SU1467162A1 - Method of determining azimuth of well crooking - Google Patents

Abstract

This invention relates to field geophysics. The goal is to improve the accuracy of determining the azimuth in the fer-. romagnetic environments. For this, the angle between the selected direction and the horizontal projection of the magnetic field strength vector at the wellhead (C) is measured and fixed. Two sensors (E) of the direction of the horizontal component of the magnetic field strength vector are omitted in C mutually oriented and located one above the other at a distance equal to the measurement interval. At each measurement interval, the upper one. D is located at the location of the bottom. The angle between the axis of sensitivity of the upper axis and the horizontal direction of the vector of a vector at the point of the trajectory C, where the upper D is located, is measured and fixed. The angle gi is measured and fixed. between the axis of sensitivity of the lower one and the direction of the constituent vector at the point of the trajectory C, where the lower D. is located. In areas equal to the measurement interval, the angle Dog is determined and fixed; oi;, 2. -ot ;, turning the vector of the anomalous floor in the horizontal plane. In the curved sections C of the lower D, the magnetic azimuth of the well trajectory is measured and recorded relative to the vector of the anomalous magnetic field. The azimuth of the curvature of the trajectory C relative to the selected direction is determined from the equation o, n ei +, {, 2), where i + f n is the NUMBER of measurement intervals. 4 il. fS (L 4 about: O5 Yu

Description

one

The invention relates to the field of geophysics and can be used to determine the azimuth of the curvature of the well trajectory in ferromagnetic media.

The aim of the invention is to improve the accuracy of azimuth determination in ferromagnetic: -: environments.

Figure 1 shows a device for carrying out the method; Fig. 2 is a vector diagram explaining the essence of the proposed method; FIG. 3 is a vector diagram, based on the operation of the device; Fig. 4 shows a measurement scheme for the proposed method.

.3 1

The method is carried out as follows.

At a distance of 1, equal to the interval (pitch) of measurement J, two identical sensors 2 and 3 are installed one above the other. FIG. 1) the directions of the horizontal component of the magnetic field (for example, fluxgate) so that their axes X and Xj, the sensitivity, are respectively in horizontal 2. planes parallel to each other and when the well deviates from the vertical position were in the plane of inclination of the well, lower the mutually oriented sensors 2 and 3 into the well so that the upper sensor 2 is in the wellhead, where An angle between the horizontal component of the magnetic field and an arbitrarily chosen direction is measured and recorded, against which the azimuth of the borehole trajectory is determined by successive measurements in the well (for example, using the same sensors 2 and 3 of the horizontal component of the magnetic field). , directed the sensitivity axes X, and X, of the sensors 2 and 3 to the chosen direction), and the first measurement was made.

In subsequent measurements during the descent process, at each interval the upper sensor 2 is placed at the location of the lower sensor 3.

The sensors 2 and 3 of the direction of the horizontal component of the magnetic field produce signals proportional to the angles oij between the X axes and X sensitivity of the sensors 2 and 3 and the directions of the horizontal components H and H of the magnetic field at points 0 and ABOUT; well trajectories, where there are sensors 2 and 3, respectively, an angle is measured and recorded at each measurement interval,; and oi;, 4.

If the direction of the horizontal components, the magnetic field And -. ,, and Hj is the same, the difference of the signals from sensors 2 and 3 is zero, but if the direction of the horizontal component of the magnetic field in the gap of the well trajectory between the upper and lower sensors 2 and 3 has changed some angle, the difference of signals from sensors 2 and 3 will be proportional to this value.

62

In the intervals equal to the measurement interval,. the angle uoi is determined and fixed; , i, i rotate the vector of the anomalous magnetic field in the horizontal plane. When borehole curvature occurs, the signals from sensors 2 and 3 are proportional to the magnetic azimuth of the curvature of the borehole trajectory relative to the direction of the horizontal components of the magnetic field vector H, and H to the point of the borehole path O; .., and O, where the respective sensors are 2 and 3, and the difference of signals from sensors 2 and 3 is proportional to the angle Aod; between the horizontal projections of H, -., and H ;.

In the curved sections of the well, the magnetic field azimuth is measured by the lower sensor 3 of the direction of the horizontal component of the magnetic field vector magnetic field (x ;, the curvature of the well trajectory relative to the vector of the anomalous magnetic field, after which the azimuth of the curvature of the well trajectory relative to the chosen direction is determined at points where bottom sensor 3 is located, from equation

oc, oi. + oi ,,

Aoi ;,

(one)

where n is the number of measurement intervals (measurements),.

A device for implementing the method consists of a housing 1 and sensors 2 and 3 of the direction of the horizontal component of the magnetic field, containing frames A and 5, bar 6, inner frames 7 and 8, eccentric weights 9-11, flux probes 12-15, Frames 4 and 5 mounted at opposite ends of the housing 1, with the axes of rotation of the frames 4 and 5 coinciding with the longitudinal axis of the housing 1, the rod 6 connecting the frames 4 and 5 so that they lie in the same plane. Inner frames 7 and 8 are fixed respectively in frames 4 and 5, and the axes of rotation of frames 7 and 8 are perpendicular to the axis of rotation of frames 4 and 5. Eccentric weight 9 is fixed on frame 5, and eccentric weights 10 and 11 respectively on internal frames 7 and 8. Ferrosonde 12 and 13 are located in the plane of the frame 7, with the sensitivity axis of the fluxgate 12 and 13

orthogonal, flux gates 14 and 15 are located in the plane of frame 8 and their sensitivity axes are also orthogonal, with the sensitivity axes of flux glands 13 and 15 coincide respectively with the axes of rotation of the inner frames 7 and 8, and ock the sensitivity of fluxes 12 and 14 are axes sensitivity, respectively, of sensors 2 and 3.

