The integrated simulation technology of underground gas storage are composed with three key technologies including model building, model connection and model calibration. Based on high-precision simulation technology, combined with digital twin technology, the ground processes and facilities of underground gas storage achieve one-to-one reduction. The machine learning model and mechanism model are used to solve the connection problems of key boundary parameters, which realize the dynamic interaction from gas reservoir, wellbore to ground process. The real-time calibration method of gas injection and production process is established, which achieves the accurate calibration of integrated model. The digital and intelligent level of underground gas storage is improved greatly.
The underground gas storage (UGS) is an important means to solve the imbalance of seasonal gas consumption of commercial natural gas (Lei, 2018), and is also an important part of the industrial chain of natural gas production, supply, storage and marketing (Zhang, 2016; Zhang, 2017). In order to make effective and reasonable resources use of UGS, and solve the complex injection and production, scheduling needs brought about by the rapid construction and development of UGS, as well as many challenges such as operation optimization and safe production (Pan, 2016; Wang, 2022; Wang, 2023), the integrated simulation technology for UGS is an urgent need, which could maximize the important role of UGS in seasonal peak regulation and strategic reserve (Liu, 2021; Zhang, 2023). In addition, with the development of digital and intelligent technology (Mi, 2023; Yang, 2021), how to achieve digital and intelligent management and production of UGS (Brown, 2008), is also the key to safe, economic and efficient operation of UGS (Li, 2008; Li, 2012).
For the integrated simulation technology of UGS, it is necessary to establish the integrated high-precision model of reservoir, wellbore and ground process (Wu, 2017; Gao, 2018), with the porous flow of reservoir as the core and the multiphase flow of wellbore and ground as the constraint condition. Many scholars around the world have carried out a lot of research on the integrated mechanism model connection of reservoir, wellbore and ground process. The mechanism model connection of integrated simulation focuses on theoretical research, and has been applied in the UGS and gas reservoir (Liu, 2020). Such as, a three-phase flow model of reservoir, wellbore and pipeline coupling is established for the coupling simulation of horizontal Wells, and an integrated model of coupling reservoir with wellbore and pipeline is established to study the influence of temperature and wellbore volume on pressure drop test (Li, 2021). Besides, the drift flow model is introduced into the reservoir-wellbore-pipeline integrated coupling model (Wang, 2020; Wang, 2021), and the fluid accumulation problem of fractured Wells in tight gas reservoir and the causes of well performance instability are studied by coupling reservoir model with wellbore model (Liu, 2022; Zhu, 2023). The all research above have carried out the mechanism model integration of reservoir-wellbore-ground process.
