The Australian Coal Industry’s Research Program (ACARP) has released a CSIRO report on coal seam gas drainage, finding that drilling boreholes can improve drainage.
The report examined the effect that borehole permeability damage could have on gas drainage.
Damage is a problem that limits the permeability of gas drainage boreholes.
“We reviewed the mechanisms and there was some evidence of that damage could occur in gas drainage boreholes,” CSIRO researcher Luke Connel told MINING DAILY.
“The report found that damage does occur and it can have a negative effect on the rate of gas from the boreholes, and then the overall effectiveness of the drainage boreholes.”
The report offered suggestions about drilling designed to decrease damage and potentially create more effective gas drainage.
By drilling the borehole and redistributing the stress around it, the vicinity of the borehole is increased and better drainage is potentially achieved.
In research conducted on underground in-seam boreholes at the West Cliff coal mine in NSW, the report established little evidence of damage was found after the boreholes had been drilled.
The CSIRO researchers hope the report will open people’s eyes about the potential of damage.
People in the industry need to be aware of the potential of damage and the fact that it can greatly reduce the effectiveness of drainage boreholes, and they need to be cautious of contributing to the problem, Connel said.
“It is an important effect and they’ve got to be aware that there are certain things they can do which can increase the damage and limit the effectiveness of the boreholes for draining gas.”