The method is carried out using the device as follows.

In the vertical section of the well trajectory of the frame 4 and 5, rigidly connected by the rod 6, are in the same vertical plane, the eccentric weights 10 and 11 orient the internal frames 7 and 8, respectively, with the flux tubes 12 to 15 in the horizontal planes , and (fig.Z)

Signals}

i

15 respectively with

the flux-gates 12–15 are proportional to the projections H ,,,, H and H, H of the horizontal components of the magnetic field H, -., and H on their sensitivity axis X ,, Y, and X, Y ,. The signals from the flux-probes 12-15 are transmitted via the communication cable 16 (FIG. 4) to the ground control unit 17. These signals calculate the angle between the sensitivity axis of the upper sensor .2 (FIG. O and the direction of the horizontal component of the magnetic field strength vector). the field H ,, and the angle between the axis of the internal sensitivity of the lower sensor 3 and the horizontal direction is equal to the vector of the strength of the magnetic field H;

, Arctg-;,. Arctg.

(2)

Further, taking into account expression (2), the value of &oi;

Aoi- Arctg - Arctg.

and-with-uia

In the curved part of the well trajectory, an eccentric weight 9 (Fig. 2) orients the frames 4 and 5 in a plane perpendicular to the inclination plane, while the sensitivity axes of the sensors 2 and 3 of the direction of the horizontal component of the magnetic field strength vector are 10

4671626

therefore, on curved sections, the Rzven angle of the magnetic azimuth relative to the vector of the anomalous magnetic field.

Thus, by measuring the signals of and, -, and 5- from flux-probes 12-15 according to the proposed method, the angles of JoC are sequentially determined; rotation of the vector of the anomalous magnetic field in the horizontal plane between the points of the well trajectory where sensors 2 and 3 are located. At a distance equal to the measurement interval, a3HMyToin j is measured on the curved section using the lower sensor 3 relative to the vector of the anomalous magnetic field. Summing the angles LOS and taking into account the angle oi-o between the chosen direction and the direction of the horizontal component of the magnetic field strength vector at the wellhead, determine the azimuth of the curvature of the well path relative to the selected direction in accordance with the expression,.

15

20

25

thirty

  o6 „+ o1„, +

Dog ..

To implement the proposed method, a winch 18 (FIG. 4) with a meter counter 19 of cable 16 is installed at the wellhead, at the end of body 1 (FIG. 2), the device is placed at risk so that its direction coincides with the direction of the sensitivity axes of the ferrozonos 12 and 14, the device is lowered into the well so that the part of the housing 1 in which the horizontal direction sensor 2 is located g looking for the magnetic field strength vector is at the wellhead, the device housing 1 is rotated so that the direction p The claims matched the direction chosen for

 readout azimuth of the curvature of the well; after it the first measurement is taken. The signals V g with flux-gates 12 - 15 via cable 16 (Fig. 4) are fed to the ground control

d 17. Using these signals, determine the angle ot-Q between the chosen direction and the direction of the horizontal component of the magnetic field strength vector at the wellhead.

ftd

M

 Arctg

I is the angle d6i of the rotation of the horizontal component of the intensity vector of the magnetic field of the first measurement interval

G Do, 6. -oi ,, - Arctg - - Arctg -.10

Utj, w

and,,

: THROUGH the winch 18 and the meter counter 119 of the cable 16, lower the device to distance 1 (FIG. 1), different distances between sensors 2 and 3 of the direction of the horizontal component of the field strength vector, and determine the angle of rotation burn: ontap component of the magnetic field strength vector of the second measurement interval,; In this way, all subsequent measurements are carried out on the vertical: a part of the well. When a curvature of the borehole is detected by means of a sensor, the 3 directions of the horizontal covariant vector of the field strength are determined by the magnetic 1 O azimuth of the curvature of the borehole relative to the vector of the anomalous magnetic field.

; c6 „, Arctg -,: i i5

Where n is the number of preceding measurement intervals.

The azimuth of the CC curvature of the trajectory of the well relative to the selected

Directions are defined as:

and o6 „Io-us„ h-22 Aoij.

-one

Claims (1)

Thus, the device fully implements the proposed method. Invention Formula The method for determining the azimuth of curvature of a well path in a ferro 0 five 0 five .. five 0 magnetic media, in which a direction is chosen on the surface, relative to which successive measurements in the well determine the azimuth, the intensity of the determination of α-azimuth in ferromagnetic media, and fixing the angle ui | 3 between the selected direction and the horizontal projection of the magnetic field strength vector at the wellhead, two mutually oriented and located one above another at a distance equal to the measurement interval are lowered into the well the horizontal component of the vector magnetic field strength, wherein at each interval upper measuring probe disposed at the location of the lower sensor is measured and fixed ci angle; between the axis of sensitivity of the upper sensor and the direction of the horizontal component of the magnetic field strength vector at the well trajectory point where the upper sensor is located, the angle is measured and fixed (between the sensitivity axis of the lower sensor and the direction of the horizontal component of the magnetic field strength at the point the trajectory of the well, where the lower sensor is located, in areas equal to the measurement interval, determine and fix the angle yy; ° C ;, - the rotation of the vector of the anomalous magnetic field in the horizon on the curved sections of the well with the lower sensor, the magnetic azimuth ci of the curvature of the borehole trajectory relative to the vector of the anomalous magnetic field is measured and recorded, and the azimuth of the curvature of the borehole relative to the chosen direction is determined from the equation and Bp ; and where n is the number of measurement intervals. Phie.1 % /. td P Fig.Z FIG.