Marcellus Shale Play HDD Challenges and Triumphs
December 27, 2011Gabe’s Construction has been in continuous operation since 1942 and over the years has ridden the ups and downs of the natural gas pipeline construction booms. The company’s first growth spurt was in the late 1940s installing natural gas distribution lines in Wisconsin for gas coming from Texas. The company is now experiencing another major natural gas growth cycle along with other pipeline and horizontal directional drilling (HDD) contractors to satisfy demand for the Marcellus Shale gas gathering, distribution and transmission.
Gabe’s HDD toolbox has remained flexible to meet customers’ demands — be it a 4,000-lf HDD gathering line or three 300-lf parallel gathering lines crossing a state highway. The increased demand for HDD crossings in the Marcellus Shale play has been accompanied by challenging demands on man and machine.
The increased speed of the shale play has intensified the challenges involved with HDD construction in the Marcellus region. The time necessary to properly plan and engineer crossings is not available as the pipeline operators and financiers require the system to be operational as quickly as possible in order to get gas to a demanding market and realize returns on their substantial investments. This increased speed of implementation can lead to issues of HDD crossings being designed without proper fundamentals of engineering.
The dramatic elevation changes due to the nature of the geography common in the Marcellus region (primarily, New York, Pennsylvania, Ohio and Virginia) make HDD operations more difficult, increasing the need for proper engineering of bore path plans and profiles with supporting soils and rock information. HDD profile radii are being pushed to the extreme to chase these large elevation changes that occur in shorter horizontal distances between entry and exit pits. These increased profile radii commonly come with high probability of dry bore holes, damage to pipe coating and of increased pullback forces, all of which may propagate into further concerns with completed HDD projects on time and within budget.
Proper field engineering, execution and planning of the HDD process are needed to overcome these difficult geographic obstacles and decreased project durations. Gabe’s continues to work with pipeline owners, engineers and contractors in order to provide real-world HDD knowledge that can be introduced at the design stage, setting an early precedent for a successful project.
Planning, Not Reacting
As with any successful company; Gabe’s has always held the mindset that it is better to plan than to react. This is of the utmost importance when dealing with the potential for inadvertent returns. The goal is always to limit the amount of inadvertent returns to zero on each project we undertake.
Allowing zero inadvertent returns cannot be guaranteed and is not always possible due to the typical formations of highly fractured and layered rock and the limited depth of cover that is usually indicated in some initial designs. This limited depth of cover is the result of working in deep valleys in difficult terrain and major elevation changes.
So Gabe’s Plans.
Gabe’s sets in place multiple environmental and safety plans on each project that are reviewed in detail with crew members before drilling is started. These plans include detailed inadvertent return bore-line monitoring procedures, required notifications and response, cleanup and disposal plans. Creating, implementing and using these plans are made even more challenging by the limited access to non-entry/exit sites as large equipment and vacuum trucks cannot be driven to the location of the majority of sites. Small pumps and UTVs are used to minimize the disturbance to access roads and landowners property.
Having a detailed plan in place that the full crew is knowledgeable about and having the anticipated equipment and manpower onsite and available to provide quick response times can assist to alleviate the issues of inadvertent returns. This contributes to successful completions of HDD crossings in timeframes, which satisfy pipeline owners and contractors.
Tight right-of-way confines not typical to maxi-rig directional drilling make for creative alternatives to setting up HDD equipment. This creativity includes benching out hillsides to place HDD rigs and placing mud systems on the crests of hills with piping down to the drill rigs. This is not the normal matted drill sites that HDD contractors are accustomed to. HDD contractors also may have to move HDD rigs for pullback since there is no room to lay out pipe on the exit side. Making multiple mid-welds to complete pullbacks can require two to three shifts of crews to complete crossings. Again, the distinct geographic terrain in the shale play is what creates these challenges. Owners, contractors, engineers and field staff need to efficiently plan, implement and communicate operations to coincide with work of all companies while in the confines of tight right-of-ways. This necessary daily communication between parties can be challenging as cellphone communication is spotty in northern areas, making instant communication a challenge. To overcome this delay, crews are reverting back to other means of communication such as truck CB radios and satellite phones.
As Marcellus shale pipeline systems continue to be installed at a rapid pace, there is an increased need for local, qualified and competent disposal sites for waste drilling fluids and spoils produced during routine HDD work. Many times disposal sites are confusing the liquids and spoils from the down hole drilling companies vs. the liquids and spoils from horizontal directional drilling. HDD operations in this area typically use solely high-yield, bentonite clay-based mud and do not typically include any mud additives that require special attention to handling and disposal. As growth continues in this and other markets, mud separating technology will likely become crucial in working toward the elimination of liquid spoils and easing the burden on disposal sites. Gabe’s continues to put forth substantial efforts to be on the leading edge of improvements in environmental sustainability, technology and productivity.
These are just a few of the many challenges that exist in providing quality and successful HDD crossings in the Marcellus shale region. The choice of qualified contractors is integral to minimizing the risk associated with HDD crossing in these atypical drilling conditions. Pipeline contractors and owners should continue to be aware of these challenges and choose qualified HDD contractors based on extensive past experience and reputation. Successful HDD crossings provide a stepping stone for an environmentally responsible pipeline project which shows the determination of the industry to protect and restore the habitat in which these projects take place.
Nicholas Atkin is vice president and Nathan Eastway, P.E., is chief estimator for Gabe’s Construction Co. Inc.
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