(165b) 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.