A major operator, in the Ukraine, contracted to do an application on a poorly performing well (best production 12BOPD)and flowline to see if FloWell could assist in controlling the wax problems which often caused intervention by having to dismantle and clean the flowline which was passing through valuable agricultural land through a 2Km flowline. This flowline led to a test separator and then onward to a processing facility.
Prior to the application the well production failed and oil production stopped. A Gas-lift system was used to recover oil from this well and for over the last few weeks the well showed no signs of recovery.
Gas was coming back dry. So regardless of zero production it was decided to use FWTO (FloWell Treated Oil) to see if it could clean the Flowline to the separator only. This was the original mandate.
So, the task was set to the FloWell team: Clean wax from the flowline.
The application required the FWTO to be injected down the annulus of the well and then using the gas-lift process to force the material through the well pipeline and onto the separator via the Flowline.
Unfortunately, possibly due to an overzealousness or faulty gauges the planned operation was completed in 40 minutes instead of the 1.5 hours proposed (It is extremely cold (-15°C) and the pump operator maybe wanted to suffer as short a time as possible).
Wax build-up was usually monitored by checking the differential pressure between the WHP and the Separator pressure. After about 8 hours from the application the separator pressure dropped to zero indicating a blockage.
Our applications engineer assumed that the application was a failure and the site engineers continued compressing the annulus waiting on gas to U-Tube with the tubing.
After certain time taken to compress the annulus FWTO was kicked out of the tubing, flowing through flowlines to the separators. But as test separator could not measure flowrates and it was decided to stop.
On opening of separator, they were astonished to find it was completely blocked with wax and other contaminants including ice. They then proceeded to clean the separator which took many hours until all the contaminants were removed.
Once finished they reopened the flowline but as it was extremely late closed down for the night. A total of over 5m3 of contaminants were removed and the total volume of the flowline is approximately 9m3 so it was assumed that all contaminants were removed from the flowline.
The following morning the production supervisor checked the overnight data and was amazed to see that the oil was now flowing again. Not only was it flowing again but production had leapt up to 21BOPD! All data was rechecked but the same results were arrived at.
It is too early to estimate how long this particular well will continue but the facts remain as follows:
- The well was declared unproductive (dead) before the application.
- The FWTO was unintentionally pushed into the formation, so revival of the well was totally unexpected by all parties.
- Residual FWTO from the application due to Hydrostatic Pressure and Gas Lifting entered the formation.
- The residual FWTO revived the well.
- The FWTO cleared all the contaminants in the flowline and dumped them in the separator.
- Not all wax in the Flowline was returned to liquid phase but it is expected that if the material removed from the separator is continuously mixed with the FWTO used then all wax will be returned to liquid phase and the recovered hydrocarbons can be sent for processing.
It is expected that the FloWell treated flowline will resist any further wax build-up for an extended period due to one of the effects of making pipe-walls resistant to initial wax crystal attachment and growth as we have seen in all other application but the period of time here is speculative only.
FloWell exceeded all expectations in a very
difficult application and extremely low ambient temperatures.