Transmitter and Sensor

Function or application of wellhead control panel

2011-07-27T17:02:00.000-07:00

Gas wells and oil wells has a high potential hazard, either because the material ejected flammable nor the potential hazard of the gas pressure is high. Making oil well or gas well in X-mastree (well his head) are always installed valve. Its function is to shut down the well in case conditions that harm or for other interventions as well as the work test, etc.
Here I will only discuss WHCP from gas wells, as I understand. Function or application WHCP depending of each type of wellhead control panel. There is a simple, until there is a tricky. If it can be inferred is actually a function of well head control panel is to operate well, be it for shut in and POP (put on production). With the wellhead control panel we able to open or closed the DHSV via the push button contained in panel. Also we can also open or close a master valve or wing valve with button push button as well. It was all done manually, by pressing or pulling a button push button. But to close the DHSV, Master valve, Wing Valve can be done automatically, namely through the integration with shutdown system from the well. Surely this should follow the philosophy of the shutdown system used by each company .

By looking at the picture, then it will give an overview of what functionality or usability of the wellhead control panel. The components iare visible in the picture can be grouped into:
All of these components will give feedback or as a input signal to the Wellhead control panel (WHCP). While in the well itself (flowline) there is a sensor that is used to monitor the condition of the well, either to shutdown the system, or just for readability only. Instrumentation for shutdown system e.g.:

PALL (pressure switch low low)
PAHH (pressure switch high high)
The Fusible plug (for detection of fires), usually mounted above fangles, or parts that there is a possibility of leaks (the source of fire)

The instrumentation used for reading, for example:

FR (flow recorder)
PR (pressure recorder)
TR (temperature recorder)

The Final element of the system shutdown:

DHSV, Down hole Safety valve ( drived by hydraulic power)
MV, master valve (drived by hydraulic power)
SSV, surface safety valve (drived by pneumatic power)
Choke valve, manually operated
SDV (shutdown valve) installed in flow line of well, outside the part of the wellhead (X-mastree)

Valves are a part of which will receive command of the signal to be opened or closed from Wellhead control panel. So if I can give analogical WHCP is a controller (within the science control system), SSV, MV, DHSV, SDV are the part that receives the output from the controller, while the PALL, PAHH, fusible plug is the input of the controller. But don't imagine WHCP like PLC in General. WHCP I discuss here is that it uses control pneumatic or hydraulic. Why WHCP generally use pneumatic control, because most of the well gas wells far location (remote) so hard to find sources of energy such as electricity. And generally WHCP from gas wells using gas from the well itself as a source of pneumatic power. Later will be discussed where the pneumatic power source to run the WHCP. With pneumatic power from gas, we can also have hydraulic power, i.e. by install the hydraulic pump on run by pneumatic power. Hydraulic power is used to run valve actuator which relatively large power needs. Pneumatic-powered convert hydraulic power can become larger. By using the pump.

The Problems That Often Arise in Wellhead Control Panel (WHCP)

2011-07-27T08:36:00.000-07:00

From the various experiences, I encountered problems that often arise in WHCP are leaking, popping, and stuck. Commonly Leaking occurred in the connection of nuts on tubing. It could be leaking at a three way valve components. To this we can issue leaked retighten the bolts or given a Teflon sealant. If for three way valve usually I replace the internal parts like its o ring, whereas in order to overcome stuck at three way valve I do greasing of internal plunger. Stuck in a 3 way valve because it is dirty or arid.

For ordinary problems popping occurs at PSV. PSV is safety equipment to handle excess pressure. Each panel of a pneumatic or hydraulic there must have been his PSV. Just like in the WHCP. When there is an excess pressure, PSV will popping, to release the excess pressure. When it was popping PSV unbiased back to its normal position, the problem is often the case. To fix this we clean the inside and then check the setting.

One of the disadvantages of pneumatic systems which use hydrocarbon gas as a source of power instrument is if the liquid into a pneumatic system. This will cause three-way valve not working well. If the wrong selection of the material, example the Oring not resistant with hydrocarbon substances, will certainly damage the o ring itself

Discussion of Wellhead Control Panel (WHCP)

2011-07-27T08:33:00.000-07:00

When we work on the world oil and gas industry, the term wellhead control panel are familiar. The Operator well, Instrument technician, Well service maintenance, Well service operators are part of the work that is always associated with a well head control panel nor the well itself, be it for gas well or an oil well. The level of complexity of each well head control panel vary, each company has its own standard. So the definition of well head control panel in General will certainly vary, the definition of well head control panel if we review of its functionality is part of the surface facilities of the gas well or an oil well that is used to control well, like: be it to shutdown system, the casing pressure reading parameters, tubing pressure reading parameters, temperature well parameters. So to open or close a Wing Valve (WV), Master Valve (MV), as well as Down Hole Safety Valve (DHSV) can be through the Wellhead control panel. Generally inside wellhead control panel consists of control pneumatic or hydraulic.

