SUMMARY
The Ventbuster® is a surface casing vent flow (SCVF) testing device, in full compliance with Alberta Energy Regulator (AER) Directives 20 and 87. It is a built-for-purpose, point-source, quantification technology providing the industry with the only scientific vent gas measurement through its patented flow channel.
BACKGROUND
Prior to the Ventbuster®, low-pressured emissions could never be accurately measured with positive displacement and differential pressure meters. To overcome this shortfall, service providers fashioned a self-styled block and bleed technique to build up volume and pressure followed by a timed release to create a pseudo-SCVF rate. If rates and pressures are still too low, it is reported as too-small-to-measure and regulators call for an evaluation using a “bubble-test” protocol outlined in well abandonment directives. This “proof” for a positive SCVF test is where one or more bubbles are “observed” over a random 10-minute duration. This technique is proven highly susceptible to human misinterpretation and subjective reporting, which leads to recording erroneous positive or negative SCVF.
THE CHALLENGE
Ventbuster Instruments formulated the AER “one bubble in 10-minute” equivalent, under laboratory conditions, through the Ventbuster® and found that they could measure a bubble rate in millilitres/day. They could not manifest a bubble in the AER-directed “one-inch” of water below this rate over the 10-minute duration. The Ventbuster® accurately “detects bubbles” and with its ability to measure flow rates as low as 0.04 millilitres/minute is proven more than capable of detecting “one bubble in 10 minutes.”
CLIENT BENEFITS
Precision detection of “ultra-low” flow rates and pressures of diffusing CH4 leaking to the atmosphere from oil and gas surface casing vents.
Highly sensitive flow detection with unambiguous digital data transmitted for real-time verification.
No longer “guesstimating” if an actual vent flow exists using self-styled, vent meter contraptions.
Regulatory-compliant SCVF validation and reporting.
APPLICATION
Clients approached Ventbuster Instruments to solve conflicting positive and negative testing reports after using these other pseudo-bubble testing methodologies. They insisted on finding a tried-and-true confirmation test to ensure regulatory compliance of repaired leaking wells before moving on with surface reclamation. After testing and measuring upwards of 4,000 surface casing vents, leaking wells, and an array of facility vents across Canada and the USA, their technology has proven capable of measuring the once immeasurable, low-pressured gas emissions. With such precise and continuous flow rates, pressures and temperatures being digitally recorded and transmitted live to Ventbuster Instruments’ IoT platform and dashboard display, a true baseline SCVF can now be established.
PROBLEM SOLVED
Ventbuster Instruments discovered that with the sensitivity and accuracy required to detect and continuously measure ultra-low flows and pressures, various ambient and environmental field influences can play a critical role in altering absolute SCVF readings and often induce false SCVF readings. These influences were found to be:
Barometric pressure changes generate a variation in ultra-low flow rates over testing timelines, and they have also observed both positive and negative flows at the SCV assembly. Barometric pressure changes also cause variances in flowing vent pressures;
Solar or radiant heating and ambient cooling of the vent assembly piping causes expansion and contraction of the air/gas, inducing small flows or vacuum effects;
Wind passing across the exhaust of the SCV, can produce a low-pressure venturi effect, drawing air/ gas volumes out of the vent to which they have designed a muffler to counter this effect;
Relative atmospheric humidity can induce air/gas flows from the vent assembly;
Some speculate that tidal forces come into play, which may induce air/gas flows from the vent assembly;
The same influences hold true for bubble testing techniques whereby ambient temperature and pressure changes or environmental conditions affect the bubble rate observation, but there is no control of this phenomenon.
Further analysis confirmed that no thermogenic gases were produced when there was no appreciable rise in the recorded pressure build-up test after the flowing event. Conversely, with a positive recorded shut-in pressure build-up after the flow event, thermogenic gases were always produced.
CONCLUSION
With technology now able to “measure the once immeasurable,” the energy industry can identify unintended negative environmental impacts by avoiding mitigation of negligible emissions such as chasing bubbles and a false-positive SCVF.
MOVING TOWARDS NET-ZERO
Ventbuster Instruments customizes its equipment to measure a vast array of methane (CH4) emitters. Using the Ventbuster® technology to measure emission flow rates and CH4 mass volumes, assists not only in effective management but has proven invaluable in carbon trading and the carbon offset market. By taking on this responsibility to precisely quantify and acknowledge our carbon footprint, the energy industry and Ventbuster Instruments can make significant steps along the path to achieving net-zero.
For further information about Ventbuster Instruments and their technology, please visit www.ventbusters.com. Gain insight into their technology, its function and deployment and review technical data sheets and other information documents.