Bore Planning Made Easier

Intuitive and user-friendly software helps progressive contractors take the guesswork out of planning horizontal directional drilling projects

Bore Planning Made Easier

Horizontal directional drilling (HDD) is challenging and difficult work fraught with unknown obstacles. While it’s not possible to eliminate every obstacle, bore planning software developed by drill manufacturers can help small and large contractors create a bore plan that minimizes risks.

Bore planning software was introduced 15 years ago. However, those basic programs helped contractors design only the pilot bore. While the software helped streamline the planning process, it was time-consuming and not widely used. Many contractors would just drill and hope for the best.

Today, bore planning software packages are more intuitive and user-friendly. The time to create a bore plan has shrunk dramatically, and the programs provide more information than ever about the bore and pullback. The software helps remove guesswork in determining elevations, and in estimating the drill pitch for the pilot bore, the mud volume required, and how hard the pipe will pull.

Much simpler

“These days, a contractor simply needs to gather the topographical elevations and required depth along the bore path, enter the data and hit Plan,” says Curt Dubbin, a trenchless solutions specialist with Vermeer Corp. “The software will then produce a rod-by-rod plan of your bore.”

In the past, it seemed software tools were used only on the larger pipeline bores. That is changing as more contractors working on projects in the mid-sized range – 24,000 pounds and up – begin to use the tools for on-grade and profile bores.

Another reason for the increased popularity is the need to avoid existing underground facilities. “Bore planning tools can be used to help contractors develop a bore plan that will maintain proper separation distances between underground facilities,” says Dubbin.

“This is becoming ever so important as the vast amount of underground infrastructure continues to grow. Many of the software applications also allow users to create a permanent record of the completed bore that can be used as a reference to help generate more accurate bids on future jobs.”

Varied roles

There are a number of bore planning programs on the market, and each has a definite role in the planning process. Here is a quick summary of tools available to HDD contractors:

Analysis. Software programs can help contractors and engineers determine whether open-cut trenching or HDD is appropriate for the installation. Nine aspects are considered, including customer expectations, contractor’s familiarity with technologies, project location, soil sample reports, competitors and risk factors. The software provides a detailed analysis and various considerations for choosing either method and explains the recommendation.

Pre-planning. These tools help contractors select the appropriate drill and tooling based on the type of pipe to be installed and the anticipated soil conditions. Contractors can use a pulling load calculator to estimate the required pulling load for a specific HDD project based on the type of pipe, pipe diameter and total bore length. The calculator also recommends the appropriate drill size based on the bore specification entered for the project.

A soil classification guide helps contractors determine the site’s soil type and match the appropriate drill bit and backreamer. It also includes a fluid-mixing process map that shows how much mud should be used based on soil conditions, drill unit and tooling used.

Terrain mapping. This software is used in the survey phase where laser systems collect accurate topography and information about existing utilities along the bore route. In most applications, the information can easily be uploaded to the bore planning software.

Bore planning software. Using the data collected in the mapping phase, these programs provide a graphic visualization of the job, helping a crew see and perform the job from start to finish. By choosing drill stem diameter and length, the desired bore path depth, the desired minimum cover, and the diameter and allowable bend radius of the product pipe, the software plots a proposed bore path. The path is provided in two formats, one screen showing a top and side view, the other showing a report that lists the numerical depth and pitch of each drill stem.

Once the bore is completed, the actual as-built depths can be entered into the designed profile and a comparison of design versus actual can be graphically shown.

In-field calculations. Any contractor knows things can change once they’re in the field, and a number of drill manufacturers also offer handheld software tools just for those situations. These PDA devices can calculate setback distances, figure point-to-point bore paths, estimate pullback time and hole volumes, and configure the outside diameters of multiple ducts.

Changes on the horizon

While bore planning software has advanced by leaps and bounds in the past five years, manufacturers are constantly looking for ways to enhance their software packages. The trend is heading to more information.

