Research on the Performance of Cement-Based Composite Borehole Sealing Material Based on Orthogonal Test

Shuqi Xu; Shanyang Wei; Hongfei Xie; Yuzhu Liang; Xuzheng Zhu; Weidong Luo; Fuzhi Zhu

doi:10.1021/acsomega.3c09804

Research on the Performance of Cement-Based Composite Borehole Sealing Material Based on Orthogonal Test

ACS Omega. 2024 Feb 22;9(9):10799-10811. doi: 10.1021/acsomega.3c09804. eCollection 2024 Mar 5.

Authors

Shuqi Xu¹, Shanyang Wei¹, Hongfei Xie², Yuzhu Liang², Xuzheng Zhu¹, Weidong Luo³, Fuzhi Zhu³

Affiliations

¹ Mining College of Guizhou University, Guiyang, Guizhou 550025, China.
² Science and Technology Innovation Department of Guizhou Energy Group, Guiyang, Guizhou 550081, China.
³ Guizhou Energy Group Research Institute Co., Ltd., Guiyang, Guizhou 550025, China.

Abstract

In order to achieve better sealing of boreholes, the performance of sealing materials is modified to improve the efficiency of coalbed methane extraction. In this paper, a new type of cement-based hole sealing material was prepared by using silicate cement (PC) and cement sulfoaluminate (SAC) as raw materials, supplemented with various additives, such as fly ash, Na₂SO₄, Ca(OH)₂, and poly(vinyl alcohol) (PVA) fiber. The effects of these additives on the fluidity, setting time, and compressive strength of the PC-SAC compounded cementitious pore sealing material were investigated by orthogonal tests, and the hydration process and hydration products were analyzed by X-ray diffraction (XRD), thermogravimetry-differential thermogravimetry (TG-DTG), and scanning electron microscopy (SEM). The results show that the water-cement ratio has the most significant influence on the various properties of the material; the two additives of Na₂SO₄ and Ca(OH)₂ play a key role in the setting time of the material; the optimal group, i.e., water-cement ratio of 0.5, fly ash of 5%, Na₂SO₄ of 1%, Ca(OH)₂ of 0.75%, and PVA fibers of 0.8%, is obtained by the orthogonal test method, which is the closest to the actual needs of the project. The hydration products of the optimized materials have obvious changes, and the needle-like AFt and C-S-H increase so that the performance of the materials has been significantly improved.