SU56318A1 - Well pressure gauge - Google Patents

Description

Pressure measurement in boreholes has so far been carried out by a method in which the discharge element is a piston with a load or spring loading.

The pressure in the well, overcoming the force of the load or spring, moves the piston B to the cylinder. This movement is used either directly as a criterion for the pressure in the well, or to compress the medium (e.g., oil) enclosed in a Bourdon tube (surrounded by atmospheric pressure).

A significant step in both methods is to use a piston, which requires a solid seal in order to avoid leakage of fluid along it, which is completely unacceptable because it distorts the readings of the instrument. Due to the presence of compaction in the piston, even if, as is the case with precision piston gauges, forced rotation is reported (instead of friction, motion friction is obtained), the amount of friction is so great.

which makes the devices inaccurate and completely insensitive.

As with an absolute value of pressure up to 300 atm. Accuracy of the order of a fraction of the atmosphere is required, then (it becomes clear that the use of piston gauges for this purpose is not entirely suitable.

The present invention, in contrast to the foregoing, relates to such devices for measuring pressure in wells, which are based on partial compensation of the measured pressure when using a Bourdon spring, designed for a small measurement limit. This device differs from the known ones in that the chamber in which the Bourdon spring is located is associated with the space, the pressure in which is to be measured, is equipped with a periodically overlapped additional hole, which serves to communicate the cavity of the chamber with the said space. .

In FIG. 1 shows a section through the device, FIG. 2 - recorded pressure charts. The camera / is closed at both ends with covers 2 and 3; In the lower part of the lid 2 there is a recess 15, into which a corrugated membrane 16 is housed. In the middle of the body I, a Bourdon manometer is fixed, the spring 5 of which is designed for low pressure drops of the order of 1-5 atm. In the side wall of the housing / there is a groove p8, into which a corrugated membrane 9 is pressed against each other. The internal cavity of the tube 5a is connected through this drilled hole with this groove. Membranes 9 and / 5 and grids 19 and 20 serve to prevent contamination of the instrument cavity. The axis of the pressure gauge 5 is connected with an electrical sensor of one of the existing constructions C1, with conductors brought out 7. At the bottom of the cylinder / there is a solenoid 10. When current passes through it, the core // stretches the spring 17 and through the lever 72 closes the valve , / 5 hole 14, thereby disconnecting the internal volume 2 / from the external environment. From the solenoid 10, the controlled conductors 18, which are enclosed, like the conductors 7, are brought out into the tube 4. The internal CAVITY of the chamber 1 and the springs 5 are completely filled with a small wire; membranes 9 and. 16, being dividers. Two liquid media transmit, however, without distortion, all pressure changes from the external to the internal environment. The device works in the following way. When valve 13 is open, the instrument is lowered into the well to the required depth. In this case, the pressures inside the Bourdon tube 5 and outside of it in chamber 2 / will always be the same, and the spring will not deform. After that, by pressing the button, the solenoid C is turned off and the valve 13 is closed. At the same time, the medium in cavity 2 / chamber U turns out to be hermetically sealed under the same pressure. If after this the instrument is slowly raised in the well, the pressure along the path of the instrument in the well, fluctuating, will gradually decrease. Since this pressure is permanently transmitted into the interior of the tube 5, the latter is deformed, respectively, of the difference between the pressure in the volume 2 / and in the tube 5. This change will be reflected in the chart recording its potentiometer. At the moment when the reduced pressure reaches the value at which the difference between the pressure in the cavity 27 and the pressure in the well is equal to the limit allowed for the selected sensitive spring of the pressure gauge 5, the maximum relay will operate from sensor 6 and de-energize the solenoid circuit Yu; the valve 13 opens, the pressure in the cavity 2 / is equalized again with the external pressure, and the arrow of the pressure gauge 5 returns to zero. After that, the circuit is closed again, the valve 13 is closed, and, with a further rise of the device up the well, the potentiometer will continue to register the pressure. This diagram will have the form shown in FIG. 2. Arrow jumps across the entire scale indicate the number of shutdowns using the pressure gauge 5- operating pressure range. Choosing this range small enough, you can ensure any desired accuracy of recording changes in pressure in the well. Pre1dmet and hell shadow. 1. A device for measuring pressure in wells, based on partial compensation of the measured pressure when using a Bourdon spring, designed for a small measurement limit, differing in that chamber 1, in which the Bourdon spring is located, is connected to the space, the pressure in which is to be measured It is provided with a periodically overlapped additional opening 14, which serves to communicate the cavity of the chamber / with said space in order to partially compensate for the measured pressure. 2. In the apparatus of claim 1, use corrugated membranes 9 and 16, which serve to protect the chamber / and the Bourdon spring from clogging.

3. in the device on PP. I and 2 use an externally controlled electromagite to act on a spring-loaded lever, which interacts with a valve 13 blocking the opening 14.

Fig1.

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pressure axis

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pressures

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