CN201156028Y - Pneumatic water head excitation device for drilling oscillating permeability coefficient test - Google Patents

Abstract

The utility model is a drilling oscillation type permeability coefficient value test pneumatic water head excitation device. It is equipped with a pressure display gauge in the well, a sealing port for cables, and an exhaust valve is installed on the air outlet pipe of the sealed cavity. Advantages: The cost of determining hydrogeological parameters is low. There is no need to install permanent monitoring wells. It eliminates the huge cost caused by drilling, disposal of drilling cuttings, construction of monitoring wells and the pollution of well washing water to the environment. Testing can be performed rapidly at different depths and locations in the aquifer to determine vertical and horizontal variations in K values. Discrete data of high quality permeability coefficients at different depths are obtained in mostly unconsolidated formations. Achieve the highest data quality. Provides high quality data with little or no noise in formations with high to medium K values. Permeability coefficients can be determined for highly permeable aquifers for which other methods are not applicable.

Description

Pneumatic water head excitation device for drilling oscillating permeability coefficient test

technical field

The utility model relates to a pneumatic water head excitation device used in a drilling oscillation type permeability coefficient value test system. It belongs to the technical field of instrument testing.

Background technique

The determination of hydraulic conductivity is the basis of groundwater resource evaluation, numerical simulation, development and utilization, environmental protection and scientific management, and is usually obtained through on-site pumping or pressure tests. The field pumping test is to use pumping equipment (such as measuring barrels, air compressors and water pumps) to generate a certain water level drawdown in the wellbore, and record the water level in the wellbore with time. Bouy formula, etc.) to calculate the permeability coefficient.

The pumping test lasts a long time, requires a lot of equipment and operators, is expensive, has strict requirements on the site and well holes, and easily pollutes the aquifer. In the field test, the measuring rope is often used to measure the dynamic water level, but the water level changes very fast in the initial stage of the test, and manual measurement will inevitably cause errors, thereby reducing the reliability of the calculation results. The pressure water test methods mainly include the single hole pressure water test method and the three-stage pressure water test method. These test methods evaluate the water permeability of the fractured rock mass by observing the amount of water injected under constant pressure conditions, and cannot directly calculate the hydrogeological parameters such as the permeability coefficient, and the information utilization rate is low. In order to change this situation, many scholars at home and abroad have successively proposed some parameter calculation formulas based on the steady flow theory, but the test section of the pressurized water test is short and the duration is short, and only in rare cases is the steady flow, so the obtained The permeability coefficient error is large. In addition, the pressure water test has high requirements on the site and equipment, and the operability is not strong.

Existing head excitation devices require the installation of permanent monitoring wells. This is caused by the huge cost of drilling, disposal of drilling cuttings, construction of monitoring wells, and environmental pollution of well washing water. Testing could not be performed rapidly at different depths and locations around the site, so vertical and horizontal variations in K values could not be determined. Discrete data of high-quality hydraulic conductivity at different depths are not available in most unconsolidated formations. The highest data quality is not achieved. In formations with high to medium K values, high quality data with little or no noise cannot be provided.

Contents of the invention

The purpose of this utility model is to overcome the existing defects of the prior art, and to propose a pneumatic hydraulic head excitation device for the drilling oscillation type permeability coefficient value test system, which can determine the high permeability aquifer that other methods are not suitable for. permeability coefficient.

The technical solution of the present invention: the structure is that a decompression valve and an air intake valve are installed on the air intake pipe, and the air outlet of the air intake valve is connected to a sealed cavity, and the sealed cavity is equipped with an internal pressure indicator and a cable sealing port. An exhaust valve is arranged on the air outlet pipe of the sealed cavity.

The utility model has the advantages of quickly measuring hydrogeological parameters, which can save a lot of time and money. Mainly manifested in: 1) There is no need to install a permanent monitoring well, which eliminates the huge costs brought by drilling, disposal of drilling cuttings, construction of monitoring wells and the pollution of well washing water to the environment. 2) The test can be performed rapidly at different depths and locations in the aquifer to determine the vertical and horizontal variation of the K value. 3) Discrete data of high-quality permeability coefficients at different depths can be obtained in most unconsolidated formations. 4) In formations with high K value to medium K value, it can provide high-quality data with low noise or no noise. 5) Only the cables and sensors are in contact with groundwater, requiring only minimal decontamination of the test equipment. 6) During the air pressure oscillation test, no water is added to the well or ground water is pumped out, so the disturbance to the aquifer is minimal and the data accuracy is high. 7) It can determine the permeability coefficient of highly permeable aquifers for which other methods are not applicable.

By stimulating the change of water head in the boreholes arranged in the aquifer, the change law of the water head with time is measured in real time, and the permeability coefficient in different aquifer media is calculated on site by using the principle of groundwater dynamics.

Description of drawings

Accompanying drawing 1 is the structural representation of the utility model

Detailed ways

Comparing with accompanying drawing 1, its structure is that air inlet pipe 1 is equipped with decompression valve 2, air inlet valve 3, and the air outlet of air inlet valve 3 is connected to sealing chamber, and the well pressure display gauge 5, cable line seal are housed on the sealing chamber. Mouth 6, exhaust valve 4 is housed on the outlet pipe of sealed cavity.

When working, the compressed air enters through the intake pipe 1, and the intake pressure is adjusted through the pressure reducing valve 2. When the pressure in the sealed cavity reaches the preset pressure value, the intake valve 3 is closed, and the exhaust valve 4 is opened at the same time to stimulate the change of the water head. The permeability coefficient is calculated from this head change.

The device uses a certain excitation method, such as extracting a certain amount of water instantaneously, injecting a certain amount of water instantaneously, inserting a certain volume of columnar objects into the water or lifting the water surface instantaneously, and using an air compressor to generate air pressure to generate a certain amount of water in the borehole. The pressure, etc., causes the water head in the borehole to oscillate, and the test system is used to record the pressure value corresponding to the change of the water head with time for the calculation of the permeability coefficient.

As the air pressure in the well increases, the water level drops until the water pressure "rises" equals the air pressure "falls". Once the water level stabilized, the release valve was quickly opened, instantly releasing the air pressure in the well. Thus, without splashing water, the water level returns to its original position, while the pressure sensor and data logger record the change and time of the water level. Pneumatic shock testing can provide very high quality data that is free from the "noise" or interference of water splashes that result from mechanical shock methods.

Claims (1)

1, boring oscillatory type infiltration coefficient value test vapour-pressure type head excitation apparatus is characterized in that being equipped with reduction valve, air intake valve on draft tube; Seal chamber is inserted in the gas outlet of air intake valve; Borehole pressure indicator gauge, cable seal are housed on the seal chamber; On the escape pipe of seal chamber drain tap is housed.

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