Stability Analysis on the Long-Term Operation of the Horizontal Salt Rock Underground Storage

Chengzhong Zhang,Weiwei Li,Qiang Zhang,Junbao Wang,Zhanping Song,Song-He Wang

doi:10.1155/2021/6674195

Abstract

The construction of the vertical cavern in the salt dome deposit can meet the requirements of both storage capacity and tightness. However, if the vertical cavern is still used as the design shape of the salt rock underground storage in the layered salt rock deposit, the high design capacity cannot be guaranteed while the tightness is satisfied. In this case, the use of a large-span horizontal cavern as the design shape of the salt rock storage can not only effectively increase the design capacity of the storage, but also solve the problems such as the stability and tightness of the storage during the operation period by improving the structural form and working mode. Based on this, the ellipsoid-shaped horizontal salt rock underground storage is taken as an example, and a single-cavern horizontal salt rock underground storage model with different diameter-to-height ratios is established by using FLAC3D software. The change law of vertical and horizontal displacements, volume loss rate, and plastic zone distribution of salt rock storage changing with the diameter-to-height ratio are studied, and the optimal diameter-to-height ratio is determined. And then the long-term operation process of the double-cavern horizontal salt rock underground storage under the optimal diameter-to-height ratio is simulated, and the optimal pillar width is obtained.

Highlights

Energy is the material basis for the survival and development of human society, occupying an important strategic position in the national economy [1,2,3]
Chen et al [33] studied the influence of gas pressure and the ratio of long and short axes on the stability of double-cavern salt rock underground storage with small spacing by using numerical simulation methods. e results showed that gas pressure has a significant effect on the stability of underground salt rock storage, while the ratio of long axis to short axis has an important impact on the volume loss rate and roof settlement of underground salt rock storage
Relevant scholars have carried out more in-depth research on the long-term stability of salt rock underground storage, and most of their research objects are vertical salt rock storage

Summary

Introduction

Energy (oil and natural gas) is the material basis for the survival and development of human society, occupying an important strategic position in the national economy [1,2,3]. Chen et al [33] studied the influence of gas pressure and the ratio of long and short axes on the stability of double-cavern salt rock underground storage with small spacing by using numerical simulation methods. E results showed that gas pressure has a significant effect on the stability of underground salt rock storage, while the ratio of long axis to short axis has an important impact on the volume loss rate and roof settlement of underground salt rock storage. E change law of volumetric loss rate, stress, and plastic zone development of underground salt rock storage under different diameter-to-height ratios are studied, and the optimal diameter-to-height ratio is determined On this basis, the long-term operation process of double-cavern horizontal salt rock underground storage is simulated numerically, and the optimal pillar width is obtained

Physical Mechanics Model

Stability Analysis of Single-Cavern Horizontal Salt Rock Underground Storage

Stability Analysis of Double-Cavern Horizontal Salt Rock Underground Storage

Findings

Conclusions