WORKOVER EXPENSE REDUCTION; TUBING PRESSURE TEST
While pressure testing your tubing seems like a simple task, there can actually be some strategy behind it. If you don't follow all of the steps in this procedure, you can miss some simple, but common failures. There is nothing worse than conducting a workover, and still not being able to get a solid pressure test, only to find a valve at surface leaking.
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Prior to calling a pressure truck
1. Close the tubing valve closest to the tubing, the flowline valve, and the casing valve on the flowing side.
2. Start the pump jack and attempt to pressure up the tubing to the presco setpoint.
3. If the tubing pressures up and holds, open the tubing valve and start the pumpjack again. Pressure up to the presco shutdown pressure & monitor the pressure to confirm if the flowline valve holds. (If the well will not pump up discuss your supervisor. Some options to proceed would be tapping the bottomhole pump or calling a pressure truck to test.)
4. Once you confirm the flowline valve holds pressure, open up the casing valve to see if the check valve holds pressure.
5. If you are able to confirm everything holds pressure at this stage, then the pump must have pressured up the tubing, meaning that all of your equipment below ground level is functioning properly. If you are missing production, then you will need to start troubleshooting everything downstream of the pumpjack (flowline, facilities, etc.)
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If you need to call a pressure truck to conduct a tubing pressure test, follow these steps:
1. Stop the pumpjack with the head down (bottom of stroke)
2. Rig in pressure truck and pressure test lines.
3. If the well is sour, it would be a good idea to spearhead the sweet pressure test fluid with H2S scavenger, as once you fill the tubing you will not be able to add it later. Another thing to be aware of is if you are expecting wax issues, you might want to use a solvent to spearhead.
4. Close the flowline valve closest to the tubing and fill the tubing. Pressure test to 3500 kPa and hold for 5 minutes. (you might have to depressure down the tubing a few times to de-gasify the fluid and get a solid test.)
Caution, watch the rodstring closely as you pressure up. A high rod part might start to lift the polish rod out of the stuffin box. If required, attach the rod clamp to the wellhead using a sling or chain.
5. If you fail to tag pressure, pump at least a tubing volume as the fluid level in the tubing might be very low to start.
6. If you are unable to maintain a solid pressure, record pressure drop and/or feed rate.
7. Double check to ensure all surface valves are holding pressure.
8. Once the pressure test has been conducted at the bottom of stroke, start the pumpjack and lift the head to the top of stroke. Repeat pressure test steps again.
10. Once entire pressure test sequence has been conducted, ensure all valves are open to allow the well to bleed down the flowline.
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