The Barnett Shale is more than 7,000 feet below the surface and is comprised of dense non-permeable rock. According to Dr. Ken Morgan, a geologist at Texas Christian University, “Solid hard rocks that are 7000 feet down don’t subside. You have more than a mile of solid rock that holds it all up. Subsidence occurs when you have loose, soft materials like in Houston (sands, clays, etc.) but not in cemented hard rocks like the Barnett Shale.”
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Pipeline development is important for the future of the Barnett Shale and the U.S. energy supply.
Explores the safest method of transporting natural gas, keeping it safe,
On June 7, 2010, in Cleburne, TX, in a tragic accident, an electric transmission company worker punctured a natural gas pipeline leading to the death of the worker and injuring at least eight others.
Pipeline development is important for the future of the Barnett Shale and the U.S. energy supply.
Facts About Pipelines
To move natural gas from the Barnett Shale region efficiently and effectively requires an elaborate transportation system. This system consists of a network of underground pipelines that safely move natural gas from its origin to processing and storage facilities and ultimately to customers for cooking, home heating and industrial use.
These pipelines add to an existing network of underground pipelines that transport water, sewage and other petroleum products. Read More...
Components of the natural gas transportation process
1. Treating and Processing Plants
2. Gathering & Transmission Pipelines
3. Compressor Stations
4. Metering Stations
Treating and Processing Plants
Gas at the wellhead is not the pipeline quality gas that consumers will use. Gas in the Barnett Shale normally contains natural gas liquids (NGLs), carbon dioxide (CO2) and water.
Processing plants separate NGLs into liquid products including ethane, propane, butane, isobutene and natural gasoline. Field processing plants are close to the production source. And straddle plants, which reprocess NGLs from gas pipelines, are located near the gas pipelines themselves.
As new pipelines are built in the Barnett Shale, new treating and processing plants will be added as needed.
Gathering & Transmission Pipelines
Pipelines fall into one of three categories: gathering lines, transmission lines and distribution lines.
Pressurized to varying degrees, natural gas is propelled through steel pipes. Gathering pipelines take natural gas from the wellhead to processing plants. Then transmission pipelines move the natural gas to marketing and distributing terminals. Natural gas is finally transported from a storage location to end-users via distribution lines. Interstate pipelines carry natural gas across state boundaries and in some cases across the country. Intrastate pipelines transport natural gas within a particular state.
Because the Barnett Shale region is one of the most prolific and well-producing natural gas regions in the U.S. and the demand for natural gas is increasing, it is imperative to expand our current transportation infrastructure.
Pipeline Construction
How are pipeline routes selected?
The first step in a new pipeline project is the feasibility analysis. Through the feasibility analysis, possible routes are identified and evaluated. The final route is selected based on the parameters of the project. Pipeline companies identify potential environmental concerns and impact to property when evaluating routes. To minimize impacts to property and landowners, pipelines are often built on existing electric or pipeline right-of-ways and along public land such as highways when permitted.
Several permitting and regulatory processes must be completed. Once the required permits are obtained and regulatory requirements satisfied, extensive land surveying begins. After surveys are conducted, the pipeline company works directly with individual landowners to negotiate legal easement agreements granting the company long-term rights to build and operate the pipeline and outlining how the landowner will be compensated for use of the land.
If the pipeline company and the individual landowner can not agree on the terms of an easement agreement, the pipeline company has the legal right – for the “public good” -- to request that the land be condemned and used to construct the pipeline project. By law, as outlined in the Texas Landowner Bill of Rights, landowners have the right to question a condemnation decision.
What is a right-of-way?
A right-of-way is the land above, and typically 25 feet on either side, of the pipeline.
This area, free of structures and landscaping, protects the pipeline from possible damage and allows pipeline operators to conduct preventative maintenance and foot and aerial patrols.
What is the construction process?
There are several steps in the pipeline construction process.
