Schlumberger

Case Study: BaSOL 2000 HP Scale Dissolver Delivers In Situ Decontamination of Radioactive ESPs Onshore Kuwait

Cost-saving remediation technique eliminates unnecessary well shut-in and topside handling of NORM-contaminated equipment

Challenge: Decontaminate radioactive ESPs to prevent unnecessary prolonged shut-in and mitigate costs of pump reconditioning.

Solution: Apply BaSOL 2000 HP scale dissolver for in situ removal of naturally occurring radioactive material (NORM) sulfate scale.

Result:

  • Reduced well downtime and remediation time.
  • Avoided backlog of stored contaminated equipment.
  • Improved QHSE profile by eliminating handling of NORM at surface.
  • Realized cost savings from economical treatment solution.

Decontaminate radioactive ESPs while decreasing time and cost

NORM scale deposits within ESPs and other artificial lift assemblies can cause mechanical failure, shortening ESP service life and hindering production. Conventional remediation techniques entail shutting in wells, removing equipment, and decontaminating NORM before ESP repair and maintenance can be performed. One operator producing onshore Kuwait sought to decontaminate its radioactive ESPs with an in situ solution to prevent unnecessary shut-in and decrease costs and rig time.

Improve operational efficiency with in situ scale dissolver

Schlumberger recommended applying BaSOL 2000 HP scale dissolver, to establish optimal pH conditions for in situ removal of NORM sulfate scale. The active dissolution and catalysis agents in the scale dissolver ensure a rapid reaction rate and provide a dissolution capacity of up to 80 g/L [0.67 lbm/galUS]. To demonstrate the effectiveness of the scale dissolver prior to field application, Schlumberger treated NORM-contaminated ESP strings that had previously been removed from well assemblies. All ESP components—including the motor and impeller sections—were rendered free of scale and successfully decontaminated.

Reduced well remediation time and cost

The lower part of the completion was shut off by a thru-tubing plug and cement. The upper part of the completion with the ESP was flushed with diesel then treated to render the NORM scale contaminant water-wet. Heated BaSOL 2000 HP scale dissolver was circulated within the ESP assembly, and continual sample analysis was performed topside to confirm optimal dissolution conditions. A production logging tool containing a gamma ray densitometer was run before and immediately after the treatment.

Comparison of the gamma ray densitometer data from before and after the BaSOL 2000 HP scale dissolver application confirmed that no radiation was present after treatment, indicating successful dissolution and removal of NORM scale from the ESP. During the operation, the cleaned ESP required changeout. The failed, but now cleaned, ESP could be returned to the owner for maintenance and refurbishment and changed out without increasing the backlog of tools waiting for topside treatment. Additionally, the QHSE profile improved from avoiding surface handling of NORM-contaminated materials. The scale dissolver helped the operator reduce well downtime, well remediation time, and costs.

BaSol 2000 HP Scale Dissolver Delivers In Situ Decontamination of Radioactive ESPs, Onshore Kuwait

Conventional remediation techniques require well shut-in, equipment removal, and NORM decontamination before ESPs can be repaired.


Download: BaSOL 2000 HP Scale Dissolver Delivers In Situ Decontamination of Radioactive ESPs, Onshore Kuwait (0.19 MB PDF)

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