水平定向钻探（HDD）项目多年来一直在规模和范围上有所突破。每个项目的直径都比下一个更长，直径更大。在北达科他州巴肯地区的一个项目的另一个结果是，为以前未开发的大部分能源创建了一个可持续的新交付网点。
这种令人难以置信的HDD交叉使用相交方法穿过密苏里河上的Sakakawea湖，连接2.5英里路线的两端（总长13247英尺），使用直径20英寸的管柱和两个定制钻机进行连接具有超过100万磅的推拉力。
该项目给承包商带来了许多挑战，包括延迟的启动，陡峭的进出角和偏远的工作地点。使用HDD作为安装方法还消除了使用成本更高的替代方案的麻烦，该替代方案不得不分流数百个湖周围数英里远，从而为项目所有者金德·摩根（Kinder Morgan）节省了大量资金。
2020 Project of the Year New Installation: Bakken Missouri River Crossing
Horizontal directional drilling (HDD) projects have been pushing the envelope for size and scope for many years. Each project getting longer and larger in diameter than then next. A project in the Bakken area of North Dakota had an added result of creating a sustainable new delivery outlet for a largely previously untapped energy source.
This incredible HDD crossing utilized the intersect method to cross Lake Sakakawea on the Missouri River to connect two ends of a 2.5-mile alignment — a 13,247-ft total crossing — using a 20-in. diameter pipe string and two custom-made drill rigs each with more than 1-million lbs of push/pull capacity.
This project provided a multitude of challenges for the contractor including a delayed start, steep entry and exit angles and a remote location to work in. Using HDD as the method of installation also eliminated the need to use a more costly alternative of having to divert hundreds of miles around the lake, thus saving project owner Kinder Morgan a substantial amount of money.
For all of these challenges and accomplishments, the Bakken Missouri River Crossing was selected the 2020 Trenchless Technology Project of the Year for New Installation.
“Michels [Corp.] is routinely pushing the boundaries in developing new tools and ideas. We’re honored to have been selected the [Trenchless Technology] Project of the Year,” says Matt Smith, general manager of Michels’ HDD operations. “We can really use this as a benchmark to continue to push the industry forward, taking the techniques that are developed today and making them better for tomorrow.”
“[This project] opens the door to these longer crossings,” says Jeff Mueller, vice president of Michels HDD operations, as well as a 30-year veteran of the HDD industry. “We’ve crossed this particular body of water four or five times and all of those crossings have been over 10,000 ft. Our experience in that area as well as our ability to do these long crossings opens the door for a lot of gas and oil clients to look at doing longer drills in the future. [This project] is outstanding because it’s a milestone of a larger diameter that sets the stage for future work, in my mind.”
Crews prepared to drill through compacted clay, sand, rock and coal seams. Guided by gyroscopic tracking and downhole tools, the two pilot holes met almost exactly in the middle.
The project successfully culminated in October 2019 with a two-day pullback of the massive snake trail of pipeline welded in three strings by Michels pipeline construction crews, traversing the hills and valleys of the terrain adjacent to the lake.
A rig with 1.8-million lb push/pull capacity was positioned on the south side of the lake (entry side) and a rig with 1.2-million lb push/pull capacity on the north side. The 20-in. pipe string laydown area was 75 ft wide by 6,000 ft long, looking like a snake trail due to the vast undulating landscape.
Elevation changes were 10 to 30 ft. The pullback started with an 1,100-ft section was followed by two sections of about one mile each; after each section, the pullback was stopped to perform the tie-in welds, X-ray and coating operation, adding to the additional risk associated with pulling back this diameter and length of pipe.
Project Background
Michels was contracted by Kinder Morgan for HDD and pipeline support to complete the 13,247-ft Bakken Missouri River Crossing (BMRC) under Lake Sakakawea on the Missouri River. In addition to its noteworthy length of 2.5 miles, this project provides a previously unavailable trenchless option for transporting natural gas without disturbing the lake bottom.
Prior to this project, the two-mile wide Lake Sakakawea and lack of infrastructure separated about 30 percent of Bakken natural gas from processing plants, requiring it to be flared instead of used, according Kinder Morgan. Gas flaring has become a major environmental concern facing the world today, as it generates a significant amount of greenhouse gas, which contributes to the overall burden of climate change. This energy source can now be reliably transported to market, as the two shores of the pipeline were bridged via the intersect method.
