When drilling into reactive strata where fracking inhibition is a major problem, polymer drilling fluid, also known as polymer fluid, is employed. Salts, glycols, and amines—commonly used fracking inhibitors—are incompatible with bentonite.
Potassium chloride is a cheap and potent shale inhibitor frequently employed as the foundation for polymer drilling fluids. To increase its inhibitory effects, you can add glycol- and amine-based blockers to a drilling fluid.
High-quality drilling fluids are required to ensure the opener runs as efficiently as possible. Water serves as the drilling fluid’s carrier fluid, and bentonite and polymers are its additives. For HDD applications, drilling fluids premised on bentonite are among the most popular. When combined with water, the naturally present clay mineral bentonite (montmorillonite) turns into mud. Therefore, natural sodium bentonite is used to make the highest-performing drilling fluids.
The following are the primary purposes of HDD drilling fluids:
Consider the following factors:
A fluid’s viscosity indicates how difficult it is to move through a given medium. Therefore, for HDD drilling to be successful, the proper flow must always be maintained.
The drilling fluid’s gel strength determines its capacity to support, suspend, and transport cuttings. If the cuttings are not adequately suspended, they will quickly gather around the drill pipe or product line being drawn. This might result in a lack of circulation, a rise of pressure, a “frac out,” and the potential loss of the instrument.
The amount of filtrate (free water) that escapes from the drilling fluid and enters a porous permeable deposit is known as fluid loss. Excellent drilling fluids have a low fluid loss, which is essential for maintaining the integrity of a borehole. A suitable drilling fluid should produce a delicate filter cake on the borehole’s sites. As a result, there is less fluid loss throughout into formation.
The pH scale, with 7 denoting neutrality, expresses how acidic or alkaline a solution is. Drilling fluids must be kept at the proper pH to achieve maximum performance. pH must be kept between 8 and 9 in HDD projects. The easiest way to increase pH is with soda ash.
It is typically encouraged to use a drilling fluid with a bentonite base for most drilling operations. When it comes to perfect qualities, such fluids satisfy all the requirements. However, there are situations when contractors could decide against using bentonite.
Businesses need to match the appropriate drilling fluid solution to the application. This is particularly true for HDD bores with small diameters and short lengths. By using a polymer-based solution, crews can reduce mixing and cleanup time. Although experts advise against using only water in such applications, contractors frequently choose to do so. Unfortunately, this accelerates the wear on boring rods and tools. Additionally, using only water dramatically increases the risk of accidental returns, pipe straining, and getting trapped. This will eventually lead to slower production speeds and unquestionably more significant costs.
The hurry to build new gas, fiber, and electrical networks following the pandemic has raised awareness of polymer-based systems, which often use single-use packaging.
These systems are well-liked by contractors who drill small-diameter, shallow bores for the reasons listed below:
Some drilling fluid combinations may include several components, similar to bentonite systems. The efficiency of the entire mix is impacted by the order that the polymers are added to the mix tank. Assess the state of the ground first. The polymers required to finish the drilling will depend on this. Once you have decided which goods to use and in what sequence to mix them, read the manufacturer’s instructions. Dosing is made simple and fast using single-use packets or jugs.
Small-diameter utility drilling operations will rise more as infrastructure spending rises. This will increase demand for fluids that are simple to use, including polymer drilling fluid systems. Instead of only pumping water, introducing a polymer drilling fluid will boost output and decrease downtime, enabling contractors to maximize revenue.
Many people operating horizontal directional drills have heard a tale or two about someone who finished a large bore while drilling without water or using only water. Even if those tales are true, being boring in this way can have many adverse effects. Drilling dry or only with water can slow down productivity, increase the chance that a bore will fail, and hasten tool wear.
When appropriate, drilling fluid or mud ought to be utilized to maximize the effectiveness of an HDD team. It assists in lubricating, cooling, and flushing drill cuttings, as well as maintaining the integrity of the boring route, downhole tooling, and electronics. The ideal solution is polymer drilling fluids for HDD bores with small diameters.
Here are some of the enlisted problems you could run across without using mud:
Drilling dry
Short, small-diameter bores can be executed without using any fluid in optimal ground conditions. Even under these circumstances, however, slowing output rates and rotational speeds are usually necessary while drilling dry. Additionally, a lot greater friction downhole can lead to tooling overheating. The additional heat may harm the drill blade and sonde.
The drilling heads and drill pipe may prematurely deteriorate over time due to a shortage of drilling fluid. Additionally, it could impose undue strain on the object being pulled back. However, in optimum soil conditions, a little quantity of drilling fluid can go a long way toward maintaining production rates and assisting contractors in maximizing the life of their tools.
Use water
Contractors will often drill without bentonite or polymer and run water through the drill string, which is probably more frequent than drilling dry. There may be hazards associated with this strategy, but it is still preferable to do nothing at all. In clay loam clay soils, which are far more merciful, crews could get away with drilling a pilot hole and then drawing back small-diameter goods. In addition, the danger of collapsing holes can be reduced by using a hydraulic fluid with the appropriate addition.
The drill heads and drill rods have higher drag and resistance because water provides very little lubrication. Therefore, adding some chemicals to the water can prevent premature tool wear.
Additionally, water loses the viscosity necessary to preserve the integrity of the borehole or to float drill bits out of it.
Mix it up
Drilling fluid has a lot of advantages, but it needs to be correctly mixed to take advantage of the chemicals to their fullest extent. Whether contractors purchase bentonite in bags or have switched to liquid drilling chemicals in pouches, a mixing system is essential. You can tell if an addition needs to be combined correctly with powders. However, some individuals mistakenly believe they can pour the newest prepared liquid concentrate additives into the water tank with slight shaking. Therefore, your fluids must be mixed and tested correctly for the best outcomes.
Brands provide many mix systems that are the right size for the horizontal drill your crew operates to aid in the mixing procedure. In addition, to reduce the time required to fill fluid tanks, some mixing systems incorporate characteristics such as a revised, slim rectangular contour tank and a power supply unit that can be coupled with a maximum of two tanks at once.
Drilling fluids to drill as effectively as possible while getting the best performance out of your downhole tooling. Additionally, if you need assistance, instruct your staff on correctly mixing drilling fluids.
Conclusion
Drilling muds with additional polymers allows for the whole substitution of clay with polymer while drilling into water-sensitive shales and liquid zones. Polymers can perform extensive functions: surfactants, deflocculants, foaming agents, corrosion inhibitors, lubricants, filtration control agents, viscosifiers, etc. Drilling fluids often contain organic polymers like starches and guar gum created by natural processes in a laboratory setting and are considered “naturally occurring.” Therefore, they are safe and more suitable for HDD bores with small diameters.
