Abstract:
The main objective of this work is to experimentally investigate the carbonatic scaling on metalliccoupons (stainless steel 316L, Inconel 718, and Super Duplex 2507, and Super Duplex 2507 coated withDiamond-Like Carbon (DLC)) under simulated wellbore conditions. The experiments were performedat high temperature (100 °C) and high pressure (100 bar) in a novel experimental prototype (patentBR10202101340). In order to represent the oilfield environment, petroleum and water (total salinity of164.000 mg/L) samples were used in the experiments. The scaling process design was based on the ASTMG184. The coupons were mounted in a rotating cage and exposed to CaCO3 crystals precipitation andadhesion induced by system depressurization. The rotation speed was maintained at 125 rpm in order torepresent turbulent flow conditions. Scale mass was determined by gravimetry. Qualitative characterizationincluded in situ photomicrographs and microphotographs of the coupons to identify CaCO3 polymorphs andtheir size distribution. The results showed that the base material does not significantly influence the quantityof scale deposited in the tested range. The incrusted masses ranged from approximately 20 to 58 mg, with noclear trend favoring material type or surface finish. The deposition was similar among Inconel 1718, SuperDuplex 2507, and 316L stainless steel samples. A visual and gravimetric observation was that couponspositioned 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 layerof calcite was found beneath the aragonite. The oil presence did not affect the polymorphism but showeda clear tendency to agglomerate the CaCO3 crystals. This study utilized an innovative methodology byadopting 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 andinternal faces of the coupons as a function of rotation. The finding that material type had a limited impactsuggests that factors like brine composition and flow regime play a more relevant role in crystal adherenceunder the operational conditions analyzed. The results address a gap in the scientific literature regardingexperimental studies that represent conditions close to those found in the oil and gas industry.
Referência:
ALDEIA, Wagner; LOURENÇO, Vitoria Silva; MENEZES, Mayara Fernanda de Souza. Scaling of CaCO3 crystals on DLC-coated and metal alloys. In: SPE SCALE SYMPOSIUM, 2026, Aberdeen – Scotland – UK. Lecture… 11 slides. (SPE-231785-MS.)
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