Study on the Effect of Cations on the Surface Energy of Nano-SiO2 Particles for Oil/Gas Exploration and Development Based on the Density Functional Theory

Jun Ni; Lei Zhang; Chengjun Wang; Weibo Wang; Ge Jin

doi:10.3390/molecules29040916

Study on the Effect of Cations on the Surface Energy of Nano-SiO₂ Particles for Oil/Gas Exploration and Development Based on the Density Functional Theory

Molecules. 2024 Feb 19;29(4):916. doi: 10.3390/molecules29040916.

Authors

Jun Ni¹, Lei Zhang², Chengjun Wang³, Weibo Wang¹, Ge Jin³

Affiliations

¹ Shaanxi Yanchang Petroleum (Group) Co., Ltd., Xi'an 710075, China.
² Key Laboratory of Theory and Technology of Petroleum Exploration and Development in Hubei Province, Department of Petroleum Engineering, China University of Geosciences (Wuhan), Wuhan 430074, China.
³ College of Chemistry and Chemical Engineering, Xi'an Shiyou University, Xi'an 710065, China.

Abstract

Although nano SiO₂ exhibits excellent application potential in the field of oil and gas exploration and development, such as drilling fluid, enhanced oil/gas recovery, etc., it is prone to agglomeration and loses its effectiveness due to the action of cations in saline environments of oil and gas reservoirs. Therefore, it is crucial to study the mechanism of the change in energy between nano SiO₂ and cations for its industrial application. In this paper, the effect of cations (Na⁺, K⁺, Ca²⁺, and Mg²⁺) on the surface energy of nano SiO₂ particles is investigated from the perspective of molecular motion and electronic change by density functional theory. The results are as follows: Due to the electrostatic interactions, cations can migrate towards the surface of nano SiO₂ particles. During the migration process, monovalent cations are almost unaffected by water molecules, and they can be directly adsorbed on the surface by nano SiO₂ particles. However, when divalent cations migrate from a distance to the surface of nano SiO₂ particles, they can combine with water molecules to create an energy barrier, which can prevent them from moving forward. When divalent cations break through the energy barrier, the electronic kinetic energy between them and nano SiO₂ particles changes more strongly, and the electrons carried by them are more likely to break through the edge of the atomic nucleus and undergo charge exchange with nano SiO₂ particles. The change in interaction energy is more intense, which can further disrupt the configuration stability of nano SiO₂. The interaction energy between cations and nano SiO₂ particles mainly comes from electrostatic energy, followed by Van der Waals energy. From the degree of influence of four cations on nano SiO₂ particles, the order from small to large is as follows: K⁺ < Na⁺ < Mg²⁺ < Ca²⁺. The research results can provide a theoretical understanding of the interaction between nano SiO₂ particles and cations during the application of nano SiO₂ in the field of oil and gas exploration and development.

Keywords: electrostatic action; nano SiO2; oil and gas exploration and development; quantum chemistry; salt water.

Grants and funding

This study was supported by the National Natural Science Foundation of China (Program No. 52204054) and the Innovation Capability Support of Shaanxi Province (Program No. 2023-CX-TD-31).