The sound mitigation industry has come a long way over the past few years and is now offering a variety of technologies and equipment that are helping the oil and gas industry be good neighbors when drilling and fracing wells or placing compressor stations in populated areas. However, it wasn’t so long ago that sound mitigation options were pretty limited, especially in Texas and neighboring states.

            In fact, years ago, the oil and gas industry in many parts of the United States simply didn’t think too much about sound control. Public awareness and activism about noise pollution simply were not as prevalent as they are today. Governmental regulations and legislation on the subject were almost non-existent in some places. If noise mitigation was used on a well or compressor station in a populated area, the technology available was rudimentary and basically limited to some type of barrier.

            “Such barriers that were erected were normally made of simple plywood, hay bales, or sometimes they were mounded soil barriers called berms,” wrote Tyler L.A. Mose of Noise Solutions Inc. (www.noisesolutions.com) in a technical paper on the Evolution of Noise Control Technology. “This style of barrier works well for certain applications, such as for roadside acoustic barriers, but they proved quite fruitless in typical oil and gas industry applications,” Mose continued.

            Exceptions to this lack of sound control in the U.S. oil and gas industry could be found in California and other noise sensitive areas, where drilling and production sound control systems have been in use since the late 1970s, according to Don Behrens of Behrens and Associates Inc./Environmental Noise Control (www.environmental-noise-control.com).

            Today, sound control and monitoring options for the oil and gas industry seem to be continually improving and expanding into new areas of the United States – especially as gas shale plays take drilling and production into additional urban areas. Petrohawk Energy Corporation’s (www.petrohawk.com) Joan Dunlap said she believes the mostly-urban Barnett Shale play has played a big role in the improved options now available to the industry for sound mitigation and monitoring.

            “There are a lot of (sound) businesses around today that weren’t around before the Barnett,” Dunlap said. “So now we have not just one or two vendors, but we’ve got a lot to choose from and they’re competitive. That competition has spurred better products and pricing.”

            In fact, a plethora of sound mitigation and monitoring companies seem to be plying their services to the industry these days, across the United States and Canada, helping the industry meet regulatory requirements enacted on many levels, from local city governments up to the state and federal levels.

            “In urban environments, extra precautions to mitigate sound include using blankets around the engine, constructing sound walls around the natural gas drillsite and installing mufflers, as necessary,” according to Jerri Robbins, Chesapeake Energy’s (www.chk.com) public relations manager for the Barnett Shale. “Based on a sound survey, experts determine the design and placement of the sound walls, which typically remain until all operations are completed.”

            The sound walls Robbins mentioned seem to be ubiquitous on most urban drilling sites these days, with vendors offering them in various shapes, forms and materials. For example, Steve Kellenaers, president and chief executive officer of Acoustical Control Inc. (www.acousticalcontrol-inc.com), points out that his company designs sound mitigation systems to meet the requirements of individual sites or customer specifications.

            “These can be anything from temporary curtains to sound wall systems to complete enclosures,” Kellenaers explained. He added that it is important to design a system that not only mitigates the sound for the area surrounding a site, but also allows the equipment within the site to operate without interference because “downtime is expensive.” It is also important to design a system “that can easily grow with the expansion of a (compressor) station as production increases, and also can be downsized without affecting the remainder of the system, as production may decline.”

            Kallenaers described a few of his company’s particularly challenging sound projects. They included three compressor sites in New Mexico, one on a golf course, one next to a school and church, and one in a neighborhood, all of which had to meet standards of no more than a 2 decibel increase over the early morning ambient sound level measured at 200 feet. Another unique project the company undertook was camouflaging a sound enclosure for a mid-stream compression site in Flower Mound, Texas, in a building that resembles a country barn.

            Amazingly, many of those bulky sound walls or enclosures are now also portable.

            “Drilling is so temporary, so transient,” said Don Behrens of Behrens and Associates Inc./Environmental Noise Control (www.environmental-noise-control.com). “Everything we do has to be put up and installed in such a short order. We spend a lot of time trying to get more effective mitigation equipment that can be put up and put down and moved, while still being kept in good shape.”

            But portability was not one of the main concerns on a particularly challenging sound project that Noise Attenuation Construction (NAC, www.nacnow.net) did recently for a Williams Exploration & Production (www.williams.com) compressor station located near Burleson, Texas. The location has three large CAT compressor engines moving natural gas for Williams, as well as other operators. Although the site is located outside of the Burleson City limits and, therefore, not subject to the city’s noise ordinance, Williams still wanted to be a good neighbor and mitigate the sound for nearby neighborhoods, said Brian Jackson, project manager and acoustical consultant for NAC.

