How could the drilling mud, especially oil based mud, can give bad
environmental effect?
How could the drilling mud, especially oil based mud, can give bad environmental
effect?

Well, it is known that oil based mud from diesel oil contents high number
of aromatic, but, it will not affect environment if it is not disposed to
environment, will it?

Does drilling mud is diposed to environment, especially in off-shore?

If drilling mud is not disposed to environment, absolutely it will not bring
environmental effect.

But the question is, are we sure this mud undergo special treatment prior
to disposed directly to environment?? We know that drilling mud is not only
containing base fluid (water, oil or gas), barite or bentonite, but it was
containing other chemicals as well. As we know, those chemicals are categorized
as dangerous substances as well as diesel oil or any kind of hydrocarbon
oil.

As long as drilling operation, eventhough we have tried to apply closed system,
mud spill usually happened, and I think mud spills could be categorized as
environmental pollution, depends on volume and the impact. And the real environmental
problem comes up when drilling operation has been finished. If we have a
thousand barrels of waste drilling mud, for sure if we are directly disposed
this mud to env..it will bring bad environtment pollution. But it could be
minimized through mud treatment process.

Oil Based Mud (OBM) will not damaging the environment as long as it stays
inside the well & inside the mud circulation system. OBM must not be
dumped overboard into the water, river, stream, pond, lake, swamp, land,
etc. Most of Water Based Mud is environmental friendly, therefore it can
be dumped overboard safely.