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Michels USA completes 10 HDDs in Gulfstream pipeline expansion.

In July, Gulfstream Natural Gas System L.L.C. began a 110-mile mainline expansion of its two-year-old transmission pipeline. Placed into service in May 2002, Gulfstream is a state-of-the-art natural gas delivery system. As Florida's first new natural gas pipeline in more than 40 years, the system has the capacity to transport approximately 1.1 Bcf/d of natural gas to a wide array of customers, including electric utilities, local distribution companies and municipal users.

"We've come a long way in a very short amount of time and are looking forward to continuing to expand our system to meet the needs of the market," says Brad Reese, Gulfstream vice president and general manager. "Florida's natural gas markets are growing and we are committed to doing the right things to grow along with them."

Jointly owned by Williams and Duke Energy, the 581-mile Gulfstream pipeline system is the largest natural gas pipeline in the Gulf of Mexico. The system originates near Pascagoula, MS, and Mobile, AL, crossing the Gulf with more than 430 miles of 36-inch diameter steel pipe to Manatee County, FL. Once onshore, 130 miles of pipe, ranging in diameter from 16-36 inches, cross Manatee, Hardee, Polk and Osceola counties.

Mainline Expansion

When Gulfstream decided to lengthen the pipeline's reach from central Florida to the state's east coast and double its service area, the company awarded the contract for the 110-mile mainline extension to Sheehan Pipe Line Construction Company, Tulsa, OK.

Working on the Gulfstream is not new to Sheehan crews since the company installed most of the initial onshore segment of the original line in 2001-02.

Scheduled for completion in December, the mainline extension calls for construction in five Florida counties: Polk, Hardee, Highlands, Okeechobee and Martin; it also required horizontal directional drills (HDDs). As the main contractor for the Phase II expansion, Sheehan subcontracted the HDD work to Michels USA Inc., Brownsville, WI.

Michels' Design Engineer Gregory Goral said crews completed 25,000 linear feet of 30-inch directional drill installations in south central Florida to accommodate crossings at three locations near Highway 98, including the North and South Hwy 98 Flood Plains, beneath both the Peace and Kissimmee Rivers, two creeks, two canals and Chandler Slough.

Goral said the 10 completed crossings had lengths ranging from 1,450 to 4,096 feet. The crossings were all drilled with up to 70 feet of cover. He said the longest bore--4,096 feet--was under Chandler Slough, one of an interconnecting network of sloughs, man-made canals and natural creeks that drain to the Kissimmee River and Lake Okeechobee.

"Michels did a terrific job for us," said Chris Springer, Gulfstream phase II project manager. "They did a great job managing a tight construction schedule."


In preparation for construction, Gulfstream conducted extensive site and environmental Investigations to determine the potential for the occurrence of special status species or their habitats in the project area.

Gulfstream developed a schedule that minimized disturbance to the affected species, which included the likes of heron, squirrels, burrowing owls and bald eagles. An extensive soil investigation was conducted and transcribed onto preliminary profile drawings to provide an accurate account of soils crews were likely to traverse during planned drilling operations.

Goral said, "Before the work began, a preliminary site walk-through was conducted to give all the contractors a clear picture as to the expected conditions of proposed work sites. Sheehan's crews also made sure that drill sites and access to them were prepared before mobilization of the HDD equipment."

All 10 crossings required the installation of 30-inch diameter steel pipe coated with 14-16 Mils FBE coating and 40 mils abrasive resistant overlay.

Entry points for some of the crossings were established in low lying areas requiring access matting from main roads. Exit locations were similar to entry locations, requiring matting from main access roads.

"All the HDD crossings were pre-designed reflective of industry standards with minimal risk posed in completing the crossing from a geometric perspective," Goral explained. "The size and length of the proposed crossings subsequently attributed substantial risk for successful completion. During the usual tailgate safety meetings, an inadvertent drilling fluid release plan was established prior to the work commencing."

