MENG Wenhui, ZHANG Wen, WANG Boyang, et al. Analysis of characteristics of coal fine production and its influence factors in Baode block[J]. Petroleum Reservoir Evaluation and Development, 2023, 13(4): 441-450. DOI: 10.13809/j.cnki.cn32-1825/te.2023.04.005.
The issue of coal fine production is increasingly prominent in the development of coal-bed methane. Implementing appropriate measures to control the migration and production of coal fines is crucial for achieving stable and high production of coal-bed methane wells. However
the characteristics of coal migration and production in the coal seams of Baode block remain unclear
which hinders the efficient development of coal-bed methane in some wells in this area. To address the problem of coal fine production in coal-bed methane development
core flooding experiments were conducted to investigate the migration and production characteristics of coal fines concerning influencing factors such as formation water velocity
salinity
gas-water ratio
effective stress
etc. The experimental results revealed that during the drainage stage
the amount of coal fines produced at low formation water flow is minimal
with coal fines moving within fractures and accumulating at the outlet
forming a coal powder filter cake. However
when formation water flow surpasses the critical flow
a significant amount of coal fines is produced. A substantial pressure fluctuation can flush out the coal fines obstructing the outlet. Furthermore
the salinity of the formation water plays a role in carrying coal powder
with higher salinity increasing its transport capacity. While single gas phase flow is not effective in displacing the coal fine migration and production
two-phase flow with a gas-water ratio of 50∶50 exhibits a stronger ability to carry coal powder. The concentration of coal fine in the produced liquid continued to decline with the increase of the effective stress loaded on the coal
Similarly
the holding pressure at the outlet follows a downward trend
but the displacement pressure difference increases. The research findings provide essential data and a theoretical basis for implementing on-site prevention and control of coal fine production.