Working with high-pressure water and vacuum on drilling rigs requires a balance of technical know-how and safety training.

The gas and oil industries were early adopters of hydroexcavation technology as a non-destructive method of uncovering buried infrastructure. High-powered machines are serving a need on land-based drill rigs, assisting in the logistics of moving and recycling oil-based drilling mud.

T-Rex Services, headquartered in Houston, has served the gas and oil industry in upstream, midstream and downstream applications since 2001. With additional offices in Dallas, San Antonio and West Texas, the company now provides hydroexcavation and vacuum excavation services to an array of markets, from industrial construction to municipal and utility contracts to grease trap cleaning. Refineries, oilfields and shale plays, however, still provide the bulk of their work, which can range from locating services to potholing and tank cleaning.

"Hydroexcavation is often required by plant or pipeline owners because it is the safest way to excavate," says Tim Carmichael, president of T-Rex. "There's simply too much at risk in an oil refinery, for example, to leave underground line location to chance. We have master service agreements with most of the major players in the oil and gas industry, and often work as a subcontractor to other service providers. We might be working for oil rig owners, drilling companies, pipeline contractors or engineering firms."

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Much of the refinery work is handled from the company's Houston office. "This is refining country," says Carmichael. "Name a plant and we've probably worked in it." On the other hand, much of the shale work is handled from the company's West Texas office. The regional nature of the project mix helps to develop specialties at each location.


The company workhorse is the GapVax HV-56 with a 5,300 cfm blower, 28 Hg of vacuum and water jet pressure of 1,000 to 3,000 psi. It also features a 17-cubic-yard payload and steel collector body. The company offers more than 25 of the units to serve clients. A single air-excavation VACMASTERS rig rounds out the truck list.

"Only the massive 5,300 cfm positive displacement blowers will do for the tough jobs we put that equipment through," says Carmichael. "On the drill rigs, these units are simply known as 'supersuckers.' We're cleaning out that thick, heavy oil-based drilling mud and mud-soaked drill cuttings and that's the only way you'll move them efficiently. Water-based mud doesn't provide near the same challenge."

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The oil and shale production work isn't offered by contract. T-Rex is almost on call 24/7 for much of the drill rig work, ready to head out anywhere from the Permian Basin to the Eagle Ford Shale or Louisiana's Haynesville Shale. "Generally we're going wherever they're directing us to go and whenever they're ready for us," says Carmichael.


The work of the hydroexcavators at a drilling rig is simply to arrive and to remove drilling mud and cuttings under instruction of the client. In some cases the oil-based mud is transferred to the company's 130-barrel mobile tanker for delivery and recycling according to the client's instructions. In other cases, the mud may be removed from one tank and ejected via sludge pump into reserve pits or other vessels.

"This process can range from an 18-hour stint to days at a time, depending on agitation to the tanks that is performed to keep the mud from forming," says Brad Davis, director of sales and business development with T-Rex. "At the end of the process, T-Rex will go to the disposal to clean any additional mud left in the truck and make sure the truck is free of any oil-based residue that can cause environmental concerns. However, even though we may take the mud to a disposal site, we aren't a disposal service—we're working under the direction of someone who has a contract with a disposal site. Our expertise here is the logistics of working with the oil-based mud."

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The heavy-duty work takes its toll on the vehicles. T-Rex employs eight mechanics who perform preventive maintenance and keep the vehicles in shape after a work day.

"These aren't just 18-wheelers rolling along from job to job," says Carmichael. "The drilling fields represent a challenging mechanical environment. Running a diesel engine, a hydraulic system and a vacuum system through all that mud and adding a significant amount of vibration is a recipe that calls for
frequent maintenance."


Each truck is operated by a two-person crew, that may expand to three if the truck is operating remotely and flex hoses or piping are required to complete the job. Employee selection and training is a key factor in the company's success.

New hires are first subject to a background check. The initial training regimen requires three weeks of intensive education and safety indoctrination. The company employs in-house trainers, as well as three full-time safety staff.

"After training, they're apprenticed with our veteran operators who go out in the field with them until they learn the ropes," says Carmichael.

Ongoing training keeps technical knowledge and safe work habits top-of-mind.

Ultimately, the success of T-Rex's enterprise represents a careful balance between human and equipment resources.

"As a company serving diverse markets, you're balancing your fleet and staff between clients who have different schedules and needs," says Carmichael. "You can't pull yourself off one project to work on another, so you always have to maximize your coverage according to a tight schedule. A lot of companies in this business have from two to five trucks. At our size, we employ five salespeople and two human resources professionals full time. With that support, we can offer service over a wide area, but we also need to keep the fleet busy to justify it, and maintain a trained staff ready to work those contracts."


Safety consciousness must be top-of-mind when operating hydroexcavation equipment. This top 10 list of hydroexcavation safety tips was taken from the safety and policy manuals of T-Rex Services.

Complete all appropriate training.

From safety training to equipment training to job site training, all employees must be kept up to date with current regulations and best practices.

Use a spotter.

All employees must use a spotter, not only when backing up, but also when moving in tight areas, when dumping, or when working in areas containing people and equipment. Use a spotter not just for ground hazards but overhead hazards as well.

Inspect your truck.

Complete a visual pre-trip inspection to verify hazards or problems with hydroexcavation equipment before operating. This is mandatory under Texas Department of Transportation rules and regulations, but should also be mandatory according to company policy.

Drive safely.

Hydroexcavators spend much of their working time off-road. When drivers take the equipment on highways, they need to drive safely, attentively and defensively. Drivers need to learn how the truck will handle differently under any load and adjust their driving accordingly.

Wear Personal Protective Equipment (PPE).

PPE protects employees from the majority of hazards they might encounter. Wear hardhats, steel-toed boots, gloves, safety glasses, reflective vests, face shields for flying debris and earplugs. Wear flame-resistant clothing and slicker suits per site requirements or as required.

Complete confined space training.

This is essential training for hydroexcavation or for oil rig tank cleaning. Employees must learn to recognize and define a confined space, and how to protect themselves from its hazards, including hydrogen sulfide.

Perform a Job Safety Analysis (JSA).

Fill out a JSA form before initiating any job. It helps define the scope of work to be completed and identify and mitigate hazards on the job site through engineering and the use of additional PPE. JSAs should be revised when the scope of the job changes, and all employees must sign the JSA acknowledging they are aware of these changes.

Dump spoils on level ground.

Make sure a hydro truck is parked on level ground before attempting to dump the spoils. Failure to do this could result in the operator flipping the truck over causing injury or death.

Ground out the truck.

The operator should ground out a truck whenever possible. This will not only help protect employees if a truck comes in contact with an electric power source, but will also prevent explosions of contaminated hydroexcavated material producing explosive particles or vapors.

Communicate effectively.

Communication is the key to completing all work safely. In noisy environments, or where verbal communication is not feasible, the use of hand signals is vital to moving the truck and the boom.

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