Oil and gas drilling is tough on equipment, particularly the drill bit, which needs almost constant attention to keep the rig operating properly. Injecting drilling mud into the wellbore is among the most important techniques crews have to keep the drill bit and the rest of the operation on track. Drilling mud includes varying combinations of bentonite, barite, fresh- or salt-water, oil or other synthetic additives. This depends on the type of formation you’re drilling and the restrictions imposed by environmental regulations.
For the rig crew, mud offers a lot of benefits, including:
- Cooling and lubricating the drill bit
- Suspending cuttings (the rock, coral, sand, etc. chewed up by the drill bit) and carrying them back to the surface
- Helping to control pressure in the well by offsetting the pressure of the oil or gas being released
- Stabilizing exposed rock
- Providing buoyancy for the hundreds of feet of drill pipe
- Reducing friction with the surrounding rock formation
However, moving spent drilling mud is tough on equipment because it is thick, highly abrasive, and often acidic and corrosive. The pumps used to send the mud into the cellar (an area beneath the drilling rig) and into and out of the reserve pit (where the cuttings are allowed to settle out) take a lot of abuse. They must be durable enough to stand up to the slurries and operate without significant head loss or efficiency loss. Given the enormous costs to operate a drilling rig, crews can’t afford the downtime necessary to replace a malfunctioning pump.
Hard Metal Pumps for High Performance
In the past, drilling rig crews typically used basic cast-iron submersible wastewater pumps to move spent drilling mud. These basic pumps struggle to handle the abrasive slurry. This often led to broken shafts and impeller bolts, failed seals, loosened impeller keyways, and unplanned and expensive downtime. More recently, a growing number of drilling companies are choosing heavy-duty, hard metal agitator slurry pumps instead. These pumps offer the durability necessary for long-term operation in the harsh environment of a drilling operation.
To ensure high wear resistance, you must carefully weigh the advantages of the various pump designs you’re considering. For example, pumps with a top-discharge design allow for greater adaptability to low fluid-level conditions. Look for features that ensure maximum wear and corrosion protection like a stainless steel shaft and shaft sleeve and chrome iron-constructed wetted parts. To prevent the loss of pump performance due to erosion, look for designs with a replaceable hardened wear plate. Ask if the pump volute (the curved funnel that leads to the pump’s discharge port) is made from hardened or standard ductile iron. Check the thickness of the pump walls at the point where pumped slurry enters the discharge; greater thickness here will enhance durability.
BJM Pumps’ KZN Series hard metal slurry pumps, part of our line of submersible sand, sludge and slurry pumps, are among the most popular solutions available for drilling mud transfer. Engineered with wetted parts constructed of abrasive-resistant 28% chrome iron (600 Brinell, 71 Rockwell C), they combine all of the design features outlined above for a high-performance pump. Because the drilling mud has a high level of solids, KZN Series pumps feature an integral agitator. The agitator “fluidizes” settled solids back into a slurry, making them easier to pump with less chance of clogging. The semi-open impeller can handle abrasive solid concentrations as high as 70 percent by weight. These components combine to extend pump life to keep your project running in even the harshest oilfield conditions.
Download our Horizontal Directional Drilling Buyer’s Guide
Horizontal directional drilling (HDD) is another application that relies on spent drilling mud. The key to keeping spent drilling mud from slowing your drilling operations is making sure that you have the right pump for the job. We’ve created a free guide to help you find the right pump for your HDD projects, including real examples showing how our pumps helped customers deal with the same problems you experience every day. Download the Horizontal Directional Drilling Buyer’s Guide for Submersible Pumps now to find the “pump you need, guaranteed.”