            “There is a brand new housing edition under construction in that area and to be a good neighbor, we went ahead and designed a sound wall for that site with the intent of meeting the city ordinance, even though it wasn’t in the city limits,” said Lucas Smith, environmental health and safety specialist with Williams. “It’s actually the largest sound wall we have in the Fort Worth Basin. We have three large compressors -- it’s one of our better producing areas, and we needed a larger wall just to mitigate the noise. The developer that was putting in the houses down the road was ecstatic when we started building that thing.”

            Murray Stacy, vice president of Shreveport, La.-based Sound Fighter Systems (www.soundfighter.com) recalls another compressor facility in the Barnett Shale that proved especially challenging for noise mitigation.

            “It involved a compressor facility with numerous 3600 series compressors sitting atop a large hill that was the dominant topographic feature in the area,” Murray recalled. “The compressors themselves were located at different elevations on the hilltop. And to further complicate matters, some of the site lay under an electrical easement, limiting the height of any potential sound wall enclosure. Working extensively and closely with the operator and the utility company, we were able to design a multi-section, staggered LSE (absorptive) noise barrier that ranged in height from 8 to 25 feet, which significantly reduced noise levels downslope to the affected receivers.”

            Sound Fighter manufactures its barriers from absorptive, sound-dampening materials designed to eliminate sound waves that hit them, rather than reflecting the waves in a different direction, according to the company.

            Noise Solutions Inc. also does quite a bit of work creating acoustical buildings and other enclosures for compressor stations, pumpjacks, heavy oil top drives, and other wellhead compressor-type applications. Their products typically involve acoustically treated buildings that mitigate the noise from the source, before it reaches the environment.

            “These allow for efficient operation of compression equipment while maintaining a cool interior, maintaining the acoustical integrity because doors and windows can remain closed,” according to Natalie Wilkinson-Houghton of Noise Solutions. In addition, these enclosures can be designed to blend into the surrounding area.

 

            Of course, sound walls and compressor enclosures are only part of the picture these days in the sound mitigation business. Companies are using everything from computer modeling to determine the best way to place a rig on a site for the least noise impact to conducting sound surveys of the ambient noise level on a site before construction even begins on the drillsite, and then 24-hour monitoring and recording of sounds at a site after work begins.

            “When you get into a sensitive site, where you’re really concerned about making sure you’re compliant, it is always valuable to do an analysis up front. Like anything else, it’s all about planning,” Behrens said.

            In fact, Fort Worth’s ordinance, after which many other municipal ordinances have been patterned, requires an initial 72-hour sound level survey (including one weekend day) to establish what the current average sound levels are in an area before gas well drilling begins, according to Kristy Eidsness with Behrens and Associates Inc./Environmental Noise Control’s Aledo, Texas office. Eidsness maintains a database of local noise control ordinances in Texas. The beginning, “survey” level of sound in the area will be used to determine what the allowed daytime and nighttime sound levels will be. The “working” levels may not exceed the ambient noise level by more than 5 decibels during the day, from 7 a.m. until 7 p.m., and only by 3 decibels during the night, 7 p.m. until 7 a.m. Fracturing, which can be quite a bit noisier than drilling, is allowed 10 decibels over the ambient level during all hours of operation. The operator is held to these levels at the nearest “protected use” receiver’s (for example, a neighboring residence) property line or from the closest exterior point of the protected use structure, such as a church, Eidsness explained.

            Once a preliminary sound level survey is completed, the Fort Worth ordinance, and those of some other cities, requires that the operator must submit a noise management plan that provides the following information, according to Eidsness:

1.    Identify operation noise impacts

2.    Provide documentation establishing the ambient noise level prior to construction of any well head, compressor or compression facility; and

3.    Detail how the impacts will be mitigated (if sound walls are required and if so, what height is needed to keep the site in compliance), specific site characteristics shall be considered, including but not limited to:

a.    Nature and proximity of adjacent development, location, and type;

b.    Seasonal and prevailing weather patterns, including wind directions (wind can be a large factor in sound levels since wind can carry sound and can create sounds around the vicinity of the meter, such as leaves brushing, trees moving, etc.)

c.    Vegetative cover on or adjacent to the site; and

d.    Topography

            In addition, the ordinance states that if a protected use, such as a residence, church, hospital, etc. is located within 600 feet of a site, continuous sound level monitoring is required to ensure the site is in compliance at all times.

