SUCCESSFUL TRSSSV CLEAN-OUT WITH WELL CLEANER® WISHBONE HONER IN CASPIAN SEA

Background

An operator in the Caspian Sea was experiencing issues with the tubing-retrievable subsurface safety valve (TRSSSV) in a producing well.  During wellhead integrity testing in both 2017 and 2018, the TRSSSV failed “as found” tests and only passed after extensive troubleshooting. Later, in September 2018, further test results confirmed that the TRSSSV was not holding. Subsequent slam tests did not resolve the issue, and control line fluid return volume was lower than expected.

In early 2019, the client initially planned on running a TRSSSV exercising tool after a slickline (SL) drift run. Welltec®, having previously provided successful services for this client, was primarily brought to the site as a contingency plan for clean-out operations.

OPERATION

The 4.64” SL drift run discovered that the 5” pipe was full of scale, and the client determined that scale was preventing the TRSSSV from closing. After discovering the scale, Welltec’s tools were reconsidered for the main operation. The outer diameter of Welltec’s toolstring was 3.5” and could reach target depth for clean-out even with the scale restricting the inner diameter of the tubing.

The Well Cleaner® Wishbone Honer (WBH) had previously been tested for this client, so there was little question about its capabilities. After several technical discussions, the WBH was chosen as the primary option. During rig up, the client added another scope to the job: cleaning the autonomous shutdown valve (ASV) in a single run.

Welltec® performed two successful runs using the Well Tractor® and WBH, cleaning the scale from the TRSSSV. After completing the second run, the WBH cleaned the ASV on the way back up hole. After the runs, a 100% SQ inflow test confirmed that the TRSSSV was fully operational.

ACHIEVEMENTS

The WBH performed flawlessly and returned the TRSSSV to full functionality after only two clean-out runs. Additionally, Welltec® was able to expand the scope of the job per the client’s request by using the WBH to clean the ASV at the end of the second run.

Running this clean-out operation on e-line resulted in several benefits, including reduced operational time due to faster rig up and rig down, less equipment mobilized, and fewer personnel needed to monitor the operation. Welltec’s two successful clean-out runs saved the client the trouble of running four other contingency options, resulting in significant time and cost savings.

The client was extremely satisfied with Welltec’s results and, when asked for feedback, stated, “Excellent Job!”

WELL TYPE: OIL PRODUCER
MAXIMUM DEVIATION: 88°
PRESSURE AT TD: 5714 psi (394bar)
MAXIMUM DEPTH: 13190ft(4023)MD
MAXIMUM DEPTH IN OPERATION: 10571 ft MD
MAXIMUM TEMPERATURE: 2154°F (68°C)
DISTANCE TRACTORED: 2297ft (700m) average each run

 

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