Control pneumatic or hydraulic composed of tubing and three way valve. When we studied the wellhead control panel, then we will be required to learn more the components of control pneumatic or hydraulic. Location of the position of the well head control panel there is usually near the well its selft.

Calibration accelerometer 86517 Bently Nevada

2011-05-26T05:02:00.000-07:00

How to calibrate Accelerometer 86517 Bently Nevada,
To perform these procedures, Firstly prepare the following tools:

Function Generator (50 ohm output)
DC power supply -24 Vdc
Multimeter
Small screw driver
Capacitor 0.01 microfarad 1% capacitor, (BNC conector P/N 00448308)

Step to calibrate:

Connect power supply to the - 24 Vdc and COM terminals on the accelerometer, and adjust the output of power supply to -24Vdc, connect multimeter to the +ACCEL terminal, connect capacitor 0.01 microfarad to function generator, the input should connect to terminal C and leave pins A and B not connected. Don't forged to connect the interface module case to common through the case sheild terminal. Make sure the interface module case is netral
Adjust the function generator to null output level and measure the acceleration signal with the multimeter, if the reading is more than a few milivolts rms then setup is probably injecting power line noise into the charge amplifier, this noise must be eliminated, reduce lead lengths and changing lead routing
Adjust the function generator output to 0.3535 Vrms sine wave at 100 Hz for a transducer sensitivity of 50 pC/g, or 0.707 Vrms for tranducer sensitivity of 100pC/g
Measure the acceleration output with the multimeter. If the output reads 0.3535+/-7.0 mV rms go to step 8, If the output does not read 0.3535 V rms +/- 7.0 mV rms continue with step 5
Unscrew the four screws at each corner of the lid
Open the lid and fold it back
Adjust the potentiometer until the multimeter reads 0.3535 +/- 7.0 V rms, close and tighten the lid and verify thet the multimeter still reads 0.3535 V rms, if it does not repeat step 6 and 7, be aware when the lid is open the circuit is unshielded and the charge amp can pick up noise.
Disconnect the input from pin C and connect it to pin A and leave pin C and B unconnected, verify that the multimeter still reads 0.3535 Vrms +/- 7.0 mVrms. If it does not then check your test setup as step 2 and repeat this step. If the test is not passed, replace the interface module.

Manual Book ACCELEROMETER 86517 Bently Nevada will be posting next...
(reff: http://www.sensortransducer.com)

Calibration Gas Detector BW Killark Gas Point

2011-05-25T08:36:00.000-07:00

Calibration of BW Gas Point can be executed at any time during normal operation except the selft tes period (from 10 minutes before the selft test until the selft test is complete) BW technologies recomends a premium grade calibration gas, Gases with NIST (National Institute of standards and Technology)

Start Calibration:

1. Press and hold the external button down while the LCD displays the alarm setpoints, continue to hold the button until the display reads CAL (approx 5 seconds) and then release the button.

- The 4-20 mA output will be 3 mA throughout calibration. Calibration the Gas Point will not cause false alarms at the controller

- on this step: first LCD monitor will display low and high alarm (approx 8 sec), next the CAL icon lights for 3 sec, gas type is constantly displayed and backlight is activated.

Auto Zero

2. The Gas Point will then take a zero level reading, combustible and toxid sensors; if background gas is present, apply zero the sensor, restart the calibration sequence will take 30 to 60 seconds.

- On display, numeric display will read 00, auto zero advice flashes, gas monitor constantly displayed.

Auto Span

3. Insert cal cap and apply gas to sensor for approx 2 minutes (ammonia 5 minutes)

4. When the countdown (300 to 00) begins, spen is complete, disconnect the gas

- If span fails: check calibration gas cylinder used and concentration expected. Replace the cylinder and/or change the cal gas expected value, if required, recalibrate

- Oxygen sensor, use pure air calibration gas (20.9% O2) in case of deficient to enriched atmosphere.

