Rigonomics Supplement: Tips From A Rock Drilling Specialist

By Jeff Griffin, Senior Editor | June 2011 Vol. 66 No. 6

H&H Enterprises is a HDD contractor specializing in rock with 15 years of experience working primarily in the Northeastern United States.

H&H operates three American Augers HDD units ranging in size from 60,000 to 440,000 pounds of pullback and all required support equipment, including mud pumps, mud recycling systems, vacuum truck, crane trucks, pipe layers, excavators with pipe-handling equipment and haul trucks.

A recent project employed two drills: a 60,000-pound drill unit and a 220,000-pound model to drill 1,200 foot holes. One was for a 16-inch HDPE water line and the other a 12-inch steel gas line. Rock hardness was 25,000 psi. A 4 3/4-inch Adtech mud motor was used with 6-inch sealed bearing tri-cone bit and multiple Sharewell low torque hole openers in sizes ranging from 14 to 30 inches.

The first step in a successful HDD project is understanding its specifications in order to prepare a realistic bid, especially when rock is a factor.

“Standard industry bidding practices and procedures apply to all projects, but rock drilling takes significantly more time to correctly bid compared to projects in dirt,” observes Jason Hockran, H&H vice president/owner. “On rock projects, it is crucial to recycle drilling fluids and to include the costs of fluid recovery and disposal. This applies to most HDD projects, but usually is more costly on rock projects.”

Hockran emphasized that every successful HDD project should begin with planning, especially those in rock.

“The busy rush of almost every directional drilling project may cause contractors to overlook basic planning steps,” said Hockran. “Taking the time to think through the steps for the HDD process, utilizing the capabilities of your equipment and knowledge of your crews, and focusing on safety all lead to an effective project plan.”

Client communications
Because many customers are not familiar with HDD in general and less with HDD in rock, Hockran said communicating with the customer regarding the specifics and limitations of HDD rock drilling is important.

“Typically rock projects require longer drill lengths than dirt, so communicating about scheduling and drill path limitations are a key to establishing and meeting expectations for directional drilling in rock,” he said.

Matching equipment to project needs is important. Whether or not a job calls for a mud motor is an important decision for the contractor.