​Noise Control in Drilling Operations

Noise from drilling operations can be problematic in areas with noise sensitive receptors nearby.  In the past, drilling operations were typically located in remote areas with few neighbours. Consequently, rigs were not subject to noise regulations.  The fact that drilling operations are not permanent also meant that it was relatively easy for operators to deal with sporadic noise complaints on a case by case basis.  When drilling and well service rigs moved into more densely populated areas, however, noise became a much more demanding issue.  Many municipal governments began restricting noise as the exploration and production of shale gas increased.  Adopting a noise control policy even when no regulatory requirements exist at a dig site is an approach more producers are taking to circumvent noise complaints and damage to community relations.

Horizontal drilling practices now allow for multiple wells to be drilled on a single well pad, requiring drilling equipment to stay on location for longer durations than in conventional operations.  Exposure to noise complaints from sensitive receptors has increased as a result.  Completion and well testing operations which follow the drilling phase also contribute to different and wide ranging noise levels.  

To determine whether a drilling rig will meet regulatory or organizational environmental policy requirements in a specific location, a noise propagation model should be used.  A noise propagation model takes into account the effects of topographical features of the area, seasonal meteorological conditions, multiple reception points, reflections, and obstacle interference that become overwhelmingly tedious to calculate by hand.  Once a noise propagation model has been developed for a certain type of rig, noise impact on subsequent drilling locations can be calculated with relative ease.  Additionally, if noise reduction is deemed necessary, alternate noise control measures and equipment orientations can be evaluated in order to control the cost of noise abatement.

 Noise model - mapping multiple drilling and well sites before mitigation.

Noise Control Measures

Noise control measures used for drilling operations have often been makeshift and ineffective due to their temporary nature. Quiet rigs are uncommon because they are not usually designed with environmental noise in mind. Diesel motors, mud pumps, emergency pressure reliefs, and mechanical drives are the main sources of noise concern on a drill rig.

Noise control measures will vary depending on site characteristics and regulations affecting the site location. By completing a noise impact assessment before the site is set up, acoustical costs can be minimized, as there are more options when choosing equipment and placement. In some cases, a simple upgrade of exhaust mufflers will suffice.  On sites with more stringent environmental noise control requirements, noise barriers, acoustic enclosures, and other abatement measures may be needed.

Once a complaint arises, mitigation options become more costly and difficult to install. Permanent barriers may be considered on sites where wells require frequent service or compressors are required. Other sites may use temporary barriers consisting of a coated canvas material hung on steel supports to a height of about 32’.  This approach reduces noise, but only by a minimal amount, and does not affect low-frequency noise. Placing permanent barriers, enclosing equipment and upgrading equipment exhaust silencers can also mitigate noise on completed projects, but retrofitting equipment and sites can be more expensive than designing them into the site plan.

Low Frequency Noise

Low-frequency noise can be an issue for drilling operations.  Low-frequency noise is not regularly stated in noise regulations but can cause extreme annoyance to neighbours and produce complaints. The difficulty with low-frequency noise is that it is normally not a constant sound but surfaces when there is a change in site conditions or equipment. Situations where noise only presents itself at night time, when the ambient noise level of the community decreases, are relatively common.

Low-frequency noise propagation can be calculated using a noise propagation model in conjunction with some supplemental acoustical engineering calculations. Barriers, particularly those used in temporary installations or made from plastic materials achieve little or no reduction in low-frequency noise.  Source treatments such as mufflers and equipment enclosures around motors reduce low-frequency noise emissions, and combined with site selection and equipment orientation, are cost-effective means for reducing the occurrence of noise complaints.

                                        Drill Rig Muffler Before                                                                        Drill Rig Muffler After

By having a qualified acoustical consulting company complete an initial site survey and model operating conditions, you will be able to implement a noise management plan at each of your drilling sites in the most cost-effective way.

If you already have issues at your site, answers to the following questions provide cost mitigation measures that may help:

1. Do all your engines have exhaust silencers?

2. Do all your enclosures have ventilation silencers?

3. Can you minimize the number of generators you run at certain times of the day?

4. Are your operators keeping enclosure doors closed?

5. Can you re-arrange your operations’ schedules to cut down on over lapping noises?

6. Is there site related traffic congestion?

A good neighbour policy is important for today’s oil & gas industry. Putting measures in place beforehand can not only save you money in retrofit costs but can also reduce the likelihood of complaints from landowners. A qualified acoustical consulting and engineering company can help you achieve a complaint-free drilling program.