What Are the Three Main Types of Drilling Muds?

Here at AA Turner Tankers, we’re involved in a wide range of liquid waste management activities for commercial and residential customers across Colchester, Essex and Suffolk, as well as parts of East Anglia, Hertfordshire, Cambridgeshire and London.

One of the lesser-known things we do is handle the waste that results from using muds and fluids in drilling activities.

In this article, we’re going to explore the world of drilling muds, including explaining the three main types of drilling muds used, and discover how our tankers help to ensure drilling sites are left free from pollutants afterwards.

An introduction to drilling muds

When drilling deep into the ground – such as for water wells or for oil and gas – drilling muds, also referred to as drilling fluids, need to be pumped into the borehole. These drilling muds carry out a number of important functions, including:

• Suspending rock cuttings and providing hydrostatic pressure – this prevents the cuttings from entering the well itself by bringing them to the surface.
• Stabilising the borehole – by creating an impermeable barrier between the fluid and the surrounding soil or rock.
• Increasing buoyancy – this reduces stress on the surrounding rock brought about by adding heavier pipes to the well as you drill deeper.
• Providing lubrication – to both prolong the lifespan of the drill bit and reduce friction heat.

The result of this is that – as well a freshly-drilled hole in the ground – you should end up with your muds at the surface, mixed together with the materials that have been drilled out.

What are the three main types of drilling muds?

• Water-based drilling muds

The most commonly used type of drilling mud, probably because it is also the cheapest and causes the fewest environmental issues (although it is still likely to contain a few chemical additives to enable some of the uses listed in the previous section). 

Water-based drilling muds are of more use in certain applications – such as looking for oil – because they provide purer information to engineers and geologists studying the samples produced by the drilling. 

• Oil-based drilling muds

Although considerably more expensive and environmentally hazardous, oil-based drilling muds are recommended for certain soil and rock types that are likely to be more sensitive to a water-based solution. This includes shale and high temperature holes that would cause water to evaporate.

Oil-based muds also improve drilling performance by delivering a higher penetration rate and producing a better gauge hole.

• Pneumatic or air drilling muds

When conditions allow, such as when drilling into hard and dry rock formations, using compressed air or nitrogen can be an even cheaper and more environmentally sustainable solution than using water-based muds.

However, if water or oil are encountered during the drilling process, the air is unlikely to be able to bring them to the surface. Air drilling can also cause some boreholes to slough or break apart if the formation isn’t strong enough to withstand the pressure.

Drilling mud waste management

Drilling mud waste management is an important consideration for operators, as they will always have specific environmental responsibilities and legal obligations to fulfil. 

As we have mentioned earlier, the drilling process when using muds results in quantities of waste being brought to the surface. This waste is made up of the muds pumped in to aid the drilling and the rock and soil removed to make way for the borehole. At this point, specialist liquid waste disposal experts are required to collect and take it away – and this is where the team at AA Turner Tankers comes in. 

Our tankers are used to transport the waste under EWC 010504 (absolute non-hazardous) to licensed disposal facilities where it is processed through their treatment plants. This involves separating the muds from the rock cuttings. 

Water-based muds can usually be disposed of, but it is possible for oil-based muds to be reused or recycled. The rock cuttings can also usually be reused and recycled.

If you’d like to know more about how AA Turner Tankers can help with professional and specialised liquid waste management, including the disposal of waste from drilling operations, why not get in touch with our expert team today?