Downhole Jetting Tool takes samples and restores production
- Well type Oil producer
- Location Norway
A client in Norway had a well with no injectivity or productivity (a dead well), after only producing ~1/2 well volume following a re-completion. It was suspected that the well and its screens had been filled up and clogged by particles from the completion fluid that was initially placed inside and outside the screens.
The client wanted to obtain samples of the fill and fluid blocking the screens, and from that find suitable chemicals to flush the screens and re-open the reservoir flow path.
Welltec proposed a solution that would fulfill clients wishes in two stages:
1) Sample both solids and liquids at Target Depth (TD) using the Well Cleaner® Downhole Jetting Tool (DJT) with a new valve setup.
2) Convey suitable chemicals down to TD with Well Cleaner DJT, and flush the screens to re-open them.
Full testing was carried out to find the best setup of pumps, valves and flappers. The results showed that it was possible to both sample and preserve solids and liquids from TD to surface.
This operation would introduce the Well Cleaner DJT as a sampling tool of liquids and solids collected in separate chambers, and as a safe and efficient means of conveying chemicals to be precisely applied to flush and re-open screens.
The DJT was filled with 6.8 liters of the surfactant ‘Safe Surf’ that was suited to dissolve the emulsion collected during sampling. As the surfactant was lighter than the well fluid, the DJT was initiated as deep as possible, accounting for the upward migration that would take place.
The DJT was kept running while moving over the screens, held at stations three meters apart for two minutes each time. The sequence was repeated while flushing well fluid mixed with surfactant.
The Well Cleaner DJT – primarily a cleaning tool – was proven to be capable of sampling and preserving both solids and liquids in separated chambers from TD to surface.
Using the Well Cleaner DJT to spot and flush suitable chemicals, screens with no injectivity were successfully reopened to restore the well to production.
The DJT also reduced the volume of chemicals needed and saved the client from what was expected to be a much bigger clean out operation.