# Mechanism of High-Temperature Thickening Regulation in Amide-Modified Ultra-High-Temperature Polycarboxylate Retarders

## TL;DR

Researchers improved high-temperature cementing by modifying retarders with DMAA, enhancing their performance in extreme conditions.

## Contribution

The study introduces DMAA-modified polycarboxylate retarders with enhanced high-temperature performance and explains their regulation mechanism.

## Key findings

- DMAA-modified retarders show superior high-temperature performance with lower dosage.
- The coupling of SH5L and Ca2+ delays cement hydration and crystallization.
- Polymer chain stretching at high temperatures improves Ca2+ binding and retardation.

## Abstract

What are the main findings?
The high-temperature retarding effect of retarders was improved by introducing DMAA monomers.The chelation between copolymers and Ca2+ inhibits early hydration and delays hydration time.The stretching of polymer chains at high temperatures enhances their high-temperature performance.The hydrolysis of amide groups in DMAA produces carboxyl groups enhancing the retarding ability.

The high-temperature retarding effect of retarders was improved by introducing DMAA monomers.

The chelation between copolymers and Ca2+ inhibits early hydration and delays hydration time.

The stretching of polymer chains at high temperatures enhances their high-temperature performance.

The hydrolysis of amide groups in DMAA produces carboxyl groups enhancing the retarding ability.

What are the implications of the main findings?
A high-temperature resistant retarder has been developed.An explanation for the dynamic regulation mechanism of high-temperature retarders at high temperatures has been provided.Technical support for deep high-temperature cementing operations was provided.

A high-temperature resistant retarder has been developed.

An explanation for the dynamic regulation mechanism of high-temperature retarders at high temperatures has been provided.

Technical support for deep high-temperature cementing operations was provided.

As oil and gas well development moves towards ultra deep formations, the high temperature at the bottom of the well causes the failure of copolymer retarders, leading to increased risk of oil and gas leakage and carbon emissions during cementing operations. To further ensure the safety of high-temperature oil and gas cementing operations, the influence of N,N-dimethylacrylamide (DMAA) on the high-temperature performance of copolymer retarders was explored. DMAA was introduced into copolymer retarders to form ultra-high temperature retarders. By analyzing the micro mechanism of copolymer retarders, the regulation of high-temperature retarders on the micro hydration process of cement slurry at high temperatures was revealed. Results showed that the cement slurry containing 3.0% SH5L (Pentameric copolymer retarder-introduced DMAA) exhibits a significantly similar thickening time with 3.4% SH4L (Quaternary copolymer-retarder) at 180 °C, demonstrating superior retardation performance at a lower dosage. The ultra-high-temperature polycarboxylate retarder SH5L was prepared by introducing the DMAA, enhancing its temperature resistance and retardation performance at high temperatures. The coupling of SH5L and Ca2+ retards the hydration and crystallization process of the cement slurry. The combination of rigid polycyclic structures and cationic monomers weakens the chelation between anionic groups and Ca2+, inhibiting the curling of polymers in ionic solutions. Polymer chains stretch with increasing temperature, enhancing their ability to bind with Ca2+ and improving their high-temperature retardation performance.