Optimization of injection-withdrawal schedules for underground gas storage in a multi-block depleted gas reservoir considering operation stability

ABSTRACT

Underground gas storage (UGS) is an important facility to overcome the imbalance between natural gas supply and demand. In this paper, an optimization model of injection-withdrawal scheduling for UGS in a depleted gas reservoir is established to find the optimal operating state of the gas storage facility. Faults are widely developed in reservoir, which can divide a full reservoir into several pressure disconnected reservoir blocks (RB). Considering that the unbalanced pressure distribution of reservoir will significantly affect the stable operation of UGS, the optimization model aims to minimize the deviation degree of pressure between RBs under the condition of satisfying the gas injection-withdrawal requirements. The decision variables are the number of operating wells and the flow rate of a single well of each RB. A series of equality and inequality constraints are developed, including maximum inventory of RB, maximum pressure of RB and maximum flow rate of a single well. To verify the validity of the proposed method, the optimization model is applied to an actual UGS in a depleted gas reservoir in China. The GAMS modeling system and DICOPT solver are adopted to solve the optimization problem. The results show that the deviation degree of pressure between RBs of the optimized scheme is about 75% lower than that of the empirical scheme. In the empirical scheme, there is an extremely high-pressure RB with a maximum pressure of 43.98 MPa, which exceeds the pressure limit of 5.38 MPa. However, all RBs meet the pressure requirement in the optimized scheme. Overall, the optimized scheme can effectively reduce the deviation degree of pressure between RBs and avoid the occurrence of extremely high-pressure RB.

KEYWORDS:

• Operation optimization
• underground gas storage
• depleted gas reservoir
• gas injection and withdrawal
• reservoir pressure

Acknowledgments

This work was supported by the National Natural Science Foundation of China [51704253].

Disclosure statement

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

Nomenclature

Table

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [51704253].

Notes on contributors

Jun Zhou

Jun Zhou received the B.S. degree and Ph.D. degree in oil-gas storage and transportation engineering from China University of Petroleum, Beijing, China, in 2015. From 2015 to 2019, he was a Lecturer in Southwest Petroleum University, Chengdu, China. Since 2020, he has been an Associate Professor. He is mainly engaged in the optimization design of oil&gas pipeline network and underground gas storage.

Jinghong Peng

Jinghong Peng received the B.S. degree in oil-gas storage and transportation engineering from Southwest Petroleum University, Chengdu, China, in 2017. He is currently pursuing the Ph.D. degree in oil-gas storage and transportation engineering at Southwest Petroleum University, Chengdu, China. His research interest includes optimization of natural gas pipeline network operation and optimization of underground gas storage scheduling.

Guangchuan Liang

Guangchuan Liang received the B.S. degree and Ph.D. degree in oil-gas storage and transportation engineering from Southwest Petroleum University, Chengdu, China, in 2003. Since 1996, he works at the School of Petroleum Engineering, Southwest Petroleum University. He has been an Associate Professor in 2013. His research interest mainly includes the optimization design of oil&gas gathering and distribution system and multiphase flow research.

Jianhua Sun

Jianhua Sun received the B.S. degree in oil and natural gas engineering from China University of Geosciences, Beijing, China, in 2005. She is currently a senior engineer with PipeChina Zhongyuan Gas Storage Limited Liability Company. Her research interest mainly includes construction and operation management of underground gas storage.