Research and application of dual tube gas lift technology in coal bed methane well

ABSTRACT

Coal bed methane (CBM) is a gas resource associated with and symbiotic with coal, which refers to the hydrocarbon gas stored in the coal seam, with methane as the main component, which belongs to unconventional natural gas. The development and utilization of CBM has the effect of achieving multiple things in one fell swoop: clean energy, commercialization can produce huge economic benefits. At present, rod pump, screw pump and other lifting technologies commonly used in CBM drainage and production have poor adaptability, short pump inspection period, and it is difficult to enter horizontal section in horizontal well. Aiming at this problem, a new method of efficient CBM lifting is proposed by adopting dual-pipe gas lift technology. In this paper, the basic principle of double tube gas lift is analyzed, the optimization design of gas injection volume, coiled tubing size and coiled tubing running depth is carried out, and the field technology application of vertical and horizontal Wells is carried out. The results show that the dual tube gas lift technology has good adaptability in the deliquification of CBM, and the field application has achieved good production results. After the process modification, gas production of CBM Wells increases continuously, while water production decreases gradually, with the maximum gas rate exceeding 2400 m³/d. According to the latest production data, well L31 has been in steady production for more than 9 months, with an average gas rate of 1294.56 m³/d, which greatly exceeds the capacity before the transformation. Because there are no moving parts in the wellbore, the pump inspection period is greatly improved, and it has the potential to be widely applied in CBM.

KEYWORDS:

• Coal bed methane
• Dual tube gas lift
• Coiled tubing
• Deliquification, optimization method

Acknowledgements

The authors of this article would like to the Research on the Production Technology of Liquid Horizontal Wells in Tight Gas Reservoirs (2022-11316) of Changqing Oilfield Branch of China National Petroleum Corporation.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Notes on contributors

Shunan He

Shunan He graduated from Xi ‘an Shiyou University with a master’s degree. He is now working in No. 2 Gas Production Plant PetroChina Changqing Oilfield Company. His current research focuses on multiphase flow.

Yongsheng An

Yongsheng An is a Associate Professor in China University of Petroleum (Beijing) (CUPB). He received his Ph.D. degree in oil and gas field Development Engineering from the CUPB in 2008. His research interests focused on artificial lift and gas production.

Hui Liu

Hui Liu received his master’s degree in oil and gas well engineering from Southwest Petroleum University in 2013. He is now working in No. 2 Gas Production Plant PetroChina Changqing Oilfield Company. His current research focuses on gas production technology.

Quanwei Yang

Quanwei Yang graduated from China University of Geosciences (Beijing) in 2011. He is now working in No. 2 Gas Production Plant PetroChina Changqing Oilfield Company. His current research focuses on gas production technology.

Guojia Cao

Guojia Cao graduated from China University of Petroleum (Beijing). He is now working in No. 2 Gas Production Plant PetroChina Changqing Oilfield Company. His current research focuses on multiphase flow.

Yangfeng Sun

Yangfeng Sun graduated from China University of Petroleum (Beijing) in 2021. Now he is studying for a master’s degree at China University of Petroleum (Beijing). His current research focuses on (1) Wellbore lift and multiphase flow; (2) gas production.