This project presented a number of challenges and obstacles along the way, including the overall length and diameter of pipe to be drilled in such a remote location — conditions not dealt with in their experience. “For this size pipe, there wasn’t anything or any experience we could glean on from our past projects,” says Smith, noting that Michels relied on the industry experience of its crew to complete the crossing.
Location of the crossing was extremely remote, far away from paved roads or any highways or towns, making getting supplies to the site difficult. Michels constructed access roads and other improvements to secure truck traffic in and out during all weather conditions.
“We do work in remote locations all over the world and the United States,” Mueller says. “Our experience is that we know what to bring to these kinds of projects. You come prepared. You come with plenty of spare components and parts that you would typically see in a crossing of this length. Plenty of spare tooling and keep a spare steering tool onsite. On these types of projects, you don’t want to be waiting for a spare tool to show up.”
The crossing was performed in late August/early September 2019 to meet an environmental permit requirement banning activity taking place during the Dakota butterfly flight season. This pushed the schedule up against a tight window for completing it prior to the bitter cold winter months, which could wreak havoc on water-based drilling operations and pipeline testing procedures prior to pullback. Final pullback was completed in October 2019, during a minor snowstorm with frigid temperatures.
This crossing started several years prior to completion with an extensive planning and permitting process, Kinder Morgan held several meetings with the U.S. Army Corps of Engineers regarding HDD procedures specific to protecting the pristine lake from environmental impacts. Ultimately, HDD was selected as the preferred construction method because the pipeline would be built well below the lake bottom and would present far fewer surface and environmental impacts vs open-cut installation.
Mueller notes that one of the concerns the Army Corps of Engineers had was the potential for fluid loss into the water body. “It was concerning to them that this [project] was being done in an area of North Dakota that some coal in the [soil] formation,” he explains. “Coal tends to lead to circulation loss and they had some concerns with that particular formation. By utilizing the intersect method, it helped to reduce those annular pressures.”
The Michels team used its engineered fluid program to mitigate any potential fluid losses into the formation.
Although the lake is only 30 to 35 ft deep, the banks at this crossing location rise as a cliff to 280 ft on the north side of the lake and 60 ft on the south side, giving it an expansive setting. The approved drill path required the crossing to be completed 265 ft below the bottom mudline of the lake based on a hydraulic fracture analysis. Turbidity curtains were pre-staged and deployed to protect the lake should an unexpected inadvertent release of drilling fluid occur.
Michels’ specialized tooling and expertise in mud management planning allowed drilling fluid pressures to be maintained, resulting in the project being completed without any unplanned release of fluid.
Mueller marvels at how far the HDD industry has traveled since his introduction to it in 1989, when he started out doing 500-ft crossings with zero surface guidance. “We preform many significant projects every year,” he says. “We always want to push that envelope. That is the direction this market is going. There are large obstacles in the world that need to get crossed. If you can get an engineer to design these projects and can get a contractor that is willing to take the risk to perform it, it opens the world to a lot of future projects that two or three years ago would have been unachievable.”
Regulatory entities (including the U.S. Army Corps of Engineers) are placing more emphasis on proper HDD design including documentation to demonstrate that inadvertent return risks can be managed to avoid unwanted environmental issues associated with the loss of drilling fluids from an HDD bore during drilling operations.
Kinder Morgan retained the services of Mott MacDonald to perform a detailed design of the proposed HDD installation and provide recommendations for enhancing the success of the crossing. As part of this design work, Mott MacDonald performed a series of hydrofracture evaluations based on the anticipated geotechnical materials, site topography, and pilot bore drilling parameters. These evaluations helped to identify the required installation depth necessary to meet the requirements set forth by the USACE and establish the required drill and intersect zone for the installation. Mott MacDonald summarized their hydrofracture evaluations in a detailed white paper, which was instrumental in securing the USACE permit for this crossing.
Kinder Morgan also utilized Mott MacDonald’s services to perform reviews of HDD construction work plans and construction inspection services during the HDD installation. While the subsurface conditions closely aligned with geotechnical reports, on-site inspectors provided real-time feedback and observations to Kinder Morgan and Michels throughout the drilling process.