            This provision also has generated business for the noise mitigation companies, which often contract to take care of the sound monitoring for operators. For example, Behrens/Environmental Noise Control places a sound level meter on the site that is hooked up to a cellular modem which allows clients remote access to the sound level data at any time. In addition, on-site audio is recorded at the meters 24 hours a day.

            “This means that, not only are we measuring sound levels that jump up and down, but our meters also record an audio file so, if we have a blip or increase in sound, we can play back the audio recording during that period and identify very specifically what’s causing that noise,” Behrens explained. “That’s important because, when you put a meter out, you have a lot of environmental things affecting your measurements,” including wind, storms, birds, cicadas, cats, dogs, airplanes, helicopters or even a motorcycle roaring down the street.

            “The first thing we do when we see an excedence in sound levels on a site is to play back the audio recordings,” Behrens continued. “Maybe 75 percent of the excedences we see in our continuous monitoring during drilling are generated from sources other than the drilling activity. Typically, on a daily basis, every day we submit a report of the sound levels and all the data. If there is an excedence, we must identify what causes that excedence – that’s where the audio recording comes in – and, in our report (that operators submit to the city government), say what’s been done to make sure it doesn’t happen again. That’s where this system is effective for cities. If you’re just collecting data and not utilizing it as a tool to ensure compliance, then it’s all just an exercise in futility.”

            XTOEnergy Inc. and Range ResourcesCorporation were among the first operators in the Barnett Shale to use the new technology.

            Other types of technology are enabling companies to operate more quietly in the first place, reducing the chances they will exceed allowable noise levels. Available products include sound dampening and noise control wraps, sound absorbing and sound reflective products, acoustical enclosures, noise control pipe wraps, baffles, sound deadeners, curtains, composites, barriers, air line silencers, and complete buildings for compressor sound reduction.

            Preliminary computer modeling of sites is also used to help identify the best way to place a rig on a site for optimum noise control.

            “Computer software lets us plop a rig down and spin it around because different sides of a rig produce different noise levels,” Environmental Noise Control’s Behrens said. “For example, the ‘V’ door is usually on the quiet side of the rig and the generator side is usually the noisy side. By orienting the rig in a way to keep the noise away from the side of the property that’s most sensitive, you can help yourself a whole lot. Just spin the rig 90 degrees or 180 degrees and you may have solved your sound problem. With modeling, we can play with the mitigation so instead of putting up a 32-foot wall, we might get away with less. It lets the operator optimize what they do for the best noise control at the least cost.”

            Sound mitigation companies continue to research new technologies that might improve their offerings. Behrens’ Environmental Noise, for example, is working with suppliers to try to develop a composite material made out of recycled tires that can be used to coat surfaces to stop clanging and banging-type noises often made by such things as pulling and dropping pipe.

            “One of the things that is most onerous in urban areas is the clanging and banging in the middle of the night, metal hitting metal,” Behrens said. “You can have a very quiet operation and somebody drops a piece of pipe for a nanosecond and it wakes everybody up. And the drilling rig is wet, it’s dirty, there’s heavy pieces of equipment that are abrasive. So it’s a challenge to find a material that will physically be able to stand up under those conditions.”

            Sound Fighter Systems’ Stacy reported that new materials and polymers are being developed that may be incorporated into high-performance sound attenuation products, which should improve current offerings by making them lighter, stronger and cheaper.

            “We have a full-time polymer materials engineer on staff who does nothing but research and test such new concepts,” Stacy continued. “Other conceptual treatments such as noise-cancelling technology hold promise, but are a long way from becoming practical tools for large-scale outdoor mitigation.”

            Another factor in creating quieter drilling sites is sometimes the drilling rig itself. Many urban operators are now using quieter new-generation rigs that simply generate less noise than older models. For example, Petrohawk’s Dunlap said that company is in the process of adding newer, high tech rigs and ultra-quiet rigs, including some Nabors Pace rigs and some Helmerich & Payne (H&P) Flex rigs to its fleet. In fact, Petrohawk is using one of the new H&P rigs at a sensitive site next to an elementary school in Bossier City, La. The Grayson 25H-1 well is the first to be drilled in Bossier City. The city council there has enacted a new local drilling ordinance which regulates noise and other drilling issues, and the ordinance is the first of its kind in the Haynesville Shale area of northwest Louisiana. The H&P rig #391 being used on that site, built and deployed earlier this year, features a computerized system that controls and optimizes multiple activities in the drilling process, allowing the driller’s attention to be focused on efficiency and safety, according to H&P.

