West Texas Premix Pits (WTPP) is a Midland-based surface rental company that manufactures and sells premix pits, trash pumps and safety showers to oil and gas drillers in the Midland–Odessa area. Recently, some of WTPP’s clients were looking for an efficient solution for recirculating and reusing the drilling mud necessary for drilling new wells.
Fluids play an integral role in oil and gas exploration and production. When a new well is drilled, some form of fluid is needed. The base of this drilling fluid, or mud, can be freshwater or saltwater (brine) or it may be an oil- or synthetic-based liquid. The type of fluid and the additives used are determined in part based on the composition of the rock being drilled into. Cost and environmental impact are also considerations. The mud may also be modified as drilling progresses and the underground environment changes. The mud serves a number of important functions:
- lubricating and cooling the drill bit, thereby extending its life
- transporting rock fragments (cuttings) to the surface,
- preventing the wellbore from caving in before the casing is inserted, and
- preventing the oil or gas from entering the well before it’s completed.
Ideally and increasingly, this fluid is recycled during drilling. To facilitate reuse, cuttings are allowed to settle out in a reserve pit and the remaining liquid is pumped back to the wellbore.
As part of its services, WTPP installs and maintains the reserve pits used during oil and gas exploration. The pits are roughly one-acre ponds that hold from two to ten feet of drilling fluid that may be from brine or freshwater. The mud coming up out of the hole with the cuttings is deposited into one side of the pit and allowed to settle out, and the fluid that’s reused is pumped out of the other side of the pit.
Not surprisingly, moving all of this liquid requires pumps. And, although they are using a conventional pit configuration, WTPP is has developed a system for floating the pumps on top of the liquid in the pit. WTPP builds specialized baskets to hold the pumps so they’re sitting in just six to eight inches of water at the end of the pit away from where the cuttings settle.
“It helps the drilling rig pick up cleaner fluid because the pumps are taking fluid off the top,” said Danny Freeman, owner of WTPP. “As the stuff settles out they have cleaner drilling fluid, and that results in faster drilling.”
WTPP needed a supply of heavy duty pumps that could operate in reliably under varying conditions and without needing to be completely submerged.
United Rentals – Pump Solutions is a large equipment rental provider with dedicated experts who work with operators and other service providers to find solutions for a variety of challenges. United Rentals was approached by WTPP to recommend a pump appropriate for this new application.
Ian Walker, United Rental sales representative, recommended BJM Pumps KZN series heavy duty submersible pump for the WTPP application.
“We really like the durability of BJM in the oilfield,” Walker said. “These pumps handle a lot of solids a lot better than most other electric submersible pumps we’ve seen and they hold up better.”
The KZN series pumps are rugged enough to provide reliable long-term operation in even the harshest of drilling environments, including those where the pumps have to handle a greater percentage of solids. Some of the characteristics that set the KZN series apart from other pumps are:
Optimum Wear Resistance
All wetted parts are constructed of abrasive resistant 28 percent chrome iron (600 Brinell, 71 Rockwell C) for maximum wear life. In addition, a replaceable hardened wear plate is located on the suction side, where erosion would cause a loss of pump performance.
Maximum Solids Handling Capability
An integral agitator fluidizes settled solids into a slurry making them easier to pump with less chance of clogging. The semi-open impeller handles abrasive solid concentrations as high as 70 percent by weight.
Other factors that make the KZN Series pumps ideal for challenging environments are:
- Class H motor insulation and built in amperage ( FLA ) and temperature overload protection;
- Double silicon carbide mechanical seals in a separate oil filled seal chamber;
- Heavy duty lip seal that provides additional protection for the mechanical seals;
- Stainless steel shaft and shaft sleeve that provide maximum wear and corrosion protection;
- Pump volutes cast from hardened ductile iron (300 Brinell hardness), which is twice as abrasive resistant as standard ductile iron with walls that are extra thick at the point where pumped slurry enters the discharge.
(Specifications may differ among models.)
As a result of the success they’ve had with the KZN pumps over the past two years, WTPP now operates 11 of the pumps in various oilfield installations across West Texas.
“We’ve been very pleasantly surprised with the durability and reliability of them,” Freeman said. “They were a great pump so we stuck with them.”