Abstract:
The main objective of this work is to experimentally investigate the carbonatic scaling on metallic coupons (stainless steel 316L, Inconel 718, and Super Duplex 2507, and Super Duplex 2507 coated with Diamond-Like Carbon (DLC)) under simulated wellbore conditions. The experiments were performed at high temperature (100 °C) and high pressure (100 bar) in a novel experimental prototype (patent BR10202101340). In order to represent the oilfield environment, petroleum and water (total salinity of 164.000 mg/L) samples were used in the experiments. The scaling process design was based on the ASTM G184. The coupons were mounted in a rotating cage and exposed to CaCO3 crystals precipitation and adhesion induced by system depressurization. The rotation speed was maintained at 125 rpm in order to represent turbulent flow conditions. Scale mass was determined by gravimetry. Qualitative characterization included in situ photomicrographs and microphotographs of the coupons to identify CaCO3 polymorphs and their size distribution. The results showed that the base material does not significantly influence the quantity of scale deposited in the tested range. The incrusted masses ranged from approximately 20 to 58 mg, with no clear trend favoring material type or surface finish. The deposition was similar among Inconel 1718, Super Duplex 2507, and 316L stainless steel samples. A visual and gravimetric observation was that coupons positioned externally on the cage had a visibly greater average mass of scale compared to internal coupons. Aragonite was the predominant polymorph, with evidence of layering, where a denser, more compact layer of calcite was found beneath the aragonite. The oil presence did not affect the polymorphism but showed a clear tendency to agglomerate the CaCO3 crystals. This study utilized an innovative methodology by adopting thinner coupons (1.5 mm thick) compared to the ASTM G-170-06 standard (3.0 mm thick). This was based on preliminary results indicating significant variation in incrusted mass between the external and internal faces of the coupons as a function of rotation. The finding that material type had a limited impact suggests that factors like brine composition and flow regime play a more relevant role in crystal adherence under the operational conditions analyzed. The results address a gap in the scientific literature regarding experimental studies that represent conditions close to those found in the oil and gas industry.
Referência:
PEREIRA, F.A.R.; FEJOLI, R.F.; STREY, N., CAMPOREZ, R.; OLIVEIRA, J.; SCANDIAN, C.; SILVA, G.M.L.; SCHLUTER, H.E.; MARTINS, A.L.; CASTRO, B.B.; ALDEIA, Wagner; LOURENÇO, Vitoria Silva. Scaling of CaCO3 crystals on DLC-coated and metal alloys. In: SPE SCALE SYMPOSIUM, 2026, Aberdeen – Scotland – UK. Proceedings… 10p.
Acesso ao trabalho no site do Evento:
https://onepetro.org/SPEOSS/proceedings-abstract/26OSS/26OSS/D022S014R001/799543