Pumps Handle Drilling Mud in Difficult Situations
The oilfield can be a harsh environment for those working in it and for the equipment that supports their efforts. Rigs are often located in remote areas that may be subject to extreme weather conditions.
And although the rugged terrain may be barren, the site still has to be prepared to accommodate the rig and all required equipment, hundreds of feet of pipe, and one or more pits for drilling mud and other fluids.
Before drilling can begin the site must be cleared and leveled and in some cases access roads need to be built. A source of water is also required, which may mean drilling a water well, and one or more pits are dug and lined.
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.
Ideally and increasingly, this fluid is recycled during drilling. To facilitate reuse, cuttings are allowed to settle out in a pit and the resulting liquid is pumped back to the wellbore.
Water is often a natural by product of the drilling and production process. Water may be trapped underground along with the oil and gas. Sometimes this produced water is incorporated and used in the drilling process.
This simple overview illustrates the fact that drilling a new well is a complicated process with many moving parts – literally. A variety of providers are necessary at different times to deliver their unique services until a well is completed.
Numerous pumps needed
Not surprisingly, moving all of this liquid requires pumps. 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. In West Texas, those challenges often occur in the oilfield. United Rentals was approached by West Texas Premix Pits (WTPP) to help with a solution for a new application.
WTPP manufactures and sells premix pits, trash pumps and safety showers to oil and gas drillers in the Midland-Odessa area. Some of its clients were looking for an efficient solution to pump and recirculate spent drilling mud. Ian Walker, sales representative for United Rentals, recommended BJM Pumps’ KZN series heavy duty submersible pump.
“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.”
Among other things, WTPP installs and maintains reserve pits used during oil exploration. The pits are roughly one acre ponds that hold from two to ten feet of drilling fluid that can 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.
Although using a conventional pit configuration, WTPP is trying something new with its pumps – floating them 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.
“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 initially rented BJM’s KZN series pumps from United Rentals, but after they proved their worth, they decided to buy. “They were great pumps so we stuck with them,” Freeman said.
Although WTPP’s floating configuration has minimized the pumps exposure to solids, the oilfield environment still presents challenges for these pumps, particularly if the water is brine. “Salt water is hard on anything,” Freeman said. “I have customers flush the pump on a regular basis to keep it from getting corroded.”
Although not maintenance free, 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.
All wetted parts are constructed of abrasive resistant 28 percent chrome iron 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. 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.
Mike Bjorkman is vice president and director of marketing with BJM Corp.