Question Your Beliefs About Vent Gas
March 3, 2015

Beliefs are very strong and control our world. Some beliefs should be questioned with time to help ensure we are on the right track. Beliefs about vent gas from oil and gas production facilities is one area to question beliefs. Storage tanks storing crude oil, condensate and produced water can result in the following "non-beneficial" effects:

  • Loss of hydrocarbon product
  • Increase in air emissions
  • Decreased profitability
  • Additional environmental risks
  • Less favorable public image

Vent gas is natural gas.

 

question your beliefs about vent gas management voc natural gas

Some beliefs and alternative beliefs regarding vent gas include:

Belief 1 – Vent gas is a waste.

New Belief:  Vent gas from storage tanks is product. 

Vent gas from storage tanks contains natural gas that has a higher energy content (BTU/SCF) than separator/sales gas. Based on the energy content, vent gas with BTU values of 1500 to 2500 can have a monetary value of 1.5 to 2.5 times the value of a typical pipeline natural gas that contains around 1000 BTU/SCF.  

 

Belief 2 – Vent gas is too hard to recover.

New Belief: Vent gas from storage tanks can be successfully recovered with a vapor recovery unit (VRU).

A properly sized and designed VRU for the application can reliably recover vent gas. The added benefit is that this dramatically reduces venting and flaring of natural gas. Also, using VRUs as process equipment can reduce storage tank VOC potential to emit (PTE) to ensure compliance with NSPS OOOO and various state VOC regulations. 

 

Belief 3 – Vent gas is invisible.

New Belief: Natural gas from venting is now easily detected using remote sensing leak detection technologies.

Infrared (IR) cameras are in common use now by industry and regulatory agencies for detecting leaks. Many new technologies are being developed or re-purposed to detect leaks and venting of natural gas from O&G operations.  Some states require leak detection and repair programs (LDAR) for oil and gas production facilities. The EPA is now examining how NSPS OOOO might include LDAR for oil and gas facilities.

 

Belief 4 – Vent gas is not a big deal; just route it to a flare.

New Belief:  Natural gas venting and flaring of is getting much more attention now.

This focused attention includes the press, social media, non-governmental organizations and the government regulators (USEPA). Expect this scrutiny to increase with time. Visible flares hurt our industry's reputation, our message of proper stewardship of hydrocarbon resources and shareholder value. Routing vent gas that can be recovered and sent to a sales line helps with the effort to voluntarily reduce flaring.

 

Belief 5 – Vent gas is too hard to measure.

New Belief:  Using industry accepted meters, tank vent gas can be accurately measured.

Using methods that ensure the storage tank(s) are sealed and a duration that captures the cyclical flow of gas, correct data can be obtained to properly size a vapor recovery system for the tank vent gas emissions. Using calibrated meters that fit the application yields accurate results.

 

Belief 6 – Oversight compliance is not widespread. 

New Belief:  Regulatory inspections have increased using remote sensing methods.

Voluntary compliance is required and the basis of environmental regulations.  Inspectors have increased the use of technology to find leaks and ensure compliance with venting and flaring regulations. In addition to fines, regulatory actions related to VOC emissions are increasingly including a required reduction or “shutting in” of a well’s oil production until remedied.

 

Belief 7 – We do not have to do anything there is no enforcement. 

New Belief: Enforcement of air regulations is occurring now and increasing.

The reality is that regulatory agencies do have the tools (infrared cameras, gas detectors, vector analysis tools) to locate and track emissions and they are using the tools daily. In many states regulatory agencies mount cameras on small aircraft and fly over producing areas to identify and then notify operators of noncompliance issues. The enforcement of these regulations (in the form of fines) has been increasing over the last ten years and show only a trend of increasing. 

 

Belief 8: Management is not concerned with vent gas emissions so I am not going to worry about them. 

New Belief: Most O&G senior executive are very concerned about the vent gas issues.

With the public taking a greater interest in environment issues as well as recent high profile accidents in the O&G industry, the majority of senior executives are very concerned about sustainability and public perception. The technology to identify and track emissions sources reside not only with the regulatory agencies and the oil companies, but with public groups, news agencies and environmental advocates. Today, it is very common for the public to make a judgment of culpability prior to the facts being reviewed.  This liability can impact investor confidence, stock prices and company valuations. With the current commodity prices, executives want ways to reduce liabilities and costs. Environmental liabilities can become very expensive very quickly and can have a huge impact our company's profitability and sustainability. 

 

Belief 9: All compressors are the same and the cheapest VRU will do the job.

New Belief: A reliable system requires the proper VRU for the specific application.

VRUs wet gas service typically use oil flooded screw and vane compressors because they work over the long term. Packages designed for dry gas applications (often very low cost reciprocating compressor units) will not do the job for high BTU wet gas service that storage tanks emit as the lubricating oil quickly becomes compromised and the isolation packing fails, giving rise to gas blowing uncontrolled onto the skid. While there are multiple types of compressors that can handle this very wet, rich, low pressure and low volume gas stream (i.e. rotary/sliding vane, rotary screw and some specialized reciprocating compressors), generally the low cost, dry gas / well head type machines will fail in a very short time. One really needs to review the overall package design and ensure the package is “fit-for-purpose”.  Most wellhead and dry gas compressor packages do not meet the minimum definition of a VRU by the USEPA or most state agencies.

References

  • USEPA Natural Gas STAR Program
  • 40 CFR 60 Subpart OOOO – Standards of Performance for Crude Oil and Natural Gas Production, Transmission and Distribution
  • HY-BON IQR Services
  • HY-BON VGM

 


 Vent gas management is HY-BON’s business. Using our 60+ years of experience and suite of products and services we can help your company recover value vent gas, increase facility profitability and reduce environmental liabilities. Call us now.