"Kinetics of Scale Formation in Oil and Gas Production – Experimental setup"
Abstract
Scale formation tend to be a key problem regarding flow assurance in oil and gas production. In search for understanding the kinetic behavior of scale precipitation, a series of different methods have been used in the past.
The most common method is “bulk jar test”, which is a static system with decreasing saturation as precipitation occurs. Representation of relevant properties found in hydrocarbon production are therefore sparsely reported (Sanjuan).
Challenges in experimental design and embodiment, are specially associated to kinetic mechanisms.
The early stages of nucleation, are highly dependent on the sensitivity of analytical method. The focus has been towards the mechanism of bulk precipitation throughout the reported literature. The perception of surface scale formation, has been leading towards deposition of crystals already present in the bulk solution.
However, lately there has been several studies suggesting otherwise. It seems that bulk precipitation and surface deposition are separate mechanisms, with their respective separate kinetics ( (Morizot), (Chen), and (Sanni)).
In order to accommodate an enhanced understanding of scale formation mechanisms and its kinetic behavior, an experimental setup with a new approach is suggested. The setup introduces in situ measurement of scale formation kinetics, utilizing nano X-ray computed tomography accompanied with image analysis.
A once through flow cell allows investigation of scale deposition on a carbon steel sample, with the ability to alter operating conditions. The setup will mainly be used to investigate the scale mineral FeCO3 which are found in the upper completion in oil production.
The setup will allow measurements of scale formation as a function of temperature, flow regime, saturation and CO2 partial pressure. The work will focus on determining the relation between the kinetics of surface and bulk precipitation mechanisms. In order to describe the early stages of nucleation mechanisms, it is important to utilize a technique with high sensitivity. Nano X-ray tomography is able to detect particles down to 60 nm, hence give valuable insight to the early appearance of a solid phase.