced or coordinated gyro 12 is fed back to the torque transmitter 22 via appropriate control circuits and is used to stabilize the outer frame 13 about the axis OZ ¹ , about the alignment of the axis OY ¹ in the vertical meridian plane. The outer frame 13 thus behaves like a uniaxial ^{platform stabilized about the axis OZ 1} , which coincides with the tube axis OZ. This means that the total rotation of the pipe 10 about the axis OZ, measured with respect to the reference point of the outer frame, is equal to the sum of all rotations of the pipe 10 about the instantaneous directions of OZ when the device is laid along the path of the borehole and that it is clear -

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tig is independent of the trajectory being followed.

In the device described in patent specification No. 1 509 293, the emigration speeds about the axis OZ in the order of magnitude of 1-10 ° per hour, the emigration speed being checked during the measurement. In this way an accuracy of the emigration speed measurement in the order of magnitude of 0.5 ° / h can be achieved. If, on the other hand, the device is used in the manner described above, an accuracy of the emigration speed in the order of magnitude of 0.1 ° / h can be achieved and there is no need to stop the facility to perform emigration speed tests during the survey. If the system is programmed accordingly to correct the output signals of the accelerometer when the device traverses a non-straight path during the measurement, this measurement phase can be carried out in one continuous operation. In a third measuring phase or a third method, which applies to borehole inclinations greater than 45 ° to the vertical, the outer frame 13 is acted upon by the torque transducer 22, in order to keep the upper mouth angle φ measured by the gravity meter 30 at zero. If the three accelerometers _{measure the gravity components g x} , g _y and g _z along the axis OX, OY and OZ fixed to the pipe, the angle of inclination θ is represented as follows:

θ «atan (g _x , + g _y2 ) / (σ _χ1 + g _yJ + g _z ,) 1/2

and the upper mouth angle θ is represented by:

θ = atan (g _v / -g), YX

where g _x , g _y and g _z corrects for the effects

must be that the device traverses a non-rectilinear path.

The rotational speed of the gyro wheel 46 measured by the taps 62 of the tuned gyro 12 about the axis OX 'can then be used to calculate the azimuth angle "XjT when the device is traveling on the path of the borehole. The rotational speed measured about the axis OX' is equal to Γ _χ = * ο _χ + Jl „, where ^ X is ^{the drill} 9 esc ^ ^windi 9 ^speed <* es device and the axis OX ¹ and» O ^ _v the rotational speed values around the axis OX ^1. Since ψ - zero , the azimuth angle "ViT can be calculated from the time integral" ij / *, where "IjLT - -CO _x / sin θ = - (Γ _χ - * Λ- £) si" θ »where -Λ-'χ ~ ^R _T 'COS "^ * cos θ + R ^ · sin Q, R, p» R _E

R _R = R _E »sln JX. , where Rg is the speed of the earth's rotation around its axis and A> the geographical latitude.

_ _Λ DLe second and third measuring phases complement each other for inclinations greater than 45 ° to the vertical, the second measuring phase would strive to achieve increasingly imprecise results with increasing inclination, while for inclinations from zero to 45 ° to the vertical the

_. third measurement phase increasingly inaccurate results with decreasing Inclination would result.

If the device is moved in such a way that its longitudinal axis OZ ¹ remains parallel to the borehole _{axis during the process, 3} Q then no rotational speeds around the axis fixed to the pipe are given as co _v , co ν and co ″. If the momentary

Λ X ti , ♦

Rotational speed are given as speeds θ and "ψ", which result from changes in the borehole parameters © and "ψΓ, when the device is moved along the largest borehole path, then the rotational speed of the device can be represented in the earth-fixed frame as follows:

ft * 1 »

Rp = - θ · sin γ * «u _N

Operating the vector R to transform it into pipe-solid components yields:

. "^ P + 4.sin0) · ϋ _χ + (are

sin0. ^ ir + 4.COS0) .ü _y

Therefore

_χ ■ -sine-cos0 «liP + 6sin0 (1)

_y »sine» sin0. "Uf + e.cos0 * i2)

₂ «cos © ·" ψ "* (3)

k *

The solution of equations 1 and 2 for "\ lT and θ results in:

γ "-il * _x " cos0 - _Y .sin0J / sine (4)

Q ■ ⁱ ^ _x «sin0 + _y .cos6 (5)

If the magnitude of the speed of rotation of the earth around its axis is equal to K ^ , then the speed of rotation of the earth in a fixed frame can be written as folot