1. Clearing the Path and Stringing the Pipe
2. Cutting Trenches
3. Assembling Pipe
4. Lowering the Pipeline
5. Hydrostatic Testing
6. Land Restoration
7. Directional Drilling or Boring
1. Clearing the Path and Stringing the Pipe
The path of the pipeline is cleared of all removable impediments including trees, boulders, brush or anything else that may prohibit construction. Once the path is cleared for construction equipment to gain access, sections of the pipe are laid out along the path, a process called stringing the pipe.
The pipe sections are typically 40 to 80 feet long. Certain areas have different requirements for coating materials and pipe thickness.
2. Cutting Trenches
After the pipe is in place, trenches are dug alongside. Trenches are typically five to six feet deep, and in certain areas such as road crossings and bodies of water, the pipe is buried even deeper.
3. Assembling the Pipe
Next, the pipe is assembled and contoured. Sections of pipe are welded together into one contiguous pipeline. It is bent slightly, if needed, to fit the contour of the pipeline path.
Special coating is applied to the ends of the pipes (the coating applied at the mill typically leaves the ends of the pipe clean, for proper welding). Once this is finished, the entire coating of the pipe is inspected to ensure that it is free from defects.
4. Lowering the Pipeline
Once the pipeline is welded, bent and coated, it is lowered into the previously dug trench. Specialized construction equipment uniformly lifts the pipe and lowers in into the trench. Once lowered, the trench is filled carefully, to ensure that the pipe and its coating do not incur damage.
5. Hydrostatic Testing
After the pipe is in place and covered, a procedure known as hydrostatic testing begins. This process tests for leaks or fissures in the pipelines by using running water placed under pressures that far exceed the pipeline’s normal operating standards. Hydrostatic testing ensures the pipeline’s safety before natural gas is placed in the line.
6. Land Restoration
The final step in the construction process is land restoration. Extensive efforts are taken to restore the pipeline’s pathway to its original state, or to mitigate any impacts, environmental or otherwise, that may have occurred during the construction process.
Land restoration typical includes replacing topsoil, grass, fences, irrigation canals, trees or anything else that may have been removed or damaged during the construction process. Pipeline companies attempt to return the surface of the land as closely as possible to how it was prior to construction.
7. Directional Drilling or Boring- An Alternative Construction Method
At times, directional drilling (directional boring) is used when trenching is not practical. Directional drilling is a construction process that allows pipe to be installed underground without digging trenches. It is often more efficient than cutting trenches and can minimize environmental disruption.
When using directional drilling, or boring, to lay pipe, a back reamer is attached to the end of the bore and pulled back with the pipe. Boring employs a highly sophisticated computerized system to ensure accurate drilling and pipe placement in one pass.
Safety Measures
In order to ensure the efficient and safe operations of natural gas pipelines, companies adopt the following safety steps:
- Aerial Patrols: Planes patrol the pipeline route to identify pipeline encroachments, one of the most common threats to pipeline safety.
- Pipeline Markers: These signs, which may be black, red, white or yellow, identify the general location of the pipeline; they are placed along the pipeline route and at intersections and waterways.
- Gas Sampling: Regular natural gas testing provides insight to its quality and may indicate early signs of corrosion.
- Preventative Maintenance: This involves the testing of valves and the removal of surface blockades that impact the operator’s ability to inspect the pipeline. In addition, gathering pipeline operators often add inhibitors that coat the inside of the pipeline and use equipment to regularly scrub the inside of the pipeline.
- Leak Detecting Equipment: Equipment, such as smart pigs, can test pipe thickness, roundness, check for signs of corrosion and detect a possible leak or defect along the interior of a pipeline. In addition, pipeline personnel check for visible signs of leaks or corrosion during regular aerial and foot patrols. Pipeline operators also monitor their pipeline operations 24-hours a day, every day using technology connected to their operations control centers.
- Participation in One-Call: One-Call is a state-specific program designed to alert a pipeline company that excavation activity is planned near its pipeline. One-Call is a free service and can be reached by dialing 811.
Are pipelines safe?
