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Recommendations to reduce automatic gas gun maintenance

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At UPC Global, we not only sell our products for the optimization of oil wells through the artificial lift but we also give the training to learn how to use them.

For this reason, we wanted to provide you with a series of recommendations to reduce the maintenance of the automatic gas gun, equipment designed for use with instruments for acoustic measurements and fluid levels which consists of a gas unit and a microphone.

When the automatic gas gun is placed in the well, load the volume of the gas chamber at a pressure that exceeds the pressure of the well before opening the casing valve.


The automatic gas gun uses a solenoid with a small dart valve and a small hole. The dart valve releases gas from behind the ½ ” moving piston that allows gas to flow from the gun chamber to the well. This small moving part could become clogged and stop operating if sand or any solid are sucked from the well to the gun's gas chamber. Solids and sand could prevent proper sealing of the dart valve, and the gas could continuously leak from the gun into the well. This problem requires that the gun be disassembled, cleaned and armed again. The volume of the gas chamber must be loaded with a pressure that exceeds the pressure of the well with nitrogen or CO2 gas avoiding the entry of sand or solids from the well. Remember to load the gas chamber with a pressure that exceeds the pressure inside the well before opening the casing valve. This will close the gas valve and prevent sand and solids from being sucked into the gas gun chamber. Also, most gas wells contain water vapor. This water vapor could enter from the well and cause corrosion and rust that could contaminate the mechanism.


Protect the automatic gas gun against corrosion by coating the thread.


The thread on the automatic gas gun can be damaged or corroded. Protect the threads with a light layer of grease or oil and place a plastic wrap (thread guard). The pressure range of 2000 lpc should be reduced if there is corrosion or wear on the threads. A 2 ”11 ½ V steel corrosion protector with male to female adapter (microphone protector) is available to protect the thread of the gas gun and microphone. The microphone protector is supplied with the new automatic guns. This protector should be installed and replaced when necessary.

 

Clean the dart valve, if gas is constantly leaking from the bottom of the pressure gauge orifice.


If there is constant pressure leak in the hole under the pressure gauge, then probably the dart valve inside the solenoid assembly is not making a seal, allowing pressure leakage from the relief hole. The solution is to disassemble the solenoid and clean the dart valve assembly. Use the wrench to remove the screws and use the solenoid to remove the spring from the solenoid. When removing the piston, be careful not to drop the piston spring or the dart valve and the piston. The dart valve is a small plastic needle inside the piston. You should visually examine the nozzle of the dart valve to remove any solid particles. Any obstruction can prevent the dart valve from making a proper gas seal on the valve seat. Only a grain of sand, a small metal filing, or any other solid particle can lodge between the dart valve and the seat avoiding airtight seal. The particles could allow pressurized gas to leak past the dart valve and discharge out. To clean the dart valve, clean the nozzle with a clean, soft cloth or if it is in the field the fingers may be sufficient. After cleaning the dart valve, reassemble the solenoid. If the dart valve nozzle is damaged, then it must be replaced. The dart valve can be removed from the piston. Then replace it with a new valve and reassemble the solenoid. If after cleaning the dart valve the gun continues to leak below the small gas relief hole of the pressure gauge, then the dart valve seat should be inspected. The dart valve seat is located just below the valve piston assembly and remains in place with an o-ring. The seat can be removed and there could be solid particles lodged inside the seat. Spray with a contact cleaner through the hole of the dart valve and through the two slots on each side of the valve seat. The sprayer should eject out any particles and clean the hole. The o-ring of the dart valve seat must be free of cuts and abrasion. After the seat is inspected, replace and lubricate the o-ring of the valve seat. Then assemble the solenoid and adjust with the spanner.


Replace the O-ring in the gas valve, if there is gas leaking from the gun base.


A symptom from which gas under pressure is expelled when the gas valve is passed and filtered out at the base of the gun, leaking into the well, is shown by the pressure gauge by not accumulating the pressure or maintaining positive pressures. The problem is mainly caused by the smaller of the two o-rings (WG-1700) in the gas valve. The reduction in the o-ring allows the passage of pressurized gas into the well. The solution to repairing this problem is to remove the gas valve and replace the o-ring. To disassemble the gas gun:

o Remove the chamber to expose the hole and the hole housing.

o Remove the hole housing with a 7/8 ”wrench.

o Use the 6-32 repair kit to screw on the gas valve stop.

o Pull the gas valve from the housing. Inspect the small o-ring at the bottom of the gas valve for cuts or deformations.

The smaller of the two o-rings does most of the work and produces the seal because it fits into the hole in the lower part of the housing and closes the chamber. The gas valve is continuously working as the gun is fired, so the small o-ring suffers a lot of wear and tear. When the gas valve is removed, then a lubricant or grease should be applied to the o-ring. The lubricant helps the gas valve slide more freely and increases the life of the o-ring. Inspect the WG-1600 o-ring at the bottom of the hole housing and replace it if it is cut or worn. Failures in the WG-1600 o-ring could prevent proper operation of the orifice, allowing pressurized gas to leak through the orifice and leak below the orifice housing inside the gas valve chamber. This type of leakage prevents the pressurized gas from being diverted from the top of the gas valve fast enough for the gun to function properly.


Clean the hole and the hole housing if they become clogged.


The hole (WG-1500) has a hole of 0.015 in from the center and is screwed into the housing (WG1550). The hole and its housing need to be cleaned if they are clogged with solid particles that restrict the flow of pressurized gas into the chamber volume. The hole and its housing are cleaned first by removing them from the gun, then spray them with WD 40 or a pressurized electric contact cleaner. The hole is removable and can be replaced by a new one, however, it is normally reliable and trouble-free.


