HDD in the Bayou

Monty Scruggs with Isaacks Directional Drilling has some basic advice when it comes to large-diameter pipeline installation projects — don’t take a knife to a gunfight. Scruggs recently took his own advice on a river crossing project located near Vicksburg, Miss.  

Isaacks Directional Drilling was hired by Progressive Pipeline Co., based in Meridian, Miss., to install 4,500 ft of 24-in. pipeline designed to transport carbon dioxide to oil fields located in Louisiana. The bore was part of the larger 68-mile Delta Pipeline extension being constructed by Denbury Resources between Tinsley, Miss., and Delhi, La.

// ** Advertisement ** //

The carbon dioxide is used to help extract additional amounts of oil from reservoirs in mature, depleted oil fields and is often referred to as tertiary or enhanced oil recovery. Carbon dioxide acts like a solvent, removing the oil from formations in the rock, helping to recover previously unattainable oil from existing fields. Denbury Resources obtains the majority of its carbon dioxide from the Jackson Dome, located in central Mississippi, which was once associated with an old volcano. The company currently has more than 400 miles of carbon dioxide pipelines in place with plans to add hundreds more in the coming years.

Isaacks Directional Drilling was formed by Buddy and Jo Ann Isaacks as a small utility installation company back in 1990 in Aransas Pass, Texas. The Isaacks have watched the company grow over the years into a much respected underground installation contractor. Today, the company operates five directional drills and specializes in horizontal directional drilling (HDD) and boring, mainly for gas and oil pipeline projects throughout the southern states stretching from Texas to Florida.  

// ** Advertisement ** //

“Our success ties back to planning,” says Scruggs, operations manager for Isaacks Directional Drilling. “It’s important to size up the job and make sure you anticipate your needs. You need to match the drill rig to the anticipated pulling loads to eliminate surprises, and on the type of projects we work on, it’s imperative to have experienced operators. Our team has been around for quite some time.”

Navigating a Bayou

Progressive Pipeline was hired to oversee the 68-mile installation project. However, portions of the project had to navigate environmentally sensitive areas in Mississippi and Louisiana. These areas consisted mainly of bayous, bodies of water typically found in flat, low-lying areas. Bayous can be extremely slow-moving streams, marshy lakes or wetlands.

// ** Advertisement ** //

The Delta Pipeline extension was designed to pass directly through the Steele Bayou, a gravity control structure that is part of the Yazoo River backwater project, near Vicksburg, Miss. Basically, the Steele Bayou is a system of levees and channels designed to protect alluvial lands from flooding by backwater of the Mississippi River.

Isaacks Directional Drilling was hired to install the 24-in. diameter pipe directly under the bayou that stretched from Mississippi to the Louisiana side of the state line. The project required the bore to run underneath a 1,000-ft wide canal and then another 3,550 ft of wetlands to the drill exit.

// ** Advertisement ** //

Typically, with long bores, contractors will encounter many challenges — this project was no exception. The team had to address extreme topography changes, the environmentally sensitive bayou, difficult access to water and the extremely soft ground conditions.  However, Scruggs knew there was going to be one constant — sandy soil conditions throughout the bore.

Access to the site was attained by traveling down a board road stretching six miles. Progressive Pipeline built the board road to accommodate the heavy equipment Isaacks would bring to the site. However, despite the road it still took two full days to get their equipment to the site and ready to start the pilot bore.
“The road passed through wetlands and was challenging from the aspect of towing in our equipment. It took 30 minutes in a passenger truck just to reach the bore site from the highway,” says Scruggs. “Our equipment got stuck many times.”

// ** Advertisement ** //

The second challenge was access to water. Hauling water to the site wasn’t an option due to the time required to navigate the board road. Plus, Scruggs feared the truck would just get stuck in the wet ground conditions. So Scruggs and his crew decided to pump water from the canal to the drill rig. While the drill rig was set up only 1,800 ft from the edge of the winding canal, Scruggs had to pull water from another portion of the canal more than a mile away due to the entry site setup. A duplex pump moved water through a 3-in. poly pipeline back to the drill rig.

To help achieve the success on any large-diameter bore, it’s important to have adequate equipment on the site. Isaacks Directional Drilling owns five Vermeer horizontal directional drills, ranging in size from 80,000 to 750,000 lbs. For this project, Scruggs selected its Vermeer D750x900 Navigator horizontal directional drill.

// ** Advertisement ** //

More Than a Mile

The bore began using an 8.75-in. roller-cone bit combined with a jet assembly for the pilot bore, which took three days to complete. Scruggs knew the terrain and interference could cause problems with his existing locating system, so he decided to use a gyro tool to help guide the pilot bore.

“It would be extremely time consuming for traditional wire line guidance on this project due to the bayou terrain and lack of drainage in this area,” say Scruggs. “The gyro tool uses GPS to guide the bore. We enter in the longitude and latitude of the entry and exit points and the system guides the drill operator from the start to the ending point of the bore. It takes out a whole lot of legwork up and down the drill path.”

// ** Advertisement ** //

During the pilot bore, the crew hit a little bit of gravel and clay, but the majority of the bore was completed in sand as expected. The depth of the pilot bore reached 120 ft as it passed under the canal in order to maintain the required 30 ft of cover required by Denbury Resources. One of the main concerns was keeping the bore hole open in the sandy soil. To help overcome this challenge Scruggs worked with his drilling fluid supplier to develop a mud program that helped to keep the sand at bay and hold open the hole.

Once the pilot bore was completed, a 24-in. wagon-wheel cutter was pulled back through the pilot bore. This was a slow process and took four days to complete. A second pre-ream was completed in five days using a 36-in. wagon-wheel cutter. According to Scruggs, the mud mix did its job and held the bore hole open throughout the entire process. Following the final 36-in. pre-ream, the crew attached a 30-in. swab to the drill stem and cleaned the bore hole before attaching the 24-in. product pipe to the swab head for the pullback.

“We started pulling back the product pipe at 9 a.m. and finished with the final joint at 2 a.m. the next morning,” says Scruggs. “It took some time, but we monitored our pull loads closely and completed the project without a hitch.”

The entire project took 26 days to complete and was delayed due to the unusually wet weather and the fact that trucks and supplies had a difficult time reaching the project site.

Greg Ehm is a features writer with Two Rivers Marketing, Des Moines, Iowa.

Bookmark and Share

// ** Advertisement ** //