HDD and Flood Relief Aid
January 19, 2012The incredibly wet summer of 2011 will long be remembered for its devastating floods throughout the Midwest.
While the fallout from the flooding had widespread consequences, the impact on existing utilities was widespread and hard-felt. Particularly ravaged were utility lines near Decatur, Neb., where the flooded Missouri River claimed three parallel pipelines owned by two Midwestern utilities.
The concern over a potential rupture in one line and imminent jeopardy of the other lines following suit, the utilities acted quickly to call on an experienced horizontal directional drilling (HDD) contractor capable of providing the total scope of work in an emergency situation.
They called on Michels Directional Crossings.
The Scene Is Set
As North America’s longest waterway, the Missouri River trickles out of the mountains in Montana, flowing southeast through seven states before dumping its contents into the Mississippi River. The Missouri’s 2011 flooding began in late-spring and continued through the summer months as floodwaters spilled over the river’s banks and rushed into fields and towns, with some flooding taking place up to five miles from the river’s normal edge. All told, the flooding directly impacted seven states, including Montana, North Dakota, South Dakota, Nebraska, Iowa, Kansas and Missouri.
It was nowhere more apparent than on the Nebraska-Iowa border near Decatur, where the dramatic influx of rushing water created scour points at various river crossing locations.
The three pipelines were each 8 in. in diameter and all carried a different substance — ammonia, liquefied petroleum gas and natural gas liquids.
Once the first line was suspected of rupturing, all of the lines were immediately taken out of commission. The utilities sprang into action to find a constructible solution for getting the three lines back in service as soon as possible. Because of the unique situation in working for two separate pipeline companies on the same project, it was crucial that all personnel be operator-qualified to perform the work for both companies.
The main issue was that floodwaters were still rising, which made conventional construction virtually impossible since the Missouri River had extended its reach to farm fields normally adjacent to the river.
It quickly became clear that construction by HDD was the most viable option for reducing the amount of pipeline downtime.
Just as quickly, it became clear that one HDD company — Michels Directional Crossings — was more suited than the rest to handle the entire scope of work, which included:
- Preparing two large drill pads on both sides of the river for three separate side-by-side HDD crossings
- Preparing 7,200 lf of pipe laydown area on the Iowa side of the river to accommodate the three separate pipe string-outs
- Removing a portion of the three existing lines
- Welding 21,100 lf of 8-in. steel pipe
- Completing three 8-in. HDD crossings of roughly 7,000 ft
- Associated testing and tie-in work
Additionally, the entire scope of work had to be completed as safely and proficiently as possible in order to minimize disruption to the product lines.
Preparation and Initial Drilling
The vast construction resources available to Michels Directional Crossings as part of Michels Corp. helped immensely on this project, as Michels Directional Crossings was able to quickly mobilize to the site and coordinate with Michels Pipeline Construction to obtain additional equipment and personnel.
Due to the extremely time-sensitive nature of the project, Michels mobilized to the site within a week, and work immediately began on preparing the Iowa side for mobilization of the drill rig and delivery of the 8-in. steel pipe for the following week.
To accommodate the drill rig pad and drilling operations, the three existing pipes had to be exposed and removed on the Iowa side.
With the pipes out of the way, the drill rig was quickly ready to work and began drilling a pilot hole in the sandy, gravely conditions on Sept. 19. Meanwhile, a second drill rig site was being prepared on the Nebraska side and was ready to start drilling just days later, which was crucial in the timely completion of Michels’ state-of-the-art pilot hole intersect drill.
Highly compacted gravel conditions posed a minor speed bump to the Michels team, but Joe Lechner and Cale Mullenix, two experienced drill rig operators, worked through the difficult conditions and soon found more favorable ground.
Due to expected magnetic interference from the existing lines and the proximity of these lines to the new crossings — combined with the limited access to the flooded lowlands for laying secondary tracking cables along the ground surface — Michels chose to deploy a combination of proprietary tracking systems to track the lengthy pilot holes while drilling toward each other from both sides of the river.
While the logistical challenges of a drill like this are never anything to be overlooked, the difficulties were compounded on this project due to the closure of the Decatur 175 toll bridge between Decatur, Neb., and Onawa, Iowa. Potential unstable conditions around support columns of the bridge forced its closure and resulted in limiting access to the other side of the river — the closest bridge now required an additional 100-mile drive. As a result of these logistical challenges, several limitations on the work locations which otherwise would benefit from the ability to readily sharing equipment and supplies had to be managed on a daily basis.
Still, even with all of these challenges, Michels successfully completed the first drill while cutting the expected drilling time in half due to the successful performance of a pilot hole intersect.
The Plot Thickens
With the first hole successfully drilled, the first line that was pulled was the liquefied petroleum line. Due to the customers’ needs, this line was immediately put back into service, which made the stakes a bit higher than normal on the two subsequent drills.
The proximity of the lines — just 15 ft apart — in such a narrow corridor was a challenging concern requiring the utmost oversight, but Michels confidently answered the challenge by carefully monitoring and mitigating any dangers by using innovative new tracking systems.
Additionally, because the line was back in service, the timeframe of the drills became even more compacted — it was necessary to suspend drilling from time to time due to line testing and the simultaneous overlapping of pipeline and drilling operations within the narrow work areas.
It became a race for time as improvements were made on successive drills in order to shave valuable time off the total project duration. Exceptional organizational efforts from Jim McGovern and Billy Rogers, the respective project managers from Michels Directional Crossings and Michels Pipeline Construction, along with the diligent execution of the work by their respective crews, made completing the drills and pullbacks a month ahead of the projected schedule possible.
Bob Wothe is a corporate writer and marketing specialist at Michels Corp., Brownsville, Wis.
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