(1) The motor tail monitoring device (ie PHD, PSI) measures pressure;
(2) Type III pressure measuring valve
(3) The dynamic liquid surface is converted to pressure method for pressure measurement.
The PHD or PSI manometry is currently in the experimental phase and is used less in production due to its short life. Due to the influence of the foam section of the casing ring space, the calculated pressure value error is large and the scope of use is limited. Type III pressure measuring valve is a commonly used pressure measuring method. It is used together with mechanical pressure gauge to measure the static pressure and flow pressure data of submersible electric pump wells. Use the plugging device instead of the drain valve.
1. Structure and working principle of type III pressure measuring valve
The Type III pressure test valve consists of a working cylinder, a plug, a connector and a salvage. The occluder is installed in the working cylinder down to the downhole, and the pressure detecting valve is closed by the sealing action of the inner and outer packings, and if necessary, the fishing device can be used to remove the pressure detecting valve from the working cylinder. During pressure measurement, the connector is docked with the test rod of the plug at the lower end of the pressure gauge, the spring is compressed by the weight of the instrument, and the test rod is positioned by the internal contact of the connector and the spring. The Ï†6mm horizontal hole at the upper end of the test rod is connected with the horizontal hole on the side of the connector mating body. At this time, the oil pipe is connected with the casing, the pressure is along the Ï†6mm hole of the working cylinder, the Ï†4mm hole on the plug body, and the Ï†6mm horizontal through hole at the lower end of the test rod. , enter the center hole of the test rod, and pass through the Ï†6mm transverse through hole at the upper end of the test rod, and transmit it to the annular space of the connector mating body and the outer mating part, and enter the pressure gauge through the upper joint. After the pressure is measured, the gravity disappears and the test rod is automatically reset by the spring to close the pressure measuring valve.
2. Safety inspection and preparation before pressure measurement
Check the firmness and reliability of the anti-nozzle, mast, and rope, the sensitivity of the pulley; check the accuracy of the revolution table, the integrity of the winch and the wire. Check that the wellhead equipment has no leakage and the gate switch should be flexible. Understand and master the column structure of the pump shaft to be tested, the type and accuracy of the pressure valve and the ground flow of the well.
Master the production dynamics, liquid production, oil pressure, casing pressure, water content and pressure before the electric pump well pressure measurement. If the waxing of the electric pump well to be tested is serious, it should be contacted with the oil production team in advance to clear the wax first and then measure the pressure to ensure that the pressure gauge starts smoothly. Record the parameters of the electric pump well before the pressure measurement, in order to compare with the data admitted after the pressure measurement.
3. On-site pressure measurement safety technology
(1) Prepare one of the mechanical pressure gauge and the pressure measuring clock, one 0.5m long weighting rod and one rope cap, and the test tool.
(2) Check the interference of the connector packing with a Ï†18mm mast and use the adjusting nut to achieve the interference.
(3) Connect the weighting rod, pressure gauge (without shock absorber), and connector from the rope cap in order.
(4) Open the anti-nozzle plug, put the installed pressure measuring instrument, open the wax gate, proofread the number of tables, use the winch to send the pressure gauge into the well, pay attention to the speed of the release should not be too fast, to 0.8m / s is appropriate to avoid twisting the wire.
(5) When the pressure gauge is below 5~10m above the working cylinder of the pressure measuring valve, stop the flow pressure of the oil measuring pipe for 5min first, then continue to lower it (the speed remains stable, not too fast, preferably 0.5m/s) . After stopping the manpower cylinder for 5 to 10 minutes, the measured pressure is the casing flow pressure. In order to ensure the success rate of the test, it is generally required to repeat the test more than 3 times. Finally, lift 100m for 5min and measure the pressure gradient of the tubing.
(6) After the measurement result, the pressure measuring instrument is mentioned to the wellhead, the wax gate is closed and emptied, the instrument is taken out and the pressure measuring card is checked.
5. Safety Precautions
(1) When the CY-613 pressure gauge is used for pressure measurement, the shock absorber can be omitted, because the buffer spring is already installed in the connector to prevent shock. In addition, after the shock absorber is removed, the reaction force of the spring is reduced, and the test success rate can be guaranteed.
(2) The speed of the downhole instrument should be properly mastered. When the instrument is seated and lifted, special attention should be paid to it. The speed should not be too fast, because the speed of the next person is too fast or mammoth, not only will damage the pressure gauge, but also cause measurement. The violent shaking of the card causes the curve pattern to be distorted and unclear, leading to misjudgment. When the pressure is too fast, it will cause impact on the anti-nozzle, the accident of breaking the wire, the falling of the well, and in serious cases will cause harm to the personal safety of the wellhead operator. Therefore, when the test instrument is required to be lifted 30m from the wellhead, the instrument should be taken out by hand to win the instrument to ensure the safety of the test instrument and the human body.
(3) Before the downhole is re-inspected, the packing of the connector should be inspected in detail according to the requirements of the regulations. The damage and undesired must be changed to ensure the sealing performance of the packing.
(4) After each pressure measurement, the pump and oil should be tested to check whether the pump efficiency and displacement are normal.
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