Underground Gas Storage Construction in Gas Fields with Oil Ring and Edge and Bottom Water: A Case Study

ABSTRACT

Most underground gas storages (UGSs) are constructed in gas fields, but there are few UGS examples constructed in a gas field with an oil ring and edge/bottom water (OR-EBW-gas field). In areas where suitable gas fields are not available for USG development, existing gas fields with oil ring and edge and bottom water have to be used to construct UGS to balance the seasonal natural gas consumption and supply. Compared with conventional gas reservoirs, fluid distribution is much more complicated in OR-EBW-gas fields and there exist different modes for storage space plan, which brings up more uncertainty for the UGS construction. In this work, an active UGS construction in an OR-EBW-gas field is studied using a comprehensive compositional numerical model. The operation parameters are firstly determined through detailed sensitivity studies. UGS construction schemes employing different porous medium spaces are then investigated to determine the optimal one. The results indicate that UGS constructed using gas cap area is the optimal scheme. After 20 I/W cycles, the predicted working load of the UGS is 1.726 × 10⁸ m³, which reaches the designed value of 1.7 × 10⁸ m³. The incremental cumulative water production and oil production are 0.21 × 10⁴m³ and 0.42 × 10⁴m³ respectively. The study shows that it is crucial to prevent the intrusion of edge water for UGS construction in an OR-EBW-gas field. The oil ring is not suitable for UGS construction due to its poor petrophysical property, but can be used as a natural barrier to separate gas cap and edge water. The formation pressure needs to be improved when the gas cap, oil ring and edge water are selected as USG construction zones. However, it will also lead to a significant increase in the formation pressure near the main control fault, which leads to a high risk of fault failure.

KEYWORDS:

• Digital simulation
• underground gas storage construction
• gas field with oil ring and edge and bottom water
• parameter optimization
• sensitivity analysis

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This project is supported by the technical funds of the Chongqing Technology Innovation and Application Development Special Project “R&D of Large-scale Underground Natural Gas Storage Equipment”(cstc2020jscx-msxmX0189), and Scientific Research Funding Project of Chongqing University of Science and Technology (No.ckrc2021040).

Notes on contributors

Xiaoliang Huang

Xiaoliang Huang, holds PhD in Petroleum Engineering. He is a now a professor in School of Petroleum and Natural Gas Engineering in Chongqing University of Science and Technology. His research includes unconventional reservoir development and numerical simulation.

Qiqi Wanyan

Qiqi Wanyan holds a PhD in Mineral Survey and Exploration. He is a senior engineer at the Underground Storage Research Center of PetroChina Exploration and Development Research Institute. The main research direction is the design of gas reservoir type gas storage and salt cave type gas storage.

Junyu You

Junyu You holds a PhD in Petroleum Engineering. He is working as a lecturer in School of Petroleum and Natural Gas Engineering in Chongqing University of Science and Technology. His research includes unconventional reservoir development and reservoir numerical simulation.

Hongcheng Xu

Hongcheng Xu holds a MS in Fluid Mechanics. He is currently a senior engineer at the Underground Storage Research Center of PetroChina Exploration and Development Research Institute. His main research direction includes the design of UGS operation schemes and inventory evaluation.

Nanxin Yin

Nanxin Yin holds a PhD in Geological Engineering. He is a now a senior engineer in School of Petroleum and Natural Gas Engineering in Chongqing University of Science and Technology. His research area includes oil and gas field development geology, reservoir description, 3D geological modeling.

Lina Song

Lina Song holds a MS in Petroleum Engineering. She currently works as an engineer in the Underground Storage Research Center of PetroChina Exploration and Development Research Institute. The main research direction is gas reservoir type gas storage scheme design and inventory evaluation.