,

the:

. cosA, · ΰ _Ν - Rg-sin ^ Üy or

If one operates the vector R _E in order to transform it into components fixed to the pipe, the result is:

( 10 j 15th . «T> ·« φ * t ·· ·· • 3230889 • 20th 14th T / T.sin0 .. (6) 1
wr 1
Ii
ι ²⁵ ÜL / _X = R_.cos "yCcos © .cos0 + R_.sin9.cos0 - R ₁ J, · sin Y * .COS0 .. (7) Γ
f *
ΐ J-'v = -R ^ .cos \ T.cos9.sin0 - R _D .sin @ .sin0 - R - ,. sin ...(8th), έ I 30 "^ = R -, * cosΤ / Γ * .sin © - R _n .cos © the earth around f
ί
4 35 where _χ , γ and _{2 are} the rotational speeds
represent the axis fixed to the pipe. .. t
ί
4th I. I.

Claims (9)

PATENT CLAIMS 1. Device for measuring the direction of a borehole with a long pipe, the longitudinal axis of which coincides with the axis of the borehole in use, an outer frame rotatably mounted in the pipe, the axis of which coincides with the longitudinal axis of the pipe »with a gyro mounted in the outer frame, a torque transmitter, which applies a torque to the outer frame and with a gravity meter for measuring two gravity components in two transverse directions, characterized in that the gyroscope generates output signals for the rotational speeds around the outer frame ^{axis (OZ 1} ) and an axis (OX ') that is transverse to this and the device turns on has first actuator for actuating the torque transmitter (22), when it is arranged at the mouth of the borehole (80), about the transverse axis (OX ¹ ) as a function of the rotational speed measured by the gyro (12) around the transverse axis (OX ¹ ) to the east -West to direct and that a second actuator, the torque transmitter (22) depending on the from Gyroscope (12) measured rotational speed around the outer frame ^{axis (OZ 1} ) applied when the device is moved along the borehole (80) in order to stabilize the outer frame (13) about its axis (OZ '). 2. Apparatus according to claim 2, characterized in that a resolver (26) for measuring the angle of rotation of the Outer frame (13) is provided about its axis opposite the tube (10). 3. Apparatus according to claim 1 or 2, characterized in that a device (22) for determining the device is provided in the upper mouth angle when it is measured by the gravity components at the borehole (80) is moved along and that a third setting member applied to the torque transducer (22) as a function of the rotational speed measured by the gyro (12) around the transverse axis (OX ¹ ) when the device is moved along the borehole (80) at high angles of inclination, to keep the upper mouth angle (Ji) at zero. 4. Device according to one of the preceding claims »thereby characterized that the gravity ^ knife (30) on Outer frame (13) is attached. 5. Device according to one of claims 1, 2 or 3, characterized in that the gravity meter (30) ara Tube (10) is mounted. 6. Device according to one of the preceding claims, characterized in that the gravity meter (30) measures three components of gravity in three non-coplanar directions. 7. Device according to one of claims 1 to 5, characterized characterized in that the gyro (12) is a dynamic balanced two-axis gyro. 8. A method for measuring a borehole with a logging device comprising a long pipe, the Longitudinal axis coincides with the axis of the borehole, which has an outer frame rotatably mounted in the pipe, the axis of rotation of which coincides with the longitudinal axis of the pipe and also an in Has gyro mounted on the outer frame, characterized in that the gyro has output signals generated for the rotational speeds around the outer frame axis and an axis lying transverse to this, the measuring device being arranged at the mouth of the borehole, the rotational speed around the transverse axis is measured with the gyroscope and a • * ···· tv · Torque is applied in dependence on the measured rotational speed of the outer frame, about the transverse axis to the East-West in that the measurement device at the well is moved along align \ WO at the rotational speed of the outer frame axis from the gyroscope is continuously measured and a torque on the outer frame in Dependence on the measured rotational speed is applied to stabilize the outer frame around its axis, that running two components of gravity measured in two transverse directions relative to the outer frame or the housing and finally the angle of inclination and the azimuth of the borehole at several points above its Length away from the measured gravity components be determined. 9. The method according to claim 8, characterized in that the speed of rotation about the transverse axis is continuous is measured by the gyro when the device is along the Borehole is moved and that a torque on Outer frame is applied depending on the measured rotational speed, around the angle determined from the measured gravity components hold at zero in the upper mouth.