Shale gas & pollution – what goes down the well.

Bentonite dispensing

Dispensing Bentonite into the drilling fluid of a deep drilling operation. Just how environmentally friendly is this?

There are two things that can be said about shale gas and pollution.  The first is that there is a lot of rubbish, some deliberately so, talked about the dangers of drilling for shale gas.  The second is that all, repeat all, activity (and, indeed, all inactivity) has its dangers.  Basically and first of all, the dangers of pollution depend on the mechanics of the drilling operation first and the strata drilled through. Secondly, what gets put down the hole and what is done with what comes out. Over the next few weeks, this blog will be looking at some of the experience – here and overseas.

For starters, what does and does not go down the well at drilling?

Nobody ever puts radioactive material (such as Radon gas) down the well. Not ever, under any circumstances.  Historically and possibly in the USA, oil-based drilling fluids were used.  Here in the UK, the drilling fluids are normally water-based.  Some are even drinkable. Bentonite is often added.  This is a natural clay and you can eat it.  (You would quickly become constipated if you ate much but it isn’t toxic.)

There are other additives that are sometimes added but by no means always.  Sometimes, because of high temperatures, pesticides may be added but, in the UK, these are added under strict controls which demand a high degree of environmental friendliness and lack of persistence. Many thousands of gallons of water are pumped down these wells and that frequently gives rise for concern.  In the UK, there are controls which limit what happens and there is a major concern by the industry to recycle water and new technologies are being developed to help this.

Questions to ask;

  1. What does go down the well and what happens to it down there?
  2. How much water is used and where does it come from?
  3. Is there an independent body monitoring what goes on?

 

Bill Butterworth  3rd January 2016

Next week;  What about leaks from the system?