Texture, composition and properties of plugs formed by carbon dioxide hydrate and wax

Texture, composition and properties of plugs formed by carbon dioxide hydrate and wax Full article

Journal

Petroleum Exploration and Development
ISSN: 1876-3804 , E-ISSN: 2096-4803

Output data

Year: 2021, Volume: 48, Number: 6, Pages: 1462-1470 Pages count : 9 DOI: 10.1016/S1876-3804(21)60302-6

Tags

carbon dioxide hydratehydrate/wax plugplug texturehydrate decomposition

Authors

Skiba Sergey ^1,2 , Sagidullin Aleksey ¹ , Shapovalova Alexandra ¹ , Strelets Larisa ³ , Manakov Andrey ^1,2

Affiliations

1	Nikolaev Institute of Inorganic Chemistry, SB RAS, Ac. Lavrentiev Ave. 3, Novosibirsk 630090, Russia
2	Novosibirsk State University, Pirogova Str. 2, Novosibirsk 630090, Russia
3	Institute of Petroleum Chemistry SB RAS, Akademichesky ave., 4, Tomsk 634021, Russia

Gas hydrates and wax are the major flow assurance problems for the transportation of produced hydrocarbons through pipelines. However, in most research works both these two problems are studied separately. Although simultaneous precipitation or deposition of these compounds in pipelines can lead to different mitigation/prevention strategies, the investigations in which both these problems are considered simultaneously appeared only recently. There is no information in the literature on the texture/composition and features of decomposition process of mixed wax/hydrate plugs. At the same time, this information could be useful to understand how to treat the problem of formation of these plugs. In this work, three wax/gas hydrate plugs were collected at quasi-static conditions from a water-in-oil emulsion to study their texture, composition and the features of decomposition process. Powder X-ray diffraction and IR (infrared spectroscopy) analyses showed that the plugs consisted of wax and gas hydrate. Thermovolumetric and DSC (Differential Scanning Calorimetry) experiments showed that the main part of gas hydrate in the plugs at the ambient pressure started to decompose at about 268 K. This temperature was higher than the equilibrium temperature of carbon dioxide hydrate at this pressure, indicating that the gas hydrate in the plugs could be effectively preserved at temperatures below the ice melting point (273.2 K). It was found through observation of the hydrate decomposition process in the plugs under the microscope that the gas in the samples released in small bubbles, while the hydrate particles were not visible at this magnification, indicating that the hydrate was indeed highly dispersed in the samples. A residual wax was jelly-like after decomposition of hydrate in all the cases. Rheological experiments showed that the plugs residues after decomposition of the hydrates had higher yield points and viscosities than the initial waxy crude oil originally used for the experiments.

Skiba S. , Sagidullin A. , Shapovalova A. , Strelets L. , Manakov A.
Texture, composition and properties of plugs formed by carbon dioxide hydrate and wax
Petroleum Exploration and Development. 2021. V.48. N6. P.1462-1470. DOI: 10.1016/S1876-3804(21)60302-6 OpenAlex

Submitted:	Dec 1, 2020
Accepted:	Sep 30, 2021
Published online:	Dec 17, 2021

OpenAlex:

W4200517924

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