- on display : numeric display will show calibration gas value expected, gas cylinder icon flashes, span advice lights, gas type is constantly displayed, after a succesful calibration, gas point automatically returns to normal operation and displays the current reading (ppm or %) present

Faults code on Gas Detector SC111/112 General Monitors

2011-05-25T05:49:00.000-07:00

During work in field sometime we find some problem with the gas detectors, so we have to know that faults code.

F1= Fail to zero

This fault may occur during calibration for either of the following reason:
- faulty sensor : the sensor will need replacement
- Gas present : If the magnet was applied with a high level of gas present, the SC111 will not be able to obtain 'Zero' it indicates this by displaying 'F1', so ensure sensor is in clean air.

F2 = Fail to calibrate

Latches until magnet is placed over the general monitors logo, this fault will occur if the unit is put into calibration mode or calibration check mode, but no gas has been detected within 3-6 minutes.

F3 = Fail to Span

Latches until magnet is placed over the general monitors logo, this fault may occur during calibration:
Low gas : If the gas concentration applied to the unit does not give sufficient response for a valid 'SPAN' <use the correct gas concentration>
High gas : If the gas tester applied to the unit would give a perceived overflow condition. <use correct gas concentration>
Bad sensor : If the sensor response has gone bellow an acceptable level <replace sensor>

F4 = Sensor Passive bead open circuit

Latches until power down, this fault occurs when: the sensor passive bead becomes open circuit or the sensor black and red leads become disconnected < check black and red wires or replace sensor as appropriate.

F5 = Sensor active bead open circuit

latches until power down, this fault because the sensor active bead or white lead goes open circuit. < check white lead or replace sensor as appropriate.

F6 = Power Low

This fault because the supply voltage between the brown and blue leads drops below 15Vdc approximately < ensure that supply is at least 20 V dc> note: maximum resistance per lead is 10 ohms for a 24 Vdc or 5 ohms for a 20 Vdc.

F7 = EEPROM fails to verify

This fault occur during calibration when an attempt to verify the calibration parameters just written to non-volatile memory fails.<place the magnet over the General Monitors logo and the unit will attempt another EEPROM write and verify>

F8 = Negative Sensor Drift

If negative sensor drift is greater than 5% but less than 10% FSD, then 'F8' is displayed and the analogue output goes to 3 mA, however if negative sensor drift is greater than 10% FSD then the analogue output goes to 0 mA and display continues to read 'F8'. This fault condition has a timeout of approximately one minute before the display and analogue output exhibit any change in status, and this condition does not latch

Calibration Check on SC111/112 General Monitors

2011-05-25T05:03:00.000-07:00

After perform calibration on Gas detector SC111/112 then will continue to perform calibration check:

Position the magnet over the General Monitors logo, The symbol '--' will be displayed for three second and then will begin to flash
Remove the magnet and the display will now flash the gas concentration at the sensor. The analog output will be held at 1.5mA regardless of the gas concentration at the sensor.
If gas is not applied within 6 minutes the analog output will fall to 0mA and the display will read 'F2'. To recover from this position, replace the magnet over the General Monitors Logo, repeat step 1 and 2 then proceed to step 4 within the timeout period
Apply gas at 50% LEL to the sensor. Observe that the gas reading settles at 50+/-5%. Should the final response fall outside this limit, a full calibration is required. Note : The sensor should be exposed to clean air conditions for at least two minutes prior to entering calibration mode.
The display will continued to flash and the analogue output will remain at 1.5mA until the gas has been removed and the level at the sensor drops below 3% LEL approx. Normal monitoring will then be resumed (i.e the display will give a steady reading and the analogue output will follow the gas concentration at the sensor)

Calibration Gas Detector SC111/112 General Monitors

2011-05-25T04:45:00.000-07:00

When Gas detector Model SC111/112 General Monitors power-up, it will take an initial power-up period of 1 minute approximately, and is observed by the SC111 during which it display "PU". This is to allow the sensor to stabilize, then the display should read '0' if there is no gas present at the sensor. If doesn't occur then refer to manual book, in section troubleshoot.
Calibration SC111/112 General Monitors:

