Technical Objective:
To conduct a trial test to remove hard scale from production tubing using mechanical means to restore full bore access.
Well type:
Vertical oil well, 4 1/2-in tubing size.
Peak Solution:
Peak Torque-Action Debris Breaker wellbore clanup and debris removal tool: 2 1/2-in torque mandrel with 3.70-in and 3.83-in cutter subs.
The Challenge:
During a drift run in 2013, a customer detected accumulated scale in the production tubing of an oil well. The well had a history of scale buildup and a previous downhole solid sample presented 95 per cent iron compounds – iron oxide, siderite, mackinawite, and pyrrohtite as well as calcium carbonate.
Several attempts at acid descaling using 15 per cent and 20 per cent Hydrogen Chloride (HCl) yielded moderate results but it was unable to fully clear the obstructions just below surface.
Scale left in the completion as a bridge was not acceptable to the customer and a trial test was proposed to attempt to break the hard scale using mechanical means.
Considerations:
The following key requirements and concerns were highlighted:
Summary:
A trial test of Peak’s Torque-Action Debris Breaker tool was initiated to remove the hard scale in 4 1/2-in production tubing.
A 3.83-in Torque-Action Debris Breaker tool was run in hole and tagged an obstruction at 450 ftkb. The tool was jarred down mechanically in the well using 10 ft of 1.875-in toolstring. With each downward jar, the unique helically split torque sub applied a short duration of rotational torque to the cutter below clearing 30 ft of obstruction to reach 512 ftkb. Further jarring cleared this obstruction and continued to 539 ftkb. A smaller 3.7-in OD cutter was then run in hole.
Many areas of tight and hard scale were consistently cleared at a rate of 3,000 ft/hr until the crossover was reached at 6,770 ftkb.
The 3.83-in Torque-Action Debris Breaker tool was re-run in hole with 5 ft of 1.875 in additional stem for added weight and continued to clear the scale to 1,350 ftkb before the trial was ended.
The hard scale was successfully cleared using the Torque-Action Debris Breaker tool where previous acidizing attempts were not as successful.
Value to Customer:
The trial was declared a success by the customer with all operations carried out safely and efficiently.
Product Code: 117