Numerical Simulation Research on Improvement Effect of Ultrasonic Waves on Seepage Characteristics of Coalbed Methane Reservoir

Energies

Cuinan Li¹  Ben Li²  Yundong Zheng³  Rongxin Li⁴  Yao Wang⁴  Jie Zhang⁴  Changjun Wu⁴  Zaipeng Zhao⁴  Tianyu Hong⁴  Qi Qi⁴  Xin Li⁴  Xiaoxiao Du⁴  Xu Liu⁴ 

[1] Engineering Technology Research Institute, CNPC Southwest Oil & Gasfield Company, Guanghan 618300, China;Exploration and Development Division, CNPC Huabei Oil field Company, Renqiu 062550, China;Exploration and Development Division, CNPC Southwest Oil & Gasfield Company, Chengdu 610066, China;State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Southwest Petroleum University, Chengdu 610500, China;

关键词: CBM reservoir;    ultrasonic waves;    seepage;    numerical simulation;    production;   

DOI  :  10.3390/en14154605

来源: DOAJ

【 摘 要 】

The matrix pores of a coalbed methane (CBM) reservoir are mostly nanoscale pores, with tiny pore throats and poor connectivity, which belong to the category of low–permeability gas reservoirs. The matrix particles and organic pore surfaces adsorb a large amount of CBM. These problems are the main reasons that limit the increase in CBM production. At present, the primary measure to increase CBM production is hydraulic fracturing. However, due to the technical characteristics and geological conditions of CBM reservoirs, applying this technology to CBM exploitation still has some key issues that need to be resolved. Therefore, it is essential to develop a new technology that can effectively increase the production of CBM. This paper proposed a method that uses ultrasonic waves to improve the seepage characteristics of CBM reservoir and theoretically verifies the feasibility of this idea using numerical simulation. In this paper, we firstly coupled the temperature, pressure, and seepage parameters of the CBM reservoir and built a CBM seepage model under the action of ultrasonic waves. Secondly, by comparing the numerical simulation results with the experiment, we verified the accuracy of the model. Finally, on the basis of the mathematical model, we simulated the change characteristics of pore pressure, reservoir temperature, permeability, and porosity under the action of ultrasonic waves. Research results show that under the action of ultrasonic waves, the pressure-drop funnel of CBM reservoir becomes more apparent. The boundary affected by the pressure drop also increases. With the increase of the action time of ultrasonic waves, the temperature of CBM reservoir also increases, and the action distance is about 4 m. With decreased pore pressure, the permeability and porosity of CBM reservoir significantly increase under the action of ultrasonic waves. With increased ultrasonic power, its effect on reservoir permeability and porosity becomes more significant.

【 授权许可】

Unknown