SU1574182A3 - Method of determining inner volume of cavities, particularly, for example, spaces of cavities, galeries and the like natural formations - Google Patents

Abstract

The invention relates to a method for determining the spatial content of spaces, especially subterranean spaces, such as for example cavities, caverns, caves and the like. The essence of the invention resides in the fact that the volume of a medium filling the space being studied is changed by a sudden and short-lived increase or decrease in volume. In this arrangement, the pressure prevailing in the space before the change in volume is measured, as is also the pressure change which takes place as the effect of the change in spatial content, and then the desired spatial content of the space is determined by calculation from the values measured. As a result, the spatial content of spaces of any desired volume and of widely varying morphology can be determined much more accurately and cheaply than in the past.

Description

V

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, where uV is the specified variation of the volume, and C is the compressibility of the medium.

In addition, in the case of use ™ -. Neither liquid as a cut medium — an explosive decrease in the volume of the medium of the cavity under study is accomplished by abruptly introducing a part of the fluid filling the cavity into a container with a known volume.

A sharp increase in the volume of the medium filling the cavity under investigation, which is united with the surrounding atmosphere, for example, a basement, is carried out by means of a sharp intake of the medium from the gas cylinder using a half-turn valve.

Example I. At the wellhead, a manometer head is fixed with a high accuracy of indication, which can detect a pressure change from as low as 1 Pa. A device is known at the wellhead, known as a half-turn valve, the feature of which is that when the actuator is turned, the valve opens only for a very short time, on. one moment or a few moments and then closes. At the same time, the corresponding level of fluid is measured in the well, which is obtained at 132 m depth of the well. Then, using an air compressor, a pressure at the wellhead of 0.536 MPa is created. The pressure values indicated on the measuring head are recorded. At the scale determined by the pressure in the head of the well, the water level in the well is lowered. This lowering of the water surface is approximately 50 m.

Determining the volume of the corresponding cavity in accordance with the proposed method in this case is carried out in such a way that due to the opening of the half-turn valve, the air is released sharply and only for a short time. for pressure measurement. Part of the Exhausted air volume is compensated by replacing the water that entered the well through infiltration, while

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the hole is stabilized in comparison with the initial pressure at a value below it by 541 Pa.

The hydrostatic conditions do not change in the well in any way, since invariably a part of the exhaust air in the well is replaced by water pouring in from the surrounding layers. In this case, the determining pressure changes are recorded continuously. Based on the above, the cavern value obtained by calculation (using the known material balance ratios) is 2600 m,

Example 2: Oil is transported by a 6868.25 m long steel pipeline with an internal diameter of 95.4 mm and a wall thickness of 6.3 mm between the tank group provided for the oil field and high-precision measuring heads for measuring The pressures described in Example 1, with a small scale division, namely, from the entry point (at the location of the tank), at a distance of 1630, 3670 and 6860 m, and a half-turn crane are fixed.

For carrying out the method, a tank with a known volume (receiver) equal to 288 cm3 is fixed at the place of oil inlet in the pipeline. In the initial state, the pressure in the pipeline is first measured. Then, by opening the half-turn valve, the oil is dramatically released from the pipeline to the receiver (until it is completely filled). Due to the sudden release of oil, the oil pressure in the pipeline drops by 13.963 kPa. As a result of a decrease in pressure, the narrowing of the diameter of the pipeline can be defined as elastic deformation or the amount of shrinkage can be determined.

A pressure change is also recorded after the release of oil. Taking into account the known compressibility factor for oil 4, MPa, it was established that from, the total volume of the pipe, t, e, from 49.1 m, 38.5 m of the pipeline volume accounted for the section from the place of pipeline narrowing to the beginning of the pipeline. From these data, the distance to the narrowing of the pipeline can be calculated, which is equal to 5380 m.

5 Example 3, For a basement of an unknown volume, only limitedly (for example, using a door to be closed) connected to the day surface, its volume must be determined with the aim of laying a basement.

For The method of implementing the proposed method in the basement has a highly sensitive measuring head for measuring pressure. The air pressure is 0.101325 MPa. The increase in the volume of air in the basement space was made possible by a sharp explosion-like opening of a gas cylinder containing 0.078 m of nitrogen under a pressure of 0.65 MPa. Due to detonation in the basement space under investigation, the pressure was increased by 530 Pa, and then equalized with the air pressure in the surrounding space.

According to the proposed method, the air pressure in the basement before detonation is measured and then the pressure after detonation is also continuously measured and the pressure is recorded as a pressure change. Using this data, a flow volume of 950 m is calculated.

The proposed method allows to determine the volume of cavities of any volume and different morphology.

Formulas and inventions

Claims (2)

1, A method for determining the internal volume of cavities, in particular, underground cavities, such as voids, caverns, galleries and similar natural formations, based on a change in the volume of the medium, is filled with Q 5 0 50 five 0 826 measuring the pressure values before changing the volume of the medium and after, by which} determine the desired internal volume of the cavity, characterized in that, in order to improve the accuracy of determining the internal volume of the cavity, the change in the volume of the medium filling the investigated cavity , carried out by means of an explosive. by means of a half-turn crane, an increase or decrease in the volume of the medium, and the desired internal volume of the cavity is determined by the formula: V - -, UP where & V is the specified volume change the medium filling the cavity under investigation; C is the compressibility of the medium; DR is the differential pressure change of the medium filling the cavity under study until the medium reaches stationary conditions, 2. Method of pop, 1, characterized in that when using a liquid as a medium, a sharp decrease in the volume of the medium of the cavity under investigation is carried out by abrupt inlet of a part of the liquid filling the cavity into a container with a known volume. 3, the method according to claim 1, wherein the abrupt increase in the volume of the medium filling the test cavity connected to the surrounding atmosphere, for example, the basement, is carried out by abrupt inlet of the medium from the gas balloon. Editor N. Yatsola Compiled by I.Nazarkina Tehred M. Khodanich Proofreader S. Cherni Order 1649 Circulation 485 VNIIPI State Committee for Inventions and Discoveries at the State Committee on Science and Technology of the USSR 113035, Moscow, Zh-35, Raushsk nab. 4/5 Subscription