Transient wellbore temperature and pressure calculation model for supercritical CO₂ jet fracturing

ABSTRACT

Supercritical carbon dioxide (SC-CO₂) jet fracturing is a new technology, and it has many significant advantages compared with hydraulic fracturing. Ensuring the CO₂ at supercritical state at the jet point is the key to the effective implementation of this technology. Therefore, this research proposes a numerical model to predict the jet point CO₂ temperature and pressure for SC-CO₂ jet fracturing. In this model, the effect of the tubing, casing, and cement sheath on heat transfer are all taken into consideration; the heat transfer is considered to be transient. The numerical results show that under the condition of high tubing injection rate, increase injection temperature and annulus injection rate both are not effective ways to make sure the CO₂ temperature at the jet point exceeds its critical value. Therefore, in order to keep the CO₂ at the jet point remains in a supercritical state, the tubing injection rate needs to be optimized. The CO₂ pressure at the jet point is always exceeded its critical value during the process of supercritical carbon dioxide jet fracturing.

KEYWORDS:

• Supercritical carbon dioxide
• transient
• jet fracturing
• temperature
• pressure

Additional information

Funding

This work was supported by the the National Science and Technology Major Project of China [2016ZX05044-004-002];the National Science and Technology Major Project of China [2017ZX05064-003].

Notes on contributors

Liang-Ping Yi

Liang-Ping Yi is a doctoral candidate from Southwest Petroleum University with a research interest in supercritical carbon dioxide fracturing. He holds a master’s degree from Southwest Petroleum University.

Min Jia

Min Jia is a doctoral candidate from Southwest Petroleum University with a research interest in heat transfer and mass transfer. She holds a master’s degree from University of Science & Technology Beijing.

Xiao-Gang Li

Xiao-Gang Li is a professor from Southwest Petroleum University with a research interest oil & gas reservoir stimulation mechanic and engineering technology.He holds a PhD from Southwest Petroleum University.

Zhao-Zhong Yang

Zhao-Zhong Yang is a professor from Southwest Petroleum University with a research interest in oil & gas reservoir stimulation mechanic and engineering technology. He is an academic and technical leaders of Sichuan province. He holds a PhD from Southwest Petroleum University.