Novel Coalbed Methane Reservoir Permeability and Reserve Evaluation Method Based on Flowing Material Balance Equation at Dewatering Stage Considering Permeability Variation
- Authors
- Juntai Shi (China University of Petroleum, Beijing) | Jiayi Wu (China University of Petroleum, Beijing) | Tao Zhang (China University of Petroleum, Beijing; The University of Texas at Austin) | Zheng Sun (China University of Petroleum, Beijing) | Yanran Jia (China University of Petroleum, Beijing) | Yexin Fang (China University of Petroleum, Beijing) | Xiangfang Li (China University of Petroleum, Beijing)
- DOI
- https://doi.org/10.15530/AP-URTEC-2019-198274
- Document ID
- URTEC-198274-MS
- Publisher
- Unconventional Resources Technology Conference
- Source
- SPE/AAPG/SEG Asia Pacific Unconventional Resources Technology Conference, 18-19 November, Brisbane, Australia
- Publication Date
- 2019
- Document Type
- Conference Paper
- Language
- English
- ISBN
- 978-1-61399-673-7
- Copyright
- 2019, Unconventional Resources Technology Conference (URTeC)
- Keywords
- Lattice Boltzmann, Nanopores, Shale matrix, Fluid-loss, Liquid slip effect
- Downloads
- 41 in the last 30 days
- 42 since 2007
- Show more detail
SPE Member Price: | USD 9.50 |
SPE Non-Member Price: | USD 28.00 |
Reserve and formation evaluation are the basis to the development of coalbed methane (CBM) reservoirs. To date, material balance methods and productivity analysis methods are mainly used to estimate the reserve and permeability, respectively. However, there are lack of methods for determining reserve and permeability simultaneously. In this work, the typical characteristics of undersaturated CBM reservoirs during production process, such as permeability variation and expansion effect of immobile gas, are firstly considered to derive a novel flowing material balance equation (FMBE), by which the reserve and permeability can be estimated. Based on the production data at single phase dewatering stage, the control volume and reservoir permeability of the CBM reservoir can be derived by the slope and y-intercept of the fitted straight line. And then the original gas in place (OGIP), initial water reserve, initial adsorbed gas reserve, initial free gas reserve, and initial dissolved gas reserve can be determined. Verification cases show that the errors between the evaluated and actual values are small, regardless of whether there is free gas in CBM reservoirs at the initial condition, indicating that the method is reasonable and accurate. The proposed method has been used in some CBM wells in China. It has been proven to be easy-to-use, time-saving, low-cost, and with high accuracy.
File Size | 1 MB | Number of Pages | 16 |
Pedrosa, O. A., 1986. Pressure Transient Response in Stress-Sensitive Formations. Society of Petroleum Engineers. doi:10.2118/15115-MS