            The rig’s automation makes it safer for workers on the site, plus it allows the drilling to progress more quickly, so the work can be done more quickly, allowing the site to be less disruptive to an urban neighborhood. The rig also can be moved more quickly, “so it’s just not as disruptive as the rig up and rig down of a typical rig,” Dunlap pointed out.

            A big selling point for a producer trying to be a good neighbor in an urban area is, of course, that the rig is also quiet.

            “We could sit on the deck of the rig and have a normal conversation – it’s that quiet,” Dunlap said. “It is amazing.”

            Juan Pablo Tardio, director of investor relations for H&P, explained how the rig can operate more quietly. “There are typically three sources of significant noise in a conventional drilling rig: (1) the engines that generate power for the rig, (2) the drawworks braking mechanism (corresponding to the hoisting system), and (3) pipe handling,” Tardio explained. “All three of these sources of noise are significantly abated in a FlexRig3 through the use of rig design improvements and advanced-technology equipment.”

            Even with the quiet rigs Petrohawk is using in the Haynesville, the company is using sound mitigation services from Eagle Environmental and working hard to keep the lines of communication open with citizens and local governmental representatives to ward off any potential problems. With the operations of Grayson 25H-1, Dunlap said, “Trucks must adhere to a certain schedule that prohibits them from coming in and out of that location during the hours for school drop-off and pick-up times. Noise from trucks is really what people tend to get bothered by, more so than the drilling rig. We’re also not going to complete, or frac, the well during the school session. Our plan is to complete the well around Christmas when school is not in session. We are a good operator and we’ve got a good track record, but you can’t be too careful.”

            As operators in the Barnett Shale have already experienced, there is often a learning curve for both operators and citizens in the world of urban drilling. Until people have experienced a drilling operation in their community first-hand, they often just don’t know what to expect, and concern about the unknown is not usually warranted by the reality.

            “I had someone call (from the Shreveport/Bossier area) who wanted to know if they should wrap their china when we fraced,” Dunlap said. “We’re about 12,000 feet deep here, but there’s a common misperception about what drilling and fracing entails. Community education takes time.”

            Folks from the Haynesville also may be surprised that the way the play develops in northwest Louisiana may not look as much like the urban drilling in the Fort Worth area as some might expect.

            “In the Barnett area, it’s a much more densely drilled program,” Dunlap explained. “In the Haynesville, wells are deeper and have a different drainage pattern. It will probably look a lot different in the Haynesville than in the Barnett to people on the surface with fewer wells drilled per section.”

            “Petrohawk has been exemplary in communicating and keeping the city administration informed with the activity at their site so that they can be monitored by the city during the drilling process,” reported Mark Natale, Bossier City’s public information officer.

            A few miles away in Shreveport, at least one neighbor has been pleasantly surprised with the lack of noise emanating from the drilling site next door to his home on Waterview Lane.

            Barry Box said his home is located about 1,000 yards from a state highway where traffic is coming off a bridge over the Red River. “The noise from that highway is higher than the noise from the well,” Box said. “Petrohawk has put up these sound barrier systems and they are very effective. The well is not bothering us at all. I don’t hear the trucks coming or going or anything. Not to say that we’ve never heard it – if we’re outside, it sounds like there’s something going on over there. But in the house, even at night when they’re working over there, we don’t hear anything. I lived in the oilfields when I was a child and there’s a lot of difference in the noise now and in the past on these wells.”

            Satisfied neighbors like Box make sound mitigation worthwhile for many operators and the technology enables them to comply with the regulations necessary for working in urban environments. However, sound technologies and equipment don’t come cheap.

            “Each sound issue is a unique situation depending on multiple factors from the type of sound sources to terrain and/or proximity to a receptor (business or homes),” explained William’s environmental health and safety specialist Smith. “Based on these factors, Williams has spent as little as $10,000 to facilitate the sound control to over $1 million. It’s all about being a good neighbor and ensuring compliance where it’s needed!”

            “It costs what it costs, but costs are competitive,” said Dunlap. “It’s part of doing business in that area and we want to be invited back. These are important wells to get drilled and it’s totally in our best interest to make things as smooth for people as possible.” By Pamela Percival, Editor.