TY - JOUR

T1 - Self-preservation of small gas hydrate particles in oils under stirring: Experimental results and computational model

AU - Skiba, S. S.

AU - Vlasov, V. A.

AU - Strukov, D. A.

AU - Manakov, A. Y.

N1 - Funding Information: Experimental studies performed in this work were supported by the Basic Research Program of the Russian Academy of Sciences (basic research program NIICh SB RAS No. 0236–2021-0001 ). Numerical studies performed in this work were carried out according to state assignments Nos. 121041600040–3 and 1021110317891-3-2.4.2 with the financial support of the Russian Foundation for Basic Research and the Tyumen Region (project No. 20-43-720002 ). Publisher Copyright: © 2022 Elsevier B.V.

PY - 2022/3

Y1 - 2022/3

N2 - In this work, the self-preservation of small (tens of μm) methane hydrate particles dispersed in oils was studied. The results of this work show that stirring in itself has no effect on the self-preservation of hydrate particles in oil suspensions. The particles undergo self-preservation under both static and stirred conditions. However stirring can lead to redistribution of oil components which may result in the disappearance of self-preservation. Accordingly to developed analytical model, it was shown that the effectiveness of self-preservation is determined by the value of the diffusion coefficient of methane in the pores of the ice crust. It was shown that for the samples with weak self-preservation, the diffusion coefficient of methane in the pores of the ice layer is close to 10−15 m2/s, while for the samples with effective self-preservation this value is an order of magnitude lower. Thus, the pore structure of the ice layer formed on the hydrate particles completely determines whether the self-preservation effect is manifested in a single experiment. The oil environment can allow for the formation of dense ice layers that can provide effective self-preservation. Our data show that the process of the appearance of ice layer and of evolution of its pore system on the surface of hydrate particles suspended in oils and thus the hydrates decomposition rates is of a stochastic nature. Therefore, the efficiency of self-preservation may differ significantly under similar external conditions.

AB - In this work, the self-preservation of small (tens of μm) methane hydrate particles dispersed in oils was studied. The results of this work show that stirring in itself has no effect on the self-preservation of hydrate particles in oil suspensions. The particles undergo self-preservation under both static and stirred conditions. However stirring can lead to redistribution of oil components which may result in the disappearance of self-preservation. Accordingly to developed analytical model, it was shown that the effectiveness of self-preservation is determined by the value of the diffusion coefficient of methane in the pores of the ice crust. It was shown that for the samples with weak self-preservation, the diffusion coefficient of methane in the pores of the ice layer is close to 10−15 m2/s, while for the samples with effective self-preservation this value is an order of magnitude lower. Thus, the pore structure of the ice layer formed on the hydrate particles completely determines whether the self-preservation effect is manifested in a single experiment. The oil environment can allow for the formation of dense ice layers that can provide effective self-preservation. Our data show that the process of the appearance of ice layer and of evolution of its pore system on the surface of hydrate particles suspended in oils and thus the hydrates decomposition rates is of a stochastic nature. Therefore, the efficiency of self-preservation may differ significantly under similar external conditions.

KW - Decomposition kinetics

KW - Flow assurance

KW - Gas hydrate

KW - Oil

KW - Self-preservation

UR - http://www.scopus.com/inward/record.url?scp=85124182977&partnerID=8YFLogxK

U2 - 10.1016/j.jngse.2022.104440

DO - 10.1016/j.jngse.2022.104440

M3 - Article

AN - SCOPUS:85124182977

VL - 99

JO - Journal of Natural Gas Science and Engineering

JF - Journal of Natural Gas Science and Engineering

SN - 1875-5100

M1 - 104440

ER -