Recommended Practice for Experimental Evaluation of the Seepage Sensitivity Damage of Coalbed Methane Reservoirs

Authors: Hao Liu, Lihui Zheng, Chinedu J. Okere, Chao Wang, Xiangchun Wang, Peng Zhang

Abstract:

The coalbed methane (CBM) extraction industry (an unconventional energy source) has not established guidelines for experimental evaluation of sensitivity damage for coal samples. The existing experimental process of previous researches mainly followed the industry standard for conventional oil and gas reservoirs (CIS). However, the existing evaluation method ignores certain critical differences between CBM reservoirs and conventional reservoirs, which could inevitably result in an inaccurate evaluation of sensitivity damage and, eventually, poor decisions regarding the formulation of formation damage prevention measures. In this study, we propose improved experimental guidelines for evaluating seepage sensitivity damage of CBM reservoirs by leveraging on the shortcomings of the existing methods. The proposed method was established via a theoretical analysis of the main drawbacks of the existing methods and validated through comparative experiments. The results show that the proposed evaluation technique provided reliable experimental results that can better reflect actual reservoir conditions and correctly guide the future development of CBM reservoirs. This study is pioneering the research on the optimization of experimental parameters for efficient exploration and development of CBM reservoirs.

Keywords: Coalbed methane, formation damage, permeability, unconventional energy source.

References:

[1] A. Nick, G. Paul, A. Paul, and S. V. Wagensveld, "Coal Bed Methane - Unconventional Gas Becomes an Optimised Solution." Paper presented at the Abu Dhabi International Petroleum Exhibition & Conference, Abu Dhabi, UAE, November 2016. doi: https://doi.org/10.2118/183360-MS
[2] Y. Song, X. Zhang, and S. Liu, “Status Quo and Research of CBM Exploration and Development. In: Coalbed Methane in China”, Springer, Singapore, 2021. https://doi.org/10.1007/978-981-33-4725-0_1
[3] J. Huang, S. Liu, S. Tang, S. Shi, and C. Wang, “Study on the Coalbed Methane Development under High In Situ Stress, Large Buried Depth, and Low Permeability Reservoir in the Libi Block, Qinshui Basin, China”, Advances in Civil Engineering, 2020. doi:10.1155/2020/6663496
[4] J. He, C. J. Okere, G. Su, P. Hu, L. Zhang, W. Xiong, and Z. Li, “Formation damage mitigation mechanism for coalbed methane wells via refracturing with fuzzy-ball fluid as temporary blocking agents”, Journal of Natural Gas Science and Engineering, Vol. 90,2021. https://doi.org/10.1016/j.jngse.2021.103956
[5] C. J. Okere, G. Su, L. Zheng, Y. Cai, Z. Li, and H. Liu, “Experimental, algorithmic, and theoretical analyses for selecting an optimal laboratory method to evaluate working fluid damage in coal bed methane reservoirs”, Fuel, 2020, 118513. DOI: 10.1016/j.fuel.2020.118513
[6] H. Liu, S. Sang, J. Xue, T. Lan, H. Xu, B. Ren, and Q. Cheng, “Experimental study on the velocity sensitivity of coal reservoir during coalbed methane drainage in southern Qinshui Basin”, Energy Exploration & Exploitation, 36(6), 2018, 1593–1608. https://doi.org/10.1177/0144598718766091
[7] Y. Yang, X. Peng, and X. Liu, “The Stress Sensitivity of Coal Bed Methane Wells and Impact on Production”, Procedia Engineering, Vol. 31,2012, Pp. 571-579. https://doi.org/10.1016/j.proeng.2012.01.1069.
[8] B. Wang, Y. Qin, J. Shen, G. Wang, Q. Zhang, and M. Liu, “Experimental study on water sensitivity and salt sensitivity of lignite reservoir under different pH”, Journal of Petroleum Science and Engineering, Vol. 172,2019, Pp. 1202-1214. https://doi.org/10.1016/j.petrol.2018.09.036.
[9] Y. Lin, Y. Qin, D. Ma, and J. Zhao, “Experimental Research on Dynamic Variation of Permeability and Porosity of Low-Rank Inert-Rich Coal Under Stresses”, ACS Omega, 2020;5(43):28124-28135. Published 2020 Oct 21. doi:10.1021/acsomega.0c03774
[10] F. Quan, C. Wei, S. Feng, and Y. Hu, “Physical Experiment and Numerical Simulation of the Depressurization Rate for Coalbed Methane Production”, ACS Omega, 2020;5(35):22661-22673. Published 2020 Aug 24. doi:10.1021/acsomega.0c03439.
[11] B. Wang, F. Sun, D. Tang, Y. Zhao, Z. Song, and Y. Tao, “Hydrological control rule on coalbed methane enrichment and high yield in FZ Block of Qinshui Basin”, Fuel, Volume 140,2015, Pages 568-577, https://doi.org/10.1016/j.fuel.2014.09.111.
[12] A. M. Shar, A. A. Mahesar, A. D. Chandio, et al., “Impact of confining stress on permeability of tight gas sands: an experimental study. J Petrol Explor Prod Technol 7, 717–726 2017. https://doi.org/10.1007/s13202-016-0296-9.
[13] L. Yongshou, Y. Xiangyi, L. Yuan, and Z. Hua, “Exploration of a new method on velocity sensitivity test for coalbed methane(J)”, Petroleum Geology and Engineering, 24(5), 2010, 132-133.
[14] M. Zhaoping, H. Anqi, Z. Peng, H. Haijin, and W. Jie, “Experimental study on flow rate sensitivity of coal in typical coal mining area of Qinshui Basin and its control mechanism(J)”, Journal of China Coal Society, 42(10), 2017, 2649-2656.
[15] L. Lin, K. Yili, C. Yijian, Y. Jian, L. Qiangui, H. Yongdong, et al., “Discussion on evaluation methods for stress sensitivities of low permeability and tight sandstone reservoirs(J)”, Drilling Fluid & Completion Fluid, 22(3), 2005, 1-4.
[16] Y. Liyou, G. Shusheng, X. Wei, et al., “Percolation characteristics of gas in sandstone gas reservoir with low permeability under reservoir pressure(J)”, Complex Hydrocarbon Reservoirs, 2011, 4(1):59-62.
[17] Y. Lijun, X. Kunlin, K. Yili, et al., “Pore structure and limit pressure of gas slippage effect in tight sandstone(J)”, The Scientific World Journal, 20132013:572140.
[18] Y. Lijun, C. Yang, K. Yili, Y. Xiaopeng, and W. Yijun. “Productivity index method for experimental evaluation of working fluid damage in low permeability gas reservoir (J)”, Drilling Fluid & Completion Fluid, 2020, 37(5):620-625.
[19] C.J. Okere, G. Su, X. Gu, B. Han, and C. Tan. “An integrated numerical visualization teaching approach for an undergraduate course, Flow in Porous Media: An attempt toward sustainable engineering education”. Computer Applications in Engineering Education, 2021. https://doi.org/10.1002/cae.22426