Q Q: 506615608
Well washing is a key process of well completion technology. In engineering construction, geothermal wells usually have to go through simple or complex well flushing technology, and use a variety of well flushing methods. Under special circumstances, a well washing method is repeatedly used to make the water quantity and temperature of geothermal well meet the requirements of design or contract indicators, and try to achieve the best water quantity and temperature at the same time. The quality of the project is qualified. After pumping test and water sample test, it passes the water quantity and water quality inspection.
Compressed air well flushing is a common method, which requires air compressor to provide compressed air (positive and negative circulation), vibrate and pump internal flushing fluid, dredge cracks and remove sediment.
There are two kinds of air compressor well washing devices, parallel type and concentric type, which can be selected according to the actual situation. With the help of the air pressure of the air compressor, the water level in the hole oscillates, the well pipe is impacted, the mud skin is damaged, and the sediment at the bottom of the hole is discharged from the ground. Air compressor well flushing is one of the common well flushing methods. In general, the effect of well flushing is better.
Water pump and air compressor well flushing. In the drilling with larger and deeper hole diameter, this kind of combined well washing method is often used, that is, the drill pipe is lowered near the mud sediment, the sediment is washed to a certain height with the help of water pump, and then the sediment is discharged from the ground with the help of air compressor. This method has a good effect for the well with deep aquifer and more mud sediment. For example, in the area of water shortage in Jianghuai red bed, the formation is purple red clay rock, which collapses seriously, so mud drilling is used. Because the hole is deep and the drilling time is long, the mud pastes the wellbore. In this way, we use this method.
The application of compressed air technology in geothermal well flushing is mainly applied to geothermal well flushing with compressed air, which is commonly used as high-pressure and high displacement air compressor in petroleum drilling industry. Generally, the capacity of air compressor is 10 cubic meters and 150 kilograms. The back flushing method is adopted, and the air pipe is made of drill pipe, and the running depth is generally 500-1km. The method of producing intermittent jet by compressed air well flushing (continuous jet when the amount of water is large) can reach several meters.
The well washing machine is composed of air pipe and water outlet pipe, and is installed in parallel. When the compressed air reaches a certain depth of the outlet pipe through the air duct, it mixes with the liquid in the outlet pipe and forms a negative pressure in the outlet pipe, which makes the liquid in the outlet pipe move upward. The mud, sand and rock cuttings in the lower part immediately enter the outlet pipe and form a three-phase mixture of gas, liquid and solid, which is discharged out of the well together. The mechanism of well flushing is similar to that of positive circulation.
In the same well, the free suspension velocity of cuttings with the same diameter is different due to different well washing methods (different upward return channels of well washing fluid). When using the same air compressor to wash the well, the cuttings discharge capacity of reverse circulation is stronger than that of positive circulation, and the cuttings discharged are larger than that of positive circulation.
The fluctuation amplitude of water column in the well can reach several hundred meters, and the instantaneous release of water column pressure of several hundred meters is helpful to dredge the aquifer. According to the ratio of the duration of water production to the interruption time, the water production capacity of geothermal wells can be estimated. After the completion of compressed air well flushing, the water pump is generally used for well flushing test.
A four stage pressurized high pressure air compressor with a flow rate of 10 cubic meters per minute and a very high pressure of 25 MPA can push a water column more than 2000 meters deep out of the ground. The negative pressure in the well instantly forms, which makes the water in the formation wash out naturally and effectively improves the well washing speed.
Well washing is a flexible use of air compressor, and also an important embodiment of air compressor in construction industry.