Synthesis and Evaluation of a New Acryloyl-Based Copolymer as Kinetic Hydrate Inhibitor for Sour Gas Environments

Abstract

Blockage of gas flow lines by gas hydrates is a major problem in the oil and gas industry, which leads to severe safety issues and causes economic losses. Kinetic hydrate inhibitors (KHIs) are water-soluble polymers that are employed to circumvent this problem due to their effectiveness at low dosage, which makes logistics (transport, storage, and pumping) less costly particularly in offshore operations. However, some of the currently available KHI polymers have subcooling constraints against class I hydrates in high sour gas conditions, which limit their utilization. In this Article, we report a new KHI copolymer synthesized from N-acryloyl pyrrolidine and N-acryloyl piperidine monomers. Detailed characterization and compatibility studies were carried out using a variety of techniques and tests. The rocking cell test demonstrated the new formulation’s effectiveness to a high subcooling temperature of 8.5 °C at 140 bar of a gas mixture containing a high concentration of CO2 and H2S. The performance of the copolymer was investigated at 2% and 3% dosage, where the increased dosage of copolymer showed a higher subcooling temperature. Collectively, these results set a stage for the design, development, and evaluation of a new type of polymers as an effective KHI.

Multi-functional Flow Assurance Chemicals: Corrosion and Kinetic Hydrate Inhibition from Maleic Anhydride:N-Vinyl Caprolactam Copolymers and Synergists

“…The corrosion inhibition efficiency was now 99.7%, possibly higher as the resistance to iron oxidation was now so high that it caused an overload during the test. It should be noted that sulfur synergists are added to CI surfactant blends only for sweet corrosion, but not needed for sour corrosion as it already has H 2 S. , Therefore, it is possible that our maleic-based KHI polymers will function even better in sour gas as CIs than in sweet gas …”

“…It should be noted that sulfur synergists are added to CI surfactant blends only for sweet corrosion, but not needed for sour corrosion as it already has H 2 S. 1,2 Therefore, it is possible that our maleic-based KHI polymers will function even better in sour gas as CIs than in sweet gas. 75…”

Corrosion Inhibition of Carbon Steel in a Sour (H2S) Environment by an Acryloyl-Based Polymer

“…The acryloyl-based copolymer employed in this work is shown in Figure . Detailed synthesis and characterization using nuclear magnetic resonance (NMR) and gel permeation chromatography have been published. , Additional material properties of the copolymer and further analytical studies using FT-IR, TGA, and DSC are included in the Supporting Information.…”

“…Recently, we proposed a new acryloyl-based copolymer KHI for sour environments with a high sub-cooling temperature of 8 °C, which is able to mitigate structure I-type gas hydrates. , Here, we demonstrate that such a material can also be used as an effective CI in a sour environment. Corrosion inhibition properties of the polymer were studied, which included electrochemical testing via linear polarization resistance (LPR), potentiodynamic polarization (PDR), and high-pressure high-temperature (HPHT) autoclave tests under field-simulated conditions for gas production and wet sour crude processing.…”

Kinetic Hydrate Inhibition from Thermoresponsive Poly(2-amino-2-oxazoline)s: Size and Shape of the Hydrophobic Groups Are Critical for Performance

“…Commercial KHI polymers include polymers and copolymers of N -vinyl lactam and substituted methacrylamides such as N -isopropylmethacrylamide. − A range of other acrylamide and methacrylamide-based polymers such as those based on N -acryloylpyrrolidine, N -acryloylpiperidine and N -acryloylmorpholine have also been reported (Figure ). − Many of these polymers are thermoresponsive, exhibiting a cloud point temperature ( T cp ) or lower critical solution temperature (LCST) in water at typical KHI dosages (0.1–1.0 wt %). The T cp or LCST is the temperature at which the water-soluble polymer undergoes a phase change from a one-phase system to a two-phase system with high polymer concentration mesoglobules dispersed in a low concentration polymer solution, first visually noticeable by clouding of the solution due to the refractive index difference between the two phases.…”