A new cement retarder was developed to be used in aged mixwater, CR-130. Aubin’s CR-130 was successfully deployed for a Middle East customer, to allow them to blend and store the mix water as required.
The client faced many challenges from the outset, including:
Previously, the client dry-blended the retarder but a change to using pre-hydrating in aged mix-water created issues with setting times
Erratic cement slurry thickening times led to the forming of unwanted plugs within tubing, resulting in unwanted costs and lost time
The customer required a retarder that delivered similar performance as the previous dry blended additive but would deliver reproducible performance in their new preparation method
Aubin approached this by collating all the details from the customer before running extensive lab tests to analyse the issue. Once the cause of the incompatibility was established, testing began to design a new product.
We also enlisted the help of the Aberdeen University Master’s Project to understand the problem, as it didn’t seem to be common within the industry.
Our team established how the current additives were being used involved prolonged storage of mixwater, where the retarder being used had been designed for use in dry blending with cement (it had 15 years of effective case history with the client in this way). The formulation when placed in mixwater for prolonged periods would form a complex with polymers contained within other additives, rendering the retarder ineffective.
A new cement retarder was manufactured that could be used in aged mixwater, CR-130.
CR-130 was successfully deployed in the field and enabled the customer to blend and store the mixwater as required.
The product has been utilised by the client for several years, with mixwater being left for prolonged periods including polymer-based fluid loss additives and dispersants. There have been no reports of LTIs and no plugs set in unwanted sections of tubular.
As a result, the chemical CR-120SB which had previously been used on similar projects was replaced with CR-130, which achieved better results.