SU806854A1 - Device for measuring well azimuth - Google Patents

Description

one

The invention relates to exploration techniques and can be used to determine the azimuth of a drilling hole in rocks with magnetic susceptibility.

Instruments are known for determining the spatial position of wells in magnetic media, for example, a gyroscopic inclinometer .1.

The azimuth sensor of this device is made on the principle of a gyroscope and includes a re-chord mounted on a plumb line, which is installed with the possibility of rotation in the bearing supports, and a brush for picking up electrical signals.

The disadvantage of this device is the sensitivities and accuracy of measurements, which is explained by the friction between the brush and the reichord, as well as in the bearing supports. The sensitivity of the sensor is limited by the step of winding the reichord. In addition, wear of the reichord and contamination of the contact between the reichord and the bristles reduces the stability and reliability of the instrument.

A well sensor for the angle of a well gauge measuring device is also known; it contains a source and a light receiver.

a screen mounted between them in the form of a transparent cylinder with an opaque layer of variable width and a plumb 2 applied to its surface.

However, this sensor cannot be used to measure the azimuth of a well in rocks that have a magnetic susceptibility.

The purpose of the invention is to improve the measurement accuracy and sensitivity. To achieve this goal, the device is equipped with a gyroscope mounted in the housing, on the axis of which the screen is placed, and the source and receiver

5 lights are located on the plumb line.

The drawing shows the proposed device.

The device contains a source of light 1, the receiver 2 of the light installed

0 between them is a screen in the form of a transparent cylinder 3 with an opaque layer 4 of variable width and plumb 5 applied to its surface, the source and the light receiver are mounted on the plumb

5 5, the hydroscope 6, and the screen-cylinder 3 is fixed on the axis of the gyroscope 7.

All elements of the device are placed in the housing 8.

Claims (2)

The device works as follows. Before starting measurements on the surface of the earth, the downhole tool deviates from the vertical in a direction whose azimuth is accurately known (relative azimuth). A gyroscope is started which ensures the oriented position of the transparent cylinder 3 with an opaque layer 4 of variable width applied on its surface. With the help of plumb 5, the source 1 of light and the receiver 2 of radiant energy, located in the radial direction relative to the axis of rotation of the plumb, are always oriented in the apsidal plane. At a ground station, which is connected by a logging cable with a downhole tool, a measurement signal is generated, which is a proprietary relative azimuth value. Then, the downhole tool on the cable is lowered into the well and the well azimuth of the well is continuously recorded during both descent and elevation of the device. When the device is moved. In the well, the light source 1 and the light receiver 2 by means of a plumb line 5. permanently occupy a position in the apsidal plane from the well. Since the cylinder under the action of the gyroscope 3 occupies a constant position in space, the light source 1 and the radiant energy receiver 2 under the action of the plumb 5 move relative to the opaque layer 4 by an amount proportional to the azimuth of the well at a given point from the well. a cylindrical surface with a certain width of the opaque layer 4, while the luminous flux from the source of light 1, crosses the corresponding transparent section of the cylinder. 3, arrives at receiver 2 and is converted into an electrical signal transmitted nehkhryrv but to the surface of the earth, the magnitude of this signal determines the azimuth of the well. In the design of the device there is no mechanical connection between the external axis of the gyroscope and the sensor azimuth of the well. on the principle of a gyroscope. The absence of rubbing electrical contacts in the azimuth sensor also increases the sensitivity and stability of the device. The possibility of continuously recording the azimuth of a well on the surface of the earth allows the use of statistical methods for processing measurement information, which significantly increases the accuracy of determining the azimuth of a well drilled in rocks with any magnetic properties. The increase in sensitivity and stability of measurements achieved with the help of this device design makes it possible to more accurately determine the spatial position of the well and take timely measures to prevent the well from deviating from a given direction. This, in turn, is a reserve for improving the efficiency of exploration.:. The invention The device for measuring azimuths sk.vach: ins, containing a body, a source and light, a cylindrical screen with variable optical density between them, a plumb bob, is distinguished by the fact that, in order to improve measurement accuracy and sensitivity, it is equipped with the housing of the gyroscope, on the axis of which the screen is placed, and the source and receiver of light are located on the plumb line. Sources of information taken into account in the examination 1.Vartykin V.T. Diamond drilling of directional and multilateral wells. L., Nedra, 1969, pp.73-85. 2. Author's certificate of the USSR 662703, cl. E 21 B 47/022, 1978.