The Challenge
A major UK operator had a damaged 8” caisson and leaking valve at a depth of 80m subsea and a temperature of 6 degrees Celsius. They required two cement plugs to restore integrity to the caisson. Aubin was approached by the contract holder to provide cement slurry design and an additive pack, backed up with multiple cement tests.
What Happened?
Within 1 week, Aubin’s cement team designed a slurry comprising of the following additives:
| Cement | Dykerhoff Class G |
| Water | Fresh Water |
| Aubin Defoamer | DF-4 |
| Aubin Dispersant | CD-6L |
| Aubin Accelerator | CAX-1 |
Developed in Aubin’s fully equipped cement laboratory, the cement team work to API cement standard RP10b. The following tests were carried out to ensure that the cement performed to the standards required by the client:
After slurry design was completed and the full lab test results were shared with the operator, the products were chosen due to their availability and their CEFAS environmental profile.
The slurry was sent for an onshore trial to assess the placement and pumping through 1” diameter hoses. Based on the trial results, Aubin optimised the slurry design, which was then approved by the operator for field use.
The additives for the offshore cement slurry were mobilised together with Aubin cube moulds to allow representative samples to be taken from field. After the slurry was applied to form the first plug in the caisson, samples were returned to the cement laboratory for compressive strength testing.
Due to scheduling, Aubin’s cement team performed urgent, out of hours cement tests to provide speedy results to reduce operator downtime, fulfilling the service demanded by operator and contract holder.
The Result
The operator was extremely pleased with Aubins quick, out of hours service and the on-hand testing and custom slurry design. The response time from the Aubin cement team enabled the operator to minimise downtime, save costs and resolve the challenge promptly.
The expertise and thorough cement testing from the Aubin cement laboratory gave the operator full confidence to progress with the second stage of the operation and the final cement plug results were deemed successful.
