The use of horizontal directional drilling (HDD) technology has exploded over the past few years. One reason for this is that hdd drilling allows for efficient installation of pipelines and underground utilities for less labor and environmental disturbance. However, the expansion of the use of this technology has brought with it some unique issues. Thus, guidelines were strictly imposed.

Don’t ever mix “wrong” substances.

Mudmen or mud engineers working at hdd drilling rigs are vigilant about two different things: mixing drilling fluids the “wrong” way, or, doing something that doesn’t work (ex: mixing drill fluid the “wrong” way).

For example, it’s important to start with clean water if you want a stable emulsion when making mud from scratch.

You might also come across the expression “mixing black and brown.” When rig hands use this phrase, they’re referring to mixing drill fluids that aren’t compatible.

For example, mixing water and oil-based muds. When drillers mix these fluids together, they have to add a chemical additive to make the emulsion stable (i.e., prevent it from separating into layers).

Most of the time when rig hands use this expression, they’re referring to making mud by combining fresh water with oil-based drilling fluid. The most common mistake is mixing them in the wrong order or proportions.

Do choose the right tool for the job.

When you’re making mud from scratch or changing out a fluid package, be sure that every component gets into the tank at the same time. Otherwise when you dump it all together, you have a good chance of mixing them with the wrong tools, such as a belt auger or drill pipe. In these situations, always use an internal mixer.

Do check and double-check the mud log before you change out your fluid packages.

If you’re changing out the fluid package on a well that’s already been drilled, it’s important to thoroughly review the mud log before you begin drilling with a new type of fluid. This will allow you to troubleshoot problems caused by using the wrong fluid, or for mixing incompatible fluids together.

Do Use proper equipment when handling oil-based drilling fluids and fresh water.

It’s tempting to use your pressure washer to clean the mud tank after you’ve changed out your drilling fluids. But if you use an oil-based fluid to make the new mud in your tank, you’re at risk of contaminating fresh water tanks or any other equipment with oil residue.

This is especially important to remember when you’re using coiled tubing units, which are more sensitive than wireline units.

Do use caution when you’re using fresh water on oil-based muds.

When fresh water is used to make emulsions, in most cases it’s a good idea to add some kind of chemical stabilizer. However, if the drilling fluid has a high amount of clay in it, it may be best to use water without any type of chemical additive. This is because the clay helps keep everything in solution, and you don’t want to risk knocking it out with too much chemical.

Do add chemicals before you mix your muds together.

When adding chemicals to drilling fluids, always make sure that they’ve been mixed into the fluid before you start adding anything else to your tank. This will help reduce the risk of becoming exposed to any hazardous materials that could be present in the chemical additive.

One exception is if you’re using a mud mixer, which can help incorporate additives into water-based drilling fluids at low temperatures (below 50 degrees F). But otherwise try not to mix any additives into your mud tanks or fluid packages until you’re ready to use them.

Do make sure that all of the mixing equipment is clean before you start making mud from scratch.

If there’s any rust, scale and/or other debris on your mixing screen and blades, it may destroy the stability of your emulsion.

If your drillers use frozen drilling fluid, don’t assume that it’s compatible with fresh water.

Many times rig hands assume that if you’re making mud from scratch using frozen fluid and fresh water, there aren’t any compatibility issues to worry about. But it’s important to take a closer look at the package you’re using before you mix the two together. If your drilling fluid has too much clay in it, freezing it may cause it to separate into layers when you use fresh water—which could be hazardous to both people and equipment on the rig floor.

If there’s any doubt about what type of drilling fluid to use, do seek out the advice of a mudlogger or other experienced service provider.

In many cases, drillers will turn to mudloggers for help when they’re having problems and need to identify what component is causing their issues. But in some instances, even with all of the available resources at your disposal it’s still tough to know if you should switch to a different type of drilling fluid.

If you’re not sure, it’s always best to get help from an experienced service provider who has the expertise needed to understand what you’re dealing with and determine which fluid package would be best for your specific situation.


Do keep (always) a water displacement additive on-hand in case of a spill.

It’s always best to keep a water displacement additive handy on your rig whenever drilling is taking place. These will help get rid of any excess fluid that may have spilled on the floor as well as prevent additional fluids from spilling onto the same area. And if you see a spill immediately after it happens, these additives can help absorb up to about one gallon of fluid per pound of additive.

Do not attempt to clean up fluids with your bare hands – even if they’re non-hazardous – as this could expose you to harmful chemicals which could cause long-term health problems.

If you’ve ever spilled water-based drilling fluid, you know how bad it can be. As soon as there’s a spill, you should immediately call for help and perform the appropriate shutdown procedures required by your company or client.