The Zulia state in southwestern Venezuela is the primary oil-producing region of this South American nation, with many companies engaged in petroleum operations there.

When natural gas and oil pipelines needed to be constructed between the Catatumbo oil field to the Redoma pump distribution station 36 km away, the project was complicated by the Tarra River, which provided a formidable barrier.

The terrain and environmental considerations ruled out crossing the river by open-cut construction.

Horizontal directional drilling was determined to be the only way to make the river crossings, and the general contractor of the project brought in HDD specialist Servicios Flowtex de Venezuela, S.A. to install pipe under the river with its horizontal directional drilling equipment.

The company’s crew made two river crossings, each to install 152 mm steel pipe. One was for the natural gas pipeline and the other pipe transports petroleum. Installations were parallel to one another, 20 meters apart. A 60-meter HDD road crossing also was made as part of the project.

At the point of the crossings, the river is 150 meters wide and 3.5 meters deep, says Jose Ignacio Briceno, Flowtex project manager.

To insure the project went smoothly, the bores were planned with the Subsite^® Trac Management System (TMS).

All bores were made with a Ditch Witch JT2020 directional drilling unit that develops 17,000 pounds (76 kN) of thrust and 20,000 pounds (89 kN) of pullback, 1300 foot-pounds (1763 N·m) of torque, and has a maximum spindle speed of 150 rpm.

“Soil conditions under the river were mostly sand and gravel with reactive clay formations near the surface at banks on both sides of the river,” says Briceno. “Loose formations made guiding the drill head difficult.”

With careful planning, patience, and skill, the two crossings were successfully completed.

Preplanning with Subsite TMS helps avoid problems while making installations. TMS computer-based technology plans the optimum path for the pilot bore, documents variables during drilling, and can prepare as-drilled maps of completed projects. During drilling, real-time information about the job’s progress can be compared to the planned bore path. TMS operates in conjunction with the drilling unit’s Subsite electronic guidance system.

To permit proper approach and exit angles, the planning system called for one bore to be 242 meters long and the other 235 meters. Maximum depths were 8 meters.

The pilot holes were completed in only two days. A Subsite 750 Tracker was used to monitor the location of the drill head, with personnel wading through the water while the head was under the river. A sand bit was used for the river crossings and a Durabit for the road bore. Baroid de Venezuela provided drilling fluids.

“After each pilot hole was completed, we enlarged the hole with 8- , 10-, and 12-inch Beavertail backreamers,” says Briceno. “Then the 10-inch backreamer was connected to the drill string again, the steel pipe attached, and the pipe was pulled through the pilot hole. The installations were completely successful.”

The project is a joint venture of Argentine company Tecpetrol and Petroleos de Venezuela. General contractor was SADE Skanska, an international company based in Sweden.

Briceno and Marco Faenza, manager director of Servicios Flowtex de Venezuela, S.A., planned and coordinated the project with Briceno in charge of field operations. Technicians were Jose Manual Silva and Jose Caraballo with the assistance of Carlos Lovato of Flowtex Argentina.

Servicios Flowtex de Venezuela is a HDD contractor making installations for oil, gas, and water pipelines and fiber-optic cable.

“Directional drilling is the only trenchless procedure we use,” says Faenza.

The company owns four HDD units. In addition to the JT2020, they include two other Ditch Witch models, a JT1720 and new JT4020 Mach 1. The compact JT1720 develops 67 kN of pullback force, 2440 N•meters of spindle torque, and spindle speeds to 200 rpm. The larger JT4020 Mach 1 produces 178 kN of pullback, 6780 N•meters of spindle torque, and maximum spindle speed of 250 rpm. Servicios Flowtex de Venezuela began HDD operations four years ago, and has seen the need for directional drilling services grow rapidly.

“I would say demand has increased 65 percent or more in the past year,” says Faenza. “There are several reasons for this: Because our country has many mountains and rivers, HDD sometimes is the only way pipelines can be installed. And oil and gas regulators like very much this technology because it preserves the environment. In addition, the large number of successful installations make directional drilling appeal to project owners.”

Faenza believes the HDD industry will continue to expand in Venezuela and other Latin American countries.

“I am sure of it,” concludes Faenza. “And we plan to expand our operations to other countries, such as Colombia and Ecuador.”