JPH173210 WAB Geo

Well repair via high-temperature WAB® to revive geothermal producer

  • WELL TYPE
    Geothermal producer
  • RENEWABLES
    Welltec pilot success in renewables market segment
  • ENGINEERED WORKOVER
    Cost savings of USD 8 mm vs drilling of new well
  • HIGH TEMPERATURE APPLICATION
    To sustain up to 550°F at full production
  • CAPEX-EFFECTIVE
    Well-rejuvenation methods
  • LOCATION
    Philippines

Background

A geothermal well operator had to shut in its most prolific producer (20 MW) due to 13-3/8” casing failure and the loss of the 7” slotted production liner from acidic corrosion. Welltec® offered a Welltec Annular Barrier® (1214WAB) solution providing a solid base for hydrostatic support to the column of cement slurry placed above it and would prevent the curing cement from becoming contaminated. The 1214WAB would also offer anchoring support to the casing string in the event of thermal contraction or expansion of the casing string during production or shut-down operations.

Operations

The 1214WAB was adapted to incorporate non-elastomeric isolation valves & burst discs to bleed off high-pressure steam build-up behind the casing. And was run just above the 9 5/8” casing tailpipe and set inside the existing 13 3/8” casing. 2nd stage cementing was performed above the installed 1214WAB. During deployment, water flooded the well to keep temperatures ≤ 212°F—full production temperatures will be 545°F. The 1214WAB supported the cement column during curing and prevented free-water/acid from contaminating the cement or reaching the surface.

Achievements

This was the first time a WAB has been used to revive a geothermal well. This job also marked the first time Welltec worked in a geothermal well, in the Philippines, and deployed the WAB with second-stage cementing equipment in Asia. To drill a new well would have cost the client between USD 9 million and USD 12 million. Welltec’s solution enabled the client to execute life-of-well, CAPEX-effective well-rejuvenation measures, proving the value of engineered well remediation. WAB assembly was adapted to incorporate high temp sealing system, non elastomeric isolation valves and incorporated burst discs to bleed off high-pressure steam within application that will reach 550°F at full production.

Tools Applied