Evaluating Wax Gelation Risk for Restart Operations - Closing the Gap between Academic Research and Industrial Applications

Evaluating Wax Gelation Risk for Restart Operations – Closing the Gap between Academic Research and Industrial Applications

Zhenyu Huang, Assured Flow Solutions LLC

The problem wax gelation is well known to the flow assurance industry. A waxy crude oil can form gels of high viscosity and yield stress during shut-down, which poses significant concern for the pressure requirement during field restart. Despite recent advances in academic research to study this problem, the industry still relies heavily on conventional fluid testing and calculation methods to tackle wax gelation, which often leads to over-conservative mitigation strategies.

With the aim to resolve this disconnection, this presentation discusses the importance of understanding the complex rheological characteristics of the waxy gel in order to select appropriate experimental measurements and correctly interpret the results. Conventional rheological testing methods can be over-conservative, while more advanced characterization methods still need to be applied/analyzed with prudence.

In addition, restart modeling is an integral part to develop rigorous understanding of the pressure requirement in the field. In this presentation, the behavior of a waxy gel during restart will be discussed and several existing models will be carefully reviewed. Finally, the application of an in-house restart model to identify the restart challenges in the field is presented.