Definition - What does Borehole Fracture mean?
Borehole fractures are the result of a severe difference in the pressure of the drilling mud introduced into a bore and the hydrostatic pressure of the material through which the bore is drilled. Borehole fracture damage occurs in two ways:
- If the pressure of the drilling mud is higher than the hydrostatic pressure of the borehole wall, the mud will be forced into the surrounding material of the borehole wall. Drilling mud may stop circulating.
- If the hydrostatic pressure within the borehole's walls is higher than the pressure of the drilling mud, the same "kick occurrences" that precede blowouts in oilfield drilling will occur, although the damage in trenchless technology is more likely to resemble a collapse of the borehole wall.
Trenchlesspedia explains Borehole Fracture
Borehole fracturing is another form of borehole instability. It happens when the drilling fluid pressure exceeds the pressure at which the boreholes walls or rock formations surrounding the bore fractures (the formation fracture pressure).
When a fractured borehole occurs, you may also find fluid from the rock formation is being pushed into the bore while you're drilling. These are called "kicks." If the situation is not resolved, it may result in a blowout. And, yes, blowouts can happen in any of the drilling disciplines, although those associated with petroleum/oil/gas are more spectacular and deadly.