Pipelines are, by far, the safest method for transporting energy products. Together the Pipeline & Hazardous Materials Safety Administration – a division of the U.S. D.O.T — and the Texas Railroad Commission are responsible for regulating pipeline operators and for inspecting and enforcing gas pipeline safety requirements in Texas.
Who should I contact to locate pipelines in my area?
If you are planning to dig twelve inches or deeper for any reason, contact your local One-Call organization by dialing 811. One-Call will alert the utility companies in your area to come, free of charge, to mark the utility lines on your property.
Do all natural gas pipelines contain an odorant?
Some pipelines contain an odorant, called mercaptan, which smells similar to rotten eggs, and some pipelines do not. Existing state and federal regulations determine whether or not a gathering or transmission pipeline should include odorant In some cases, depending on the intended use of the gas, it is not possible to add odorant to a pipeline. The primary use of odorant is due to gas being utilized in enclosed areas such as homes, so that it can be quickly detected before it reaches ignition sources. The odorant is not normally used in gathering and transmission lines because those lines are vented to the atmosphere for maintenance activity, in process controls, and the odorant would hinder treating/processing abilities. Natural gas in an open environment normally dissipates quickly into the atmosphere which eliminates the need for odorant.
Is odor the best indication of a pipeline leak?
Odor can be one of several indications of a potential leak. If a distribution pipeline is leaking inside your house, odor is often the quickest way to detect the leak. But if a leak occurs on an underground transmission or gathering pipeline located outside, sight and sound are often more reliable ways to detect the leak.
If you live or work near a transmission or gathering pipeline, it is important to know the other, often more obvious, signs of a potential leak including: distressed vegetation (such as grass) near the pipeline, dirt blowing in the air and hissing or roaring sounds.
Compressor Stations
Usually placed at 40 to 100-mile intervals along a pipeline, compressor stations push natural gas along the pipeline route by compressing gas to 100 times the normal atmospheric pressure using a turbine, motor or engine. Recent technologies incorporated in the past few years have made great strides in minimizing sound emissions from station facilities.
Compressor stations usually contain a liquid separator. Though natural gas in pipelines is categorized as “dry”, it is not uncommon for some water and hydrocarbons to condense in transit. The liquid separators are just another step to ensure that the natural gas flowing through the pipeline is as pure as possible.
Metering Stations
Metering stations are found along interstate natural gas pipelines. Pipeline companies use metering stations to measure all natural gas going into or out of the pipeline system.
To measure the flow of natural gas, metering stations use a variety of meters including orifice, turbine, insertion, ultrasonic and positive displacement meters.
Additionally, some metering stations also regulate pressure and delivery volumes. These stations, often called meter and regulator stations (M&R), are important to ensure gas is traveling within the specific pressure ranges the line was built to withstand.
Regulatory Oversight
Who regulates the gas industry?
The regulation of exploration and production of oil and gas in Texas is the responsibility of the Railroad Commission of Texas. The primary responsibilities of the Railroad Commission include preventing waste of oil and gas resources, protection of surface and subsurface water, and helping ensure interests of mineral owners. The Railroad Commission does not oversee or have jurisdiction for issues related to oil and gas exploration and production such as roads, traffic, aesthetics and sound, which are regulated locally, as are odors, leases, pipeline easements and royalty payments.
Who regulates natural gas pipelines?
The regulation of natural gas pipelines in Texas is the responsibility of the Pipeline & Hazardous Materials Safety Administration —a division of the U.S. D.O.T--and the Texas Railroad Commission. Together they regulate, inspect and enforce pipeline safety requirements.
Who regulates roads?
Texas Department of Transportation. However, most municipalities require road use agreements with additional stipulations, and counties may exert influence on the points of entry into a location affecting how roads are used.
Can I get a map of the pipelines that run through my neighborhood?
The best way to identify the general location of a pipeline near your home or business is to locate the pipeline markers placed along the pipeline route and at road and railway crossings.
The federal government also provides maps of transmission pipelines in your community. You can find this information by visiting the National Pipeline Mapping System at www.npms.phmsa.dot.gov. Currently, the NPMS does not include maps of local distribution or gathering lines.
