SU1208211A1 - Apparatus for measuring depth while well-logging - Google Patents

Description

.

The invention relates to a measurement technique and can be used to measure the movement of ferromagnetic products, for example, to measure the depth of descent of a geophysical cable during well logging. The purpose of the invention is to increase the accuracy of the measurement of the depth of the well.

FIG. 1 shows a diagram of the proposed device; in fig. 2 is a section A-A in FIG. 1, in FIG. 3 is a section BB in FIG. 1,

The device consists of a measuring base 1 and a magnetic recording system 2 and reading 3 heads. The scheme for transferring the marks and the counter is not shown in the drawings. The heads are rigidly fixed on the platform 4, which, in turn, is attached to the measuring base 1 (Fig. 1). The measuring base 1 is made telescopic, for which it is made of a group of tubes capable of moving relative to each other. The tube 5 is moved from the tube 6, and the tube b is moved in the tube 7. This allows it to fold in the longitudinal direction and occupy the minimum space during transportation. The restriction of the movement of the tubes occurs due to the presence of stops a and B, respectively, of the lower and upper tubes (Fig. 2).

The cable 8 interacts with the magnetic heads 2 and 3 in the slots and 1, respectively, of the write and read heads (Fig. 3). The measuring base 1 is fixed to the axle; it is attached to the axis 9 of the suspension roller 10, which is fixed by means of the cheek 11

flax on the frame of the drilling rig

12, The arrangement of heads 2 and 3 in the horizontal plane allows for a single cycle of applying magnetic marks to twice transfer the size of the measuring base to the cable. If we conditionally take the length of the measuring base as the mechanical base, and the distance between the centers of the magnetic recording and reading heads along the cable axis over the electromagnetic measurement base, which determines the distance between the magnets, then the proposed device allows you to set magnetic marks at a distance, double the pain. This is more than a mechanical base. And this means that while maintaining the size of the measuring base, the co: quality of its overlays on the cable will be halved. With

eleven

In this case, the accuracy of measuring the cable length and, accordingly, the depth of the wellbore will increase by a factor of ---

where n

and N, respectively, the number of overlaps of the size of the dimensional base by a device in which the mechanical and electromagnetic bases coincide (analogs, - prototype). Since N2 2N, the depth measurement accuracy will increase 47 times,

The device works as follows.

Cable marking and depth measurements are made when the cable is lifted from the well. Having lowered the cable with the downhole device to the bottom, the first magnetic mark is inserted on the cable. Then start lifting the cable. The first mark, moving together with the cable and reaching the reading head 3, will be fixed by it, and the transfer circuit will generate a control signal for setting the second magnetic mark, and the unit will be recorded with a conventional depth code in the counter. If necessary, the output of the counter can be connected to a logging oscilloscope, in which case the depth mark can be found on the logging diagram. The process then continues automatically. The size of the length transmitted by the device to the cable will be expressed

five

0

,

0

t -

where is l

2L + 7g,

- distance from the axis of the guide roller to the centers of the read and magnetizing heads (they coincide); d is the radius of the bending around the axis of the geophysical cable on the roller, This 1 is dimension, i.e. the measure value reproduced by the installation can be measured on the surface with a high degree of accuracy, up to + 0.01% (for example, with a discharge bit pattern III). Taking into account that modern marking systems put marks with an accuracy of + 0.01%, and their principle of operation is similar, while maintaining the length of the measuring base, the accuracy of measurement increases in the end and will be + 0.005%.

D

Thus, the application of the proposed device will allow to increase the g ..: -, the noso measurements and labor productivity.

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Editor Y. Sereda

Compiled by I.Karbachinsk

Tehred m. Parotsay Proofreader V. But ha

212/41 Circulation 548 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Branch PPP Patent, Uzhgorod, Proektna St., 4

(par.Z

Claims (2)

1. MEASUREMENT DEVICE DEPTH DURING A WELL LOGGING, containing a measuring base, rigidly mounted on a hanging roller, magnetizing and reading magnetic heads, a scheme for transferring magnetic marks to a geophysical cable and counter, characterized in that, in order to increase the accuracy of measuring the depth of the well, the centers of magnetizing and reading magnetic heads are installed in a horizontal plane with the ability to interact with ascending and descending branches. geophysical cable. 2. The device. According to p. 1, about l and -, which is due to the fact that the measuring base is made telescopic. Put.t SU „„ 1208211