Mud drilling made easy for oil 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.

WTPP now operates 11 of the pumps across West Texas as a result of the success it has had with the KZN pumps.

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, so extending its life
  • Transporting rock fragments (cuttings) to the surface
  • Preventing the wellbore from caving in before the casing is inserted
  • Stopping the oil or gas from entering the well before it is 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, West Texas Premix Pits (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 10 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 to be reused is pumped out of the other side of the pit.

Specialised baskets

Not surprisingly, moving all of this liquid requires pumps. And, although they are using a conventional pit configuration, WTPP has developed a system for floating the pumps on top of the liquid in the pit. Specialised baskets are built to hold the pumps so they are 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 there is cleaner drilling fluid and that results in faster drilling.”

WTPP needed a supply of heavy duty pumps that could operate 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. The firm was approached by WTPP to recommend an appropriate pump for this 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,” he said. “These pumps handle solids a lot better than most other electric submersible pumps we have seen and they hold up better.”

WTPP installs and maintains the reserve pits used during oil and gas exploration.

Pump performance

The KZN series pumps are designed 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. All wetted parts are constructed of abrasive resistant 28% chrome iron (600 Brinell, 71 Rockwell C) for maximum wear life. Also, a replaceable hardened wear plate is located on the suction side, where erosion would cause a loss of pump performance.

An integral agitator fluidises 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% by weight. Other features include 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; a stainless steel shaft and shaft sleeve that provide maximum wear and corrosion protection and pump volutes cast from hardened ductile iron (300 Brinell hardness).

As a result of the success it has had with the KZN pumps over the past two years, WTPP now operates 11 of the pumps in various oilfield installations across West Texas.