Other pre-construction activities included the required environmental and safety training of all contractor personnel. Containment berms required around various equipment locations were established and special provisions were made for water supplies.

Equipment Spread

Michels mobilized three drill rigs to the job sites and supporting crews to complete the installations. The equipment spread included two 1.2 million-pound capacity drill rigs and one 840,000-pound capacity rig with ancillary equipment.

Drilling of the crossings started in June and installation was complete by the first week of July, just weeks before Sheehan crews began the mainline construction. Goral noted that weather conditions at the HDD locations were sometimes problematic. Frequent afternoon thunderstorms often temporarily halted drilling operations.


Goral said, "One thing that stood out as unusual was that five of the 10 crossings were within one square mile of each other, allowing a single drill site to be used a second time for the next crossing."

This proved to be beneficial in several ways since it allowed crews to use the same water source and mud disposal location for multiple crossings.

As the HDD crew set up to complete the respective drills, Sheehan crews were busy welding the pipe to be pulled back into the bore hole. As the work progressed they also assisted with final pullback operations.

Once drilling was under way, the pilot holes for the respective drills were punched into the ground at pre-established entry points provided and staked by Gulfstream.

"Drilling of several of the crossings proved so precise that they actually knocked over the pre-established exit stake," Goral explained.

Difficult Drill

Of the 10 HDDs completed, Goral said the 3,720 linear-foot crossing of Kissimmee River proved to be one of the more difficult. This was due in part to environmental constraints which required constant monitoring of the drill path alignment because the Kissimmee is categorized as one of Florida's pristine rivers. Michels also encountered difficulty drilling through changing formations which included swelling clay and zones having high concentrations of groundwater filtration.

Other Obstacles

In describing other obstacles Goral said that when stringing out tracking coils, personnel had to contend with swamp inhabitants such as alligators.

And as work progressed, soil conditions posed problems when downhole drill fluid returns were not sustainable. Goral said drill stem would be extracted several joints in order to size the borehole and re-sustain annular circulation.

To accommodate hole clean-out operations, crews relied on 42-44-inch diameter reamers. This, too, was not always easy. The advancement of reamers posed challenges due to varied soil conditions encountered and fluid circulation constraints. Once reaming operations were completed, the 30-inch diameter pipe was pulled through the bore hole.

The proximity of the drill locations to the various water bodies also impacted construction activities. Any frac out or release of sediments into the water would have resulted in immediate shutdown of the work, plus other penalties, not to mention the impact on the mainline construction that was to follow.

Time constraints also posed a challenge. All 10 crossings had to be competed within a three-month window, starting June 1. To meet this schedule, Michels had to allocate three large-capacity drilling rigs with crews before Sheehan began the mainline construction in July.

Project's Success

Goral attributes the success of the project to the working relationship between Michels, Sheehan and representatives of Gulfstream.

"The preliminary planning and coordination that went into the design and scheduling of materials, personnel and equipment was reflected in the overall success of this project. Daily operations personnel--both on-site and from the home office--contributed substantially in addressing unexpected issues as they arose. Through this teamwork and support, the 10 crossings were completed with minimal difficulty," he said.
Gulfstream Natural Gas System
Phase II: Horizontal Directional Drills


Peace River South Hardee 2,050
Seepage Wetland Polk 1,700
Arbuckle Creek Highlands 2,045
Istokpoga Canal Highlands 1,450
Kissimmee River Highlands/Okeechobee 3,600
Highway 98--North Flood Plain Okeechobee 2,125
Highway 98 Okeechobee 2,700
Highway 98--South Flood Plain Okeechobee 1,900
Chandler Slough Okeechobee 4,096
L-65 Canal Martin 3,125
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Title Annotation:Directional Drills
Author:Tubb, Rita
Publication:Pipeline & Gas Journal
Article Type:Brief Article
Geographic Code:1USA
Date:Nov 1, 2004
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