Molecular dynamics simulation of clay hydration inhibition of deep shale

Molecular dynamics simulation of clay hydration inhibition of deep shale

Zhang, Yayun (State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development; Sinopec Research Institute of Petroleum Engineering)
Xiao, C. (TU Delft Mathematical Physics)

2021

In the process of the exploitation of deep oil and gas resources, shale wellbore stability control faces great challenges under complex temperature and pressure conditions. It is difficult to reflect the micro mechanism and process of the action of inorganic salt on shale hydration with the traditional experimental evaluation technology on the macro effect of restraining shale hydration. Aiming at the characteristics of clay minerals of deep shale, the molecular dynamics models of four typical cations (K⁺, NH₄⁺, Cs⁺ and Ca²⁺) inhibiting the hydration of clay minerals have been established by the use of the molecular dynamics simulation method. Moreover, the micro dynamics mechanism of typical inorganic cations inhibiting the hydration of clay minerals has been systematically evaluated, as has the law of cation hydration inhibition performance in response to temperature, pressure and ion type. The research indicates that the cations can promote the contraction of interlayer spacing, compress fluid intrusion channels, reduce the intrusion ability of water molecules, increase the negative charge balance ability and reduce the interlayer electrostatic repulsion force. With the increase in temperature, the inhibition of the cations on montmorillonite hydration is weakened, while the effect of pressure is opposite. Through the molecular dynamics simulation under different temperatures and pressures, we can systematically understand the microcosmic dynamics mechanism of restraining the hydration of clay in deep shale and provide theoretical guidance for the microcosmic control of clay hydration.

Chemical inhibition
Clay mineral
Deep shale
Inorganic cation
Molecular dynamic simulation

http://resolver.tudelft.nl/uuid:a1581524-75d9-437a-94ee-6caa8cf82d8e

https://doi.org/10.3390/pr9061069

2227-9717

Processes, 9 (6), 1-17

Institutional Repository

journal article

© 2021 Yayun Zhang, C. Xiao