Ensure that the SC111 has stabilized for at least 1 hour, and there is no combustible gas present at the sensor. A true zero reading will be obtained when the reading stabilized at the lower value.
Place the magnet over the General Monitors logo at the surface body. '--' will appear on the display first to indicate that the magnet has been positioned correctly. Then the display will begin to flash. After a total of 9 second 'AC' will be displayed, indicating that the unit is in the auto-calibration, then remove the magnet.
Use a General Monitors Portable Purge or Calibration Chamber to apply gas at 50% LEL (+/-5%) to the sensor. When the SC111 detects this gas it will display 'CP' , this mean 'CP' = CALIBRATION IN PROGRESS
Wait until 'CC' is displayed before removing gas. This will normally take less than 2 minutes, 'CC' = CALIBRATION COMPLETE
When the gas disperses from the sensor the SC111 will leave CALIBRATION MODE and return to a normal monitoring condition. The display should read '0' when the gas has dispersed.
If the above does not occur as describe and a different code is displayed..go to the TROUBLESHOOTING section

Barton Model 202E Differential Pressure Recorder

2011-05-24T22:04:00.000-07:00

The Barton Model 202E single DP Flow Recorders measure and record system operation parameters including gas and liquid level in a vessel, and other system variables that can be measured by differential pressure and static pressure methods.
The main components of Barton Model 202E are:

Differential Pressure Unit

This part Differential Pressure Unit (DPU) actuates the recorders, the DPU is a dual bellows assembly enclosed within pressure housings.

Adjusting Pulsation Dampener

This part of DPU

Recording Mechanism

This part as a linkage and pen system that permanently records data. It converts mechanical inputs from the DPU and static pressure element to transcribe lines on revolving chart. All material parts of the recorder mechanism are made of stainless steel.

Static Pressure Element

This element measure static pressure in a piping system from 0 to 30 inches of Hg vacuum or from 0 to 10,000 psi. The sensor element is a bourdon tube consisting of a slightly flattened cross-section of tubing coiled into a helix or flat spiral. The outer end of the tubing is seald and attached to a drive arm, which is attached to the static pressure connection tubing.
Generally, Barton recorder require no maintenance other than replacement of the chart, replenishment of the ink, winding of the spring-wound chart drives, and occasional calibration. In addition, the operator should periodically check the door seal for wear and the pressure fittings for tightness:

Differential Pressure Pen Calibration

- Make sure chart plate is on same plane and flush with hub flange, the chart must be flat with the hub locked. Also, make sure the pens and pens arms are correctly connected and that they do not interfere with one another.
- With a chart locked into place, move the pen from zero to full span and back to ensure that the pen travels along the time line. If adjustment are needed, loosen the two pen mount screws, adjust the pen mount position until the pen follows the time line, then tighten the pen mount screws
- Disconnect the differential pressure drive link from the range arm. Move both differential and static pressure pens to full span. Adjust the static pen so that pen around 7-15 minutes apart by adjusting the static pen arm mounting location on the pen arm shaft assembly. Move both pens to the 50% indicating position. Ensure that the pens don't interfere with one another. Adjust static pens as necessary, don't alter the differential pressure pen once it has been adjusted to the time line
- Ensure that there is enough pen pressure against the chart to produce a continuous line. If necessary, adjust the pen pressure by bending the arm in the required direction.
- Unlock the flow recorder hub clip. Remove the chart and chart plate
- Mount a calibration chart into the flow recorder hub. Lock the chart in place. Move over range stops out of play
- Apply 50% differential pressure to the high-pressure side. Arrange the differential pressure linkage. Set a 90 deg angle between the drive arm and link. By varying the length of the link, set a 90 deg angle between the range arm and link. Slip the range arm to 50% on the chart
- Remove the pressure, the pen should indicate zero. if the pen deviates less than 10% from zero in either direction, perform fine adjustment by using the pen zero adjust screw and proceed to step b. if the pen deviates more than 10% from zero, make adjustment as follows:
a. Rotate pen arm and shaft by gripping the range arm and forcing (or slipping) the pen until it indicates zero. The pen arm and shaft should rotate at the range arm pivot point without loosening the range arm lock screw.
b. Apply 100% pressure, Make necessary adjustment by turning the range arm adjust screw counterclockwise if the pen is slightly under ranged and clockwise if the pen is slightly over ranged. Repeat zero and 100% adjustment until calibration at these points is achieved.
c. Apply 50% pressure, the pen should be on the 50% chart line. If the pen is to low, lengthen the linkage to make a correction 40 times as great in the high direction. adjust the pen to 50% as in step a, ensure all linkage screw are retightened.
- Repeat step 8 until calibration of all three points (0,50, and 100% indication) is achieved. To assure accuracy, a nine-point calibration check ( 1, 25,50,75 and 100% ascending and descending) must be run

Manual Book Barton Model 202E NUFLO, will be posting next...