Lubricate O-rings on the mobile gas valve.


Put some lubricant inside the gun. Make sure the chamber inside the gun is clean when the valve is operating. An accumulation of debris or solid particles within the chamber volume can prevent the gas valve from moving freely which is necessary for it to operate properly. Do not wait for long periods between each maintenance of the gas valve. The remote firing gun must be disassembled, cleaned and the O-rings relubricated. Lack of proper maintenance will allow Orings to dry out and friction can block the gas valve inside the gun. The Orings have so much friction that if they dry, they can block the gas valve preventing the remote firing gun from hitting. If excessive pressure is required to hit the remote firing gun, it is probably necessary to lubricate the gas valve. If a pressure restoration test is going to be performed in a well, the recommended practice is to inspect both the dart valve and the gas valve before starting the test.


Do not fill the gas gun with liquid CO2.


Occasionally, the bug inside the filling connector may remain open and drain CO2 gas out of the volume chamber into the atmosphere. Gas leakage is caused by the freezing of CO2, while it is discharged into the volume chamber of the gas gun. Filling the gun with gas instead of liquid CO2 prevents the freezing of the bug. When the 7.5 oz CO2 bottle is used, the bottle stop must be above the bottom of the bottle so that the gas above it is discharged instead of liquid CO2 from the bottom of the bottle. If the gas gun is filled with the 7.5-ounce bottle placed directly on the gas gun, the liquid CO2 in the 7.5-ounce bottle may freeze when entering the gas gun and cause a leak in the connector filling the gas gun when the 7.5 oz bottle is removed from the gun connector.

Keep the filling connector housing free of debris.

If residues in the worm inside the filling connector cause a leak in the gas gun, lubricate the inside of the valve with light oil. Remove the fill connector and place the oil directly in the center of the valve. Install the bug and then fill and discharge the gas gun with CO2 several times. Shooting the gun several times will remove debris from the center of the valve. Be sure to properly adjust the bug when removing the connector.


Replace the fill connector housing when the fill tube is damaged.


When the 7.5-ounce bottle is used to fill the remote gas gun, occasionally, the 7.5-ounce bottle may be repelled from the connector due to the pressure exerted by the gas when exiting the bottle by forcing the connector out of Your accommodation A worn, folded or flattened fill tube in the fill connector prevents CO2 from being released into the volume chamber of the gas gun. The solution is to replace the filling connector housing.


The internal cable of the BNC microphone connector of the remote gas gun can break. Pulling the BNC microphone connector too far from the housing may break the internal cable.


If the coaxial cable is entangled to the BNC microphone connector, do not pull it to release it. Be sure to use a 90-degree BNC “L” electrical connector with the remote firing gun to protect the BNC connector on the gas gun. When connecting and removing the BNC connector or the 90 degrees BNC “L” electrical connector, be careful. These connections must be kept clean all the time.

 

When changing the fill connector from an empty bottle to a full bottle, remove the fill connector from the empty bottle and wait 5 minutes for the expanded O-ring to reduce its size.


Generally, the fill connector of a 7.5 oz bottle is removed when the bottle is empty and the fill connector is placed in a full CO2 bottle to continue testing wells. When you remove the fill connector, the purple O-ring in the fill connector expands. When the filled connector with the expanded Oring is placed in a 7.5 oz. Bottle of CO2, the expanded O-ring is generally damaged by placing the filling connector in a new bottle causing CO2 leakage from the bottle. To change the fill connector from an empty 7.5 oz. Bottle of CO2 to a 7.5 oz. Bottle of full CO2, remove the fill connector from the empty bottle and wait 5 minutes to allow the expanded O-ring to recover its size, lubricate the O-ring with a few drops of oil and install it in the 7.5 oz bottle of full CO2.


The microphone cannot be repaired in the field, do not disassemble it. If fluids enter the microphone, it will be damaged.


Saltwater will cause immediate failure of the microphone if its entry into the microphone is allowed. Clean the lower threaded portion of the remote firing gun after each day of use with a mild cleanser such as soapy water, alcohol, WD 40 or an electric contact cleaner that can be obtained at an electrical supplement store. Then, cover the inside of the lower chamber of the remote gun with grease or a thin layer of oil. If the microphone is removed from the remote firing gun, be sure to clean the lower portion of the gun and also the microphone before proceeding to reinstall the microphone in the lower chamber. If the microphone is removed from the remote firing gun, always replace the O-ring with a new O-ring that fits the electrical connection between the microphone and the remote firing gun. Be sure to lubricate the O-ring with an O-ring lubricant, grease or oil.


When wells are chemically treated on the surface, the Echometer gas gun must be cleaned at the end of each day.


The gun and microphone are made of stainless steel and the microphone has layers of mylar plastic. Almost no hydrocarbon oil or water will damage the microphone. Some wells are chemically treated by surface corrosion. High concentrations of some chemicals are corrosive and will cause corrosion to the stainless steel parts of the Echometer gun. If the wells that will be acoustically tested are chemically treated on the surface, the Echometer gas gun must be cleaned at the end of each day because the chemicals can be corrosive to the parts of the gas gun. Then use a hydrocarbon solvent, soapy water, alcohol or a household cleaning agent to clean the portion of the gas gun exposed to gas from the well. Let the parts dry or dry them with compressed gas.

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