“We are working to tie all of these applications into one complete package,” says Dubbin. “This will provide contractors with more in-depth information and data on proposed and completed bores. The software program will record everything from how hard the drill is working on a bore, to the mud pressures, to the amount of fuel consumed. A contractor will know exactly what happened on the bore, and know the cost.”

With that kind of data on a project, contractors can increase their knowledge base and more accurately bid projects and manage their businesses. The integration will also make the planning process easier. Rather than jumping from one program to the next and then trying to bring it all back together into a cohesive piece, everything will be available in one place.

“Typically, contractors record data on only larger bores, but just imagine the competitive advantage a small to mid-sized contractor could have with this type of information,” says Dubbin. “It could make a significant impact on their business.”

Not just for contractors

While HDD contractors routinely use bore planning software, engineers are also getting on board. “I receive calls every week from engineers asking about our software programs,” Dubbin says. “They are using these tools to better plan underground installation projects that take into account a directional drill’s capabilities.”

The software will help engineers limit the risk of designing directional drill projects that are not mechanically feasible. For example, a plan based on too little data may call for a bend radius that is not possible with the pipe chosen, or propose a machine that is underpowered for the project. In addition, the industry is asking for more on-grade boring, and the software can help engineers develop those projects in a realistic manner.

Furthermore, some communities require a formal plan to be submitted before a project starts. In Canada, an HDD contractor must submit a formal bore plan on all pipeline projects. Environmental guidelines do not allow for frac-outs on pipeline projects. Contractors must submit a plan that includes estimated mud pressures below ground and must have a plan in place to monitor downhole pressure to avoid potential frac-out situations.

Word of caution

Dubbin stresses caution when using bore planning tools, as unforeseen obstacles can always sidetrack a well-planned bore. “You can’t see what is happening down in the ground during a bore, so you never know what may happen,” he says. “There are a lot of variables that a person can’t control, so it helps to be prepared.”

One factor that can be difficult to prepare for is changing ground conditions. Dubbin encourages drill operators to watch the returns on a pilot bore. The colors provide clues to the type of soil in which they’re working. If the returns are brown, then suddenly turn to dark brown, light white or gray, the drill is entering a different soil.

That soil type may require additional mud. For example, a contractor needs to pump three to four times as much mud into clay than into sandier soils, as it takes more force to remove the dirt particles from the hole. This is a condition bore planning tools cannot predict.

Drilling in rock is also unpredictable, because a 20,000 psi rock drills much differently than a 42,000 psi rock. However, core samples along the bore path can be extracted and factored into the plan. This helps determine, rod-by-rod, when the drill enters and exits unique rock formations.

Practical applications

Erv Hoge of Earth Energy in Boise, Idaho, understands the value of bore planning software. His HDD company specializes in utility installations of the kind most contractors would shy away from. “We deal with some pretty challenging bores, and our planning software is a huge asset,” Hoge says. “Several years ago, we created our bore plans using hand levels and tape measures and created the bore path by hand. It took considerable time. With lasers and our planning software, it’s much easier and more efficient to map the topography and design the bore.”

Earth Energy documents every bore, whether 30 or 1,000 feet, using a combination of planning software and bore logs. Often, the company has been hired to go back and complete a bore in the same area as a previous project. “The bore logs and planning files are a great help in determining where we put the previous bore, what utilities we encountered, where existing utilities are, and what depth we bored,” says Hoge. “The information is great to share with a customer, and it helps us better estimate the cost of the project.”

Earth Energy tracks the depth of every rod and sometimes every half-rod. The crew follows along the bore plan profile to track any variances. In the end, an as-built is created and compared with the design. “The software takes the guesswork out of the planning process,” says Hoge. “If we try to design a bore too short and too steep for a particular drill, the software will flag the problem and walk us through the steps to correct the situation.

“Bore planning software helps save our company time and money. More important, it helps us account for unforeseen challenges before they become a reality. That confidence is worth a lot to our company and our customers.”


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