Situation: A large gas gatherer and processor in the DJ Basin was experiencing frequent high oxygen events on its system. The interstate pipeline taking gas from the gatherer’s processing plant had an oxygen limit of 10 ppm in its tariff specifications, began to actively enforce it, and at one point refused to take gas until the oxygen level was back below the 10 ppm limit. Consequently the gatherer began taking actions on its system to find the sources. This was complicated by the erratic and short-term nature of the oxygen events.

As a result of the inability to positively identify the source(s), the gatherer took the unprecedented step of asking all the producers to shut down any and all tank-mounted vapor recovery systems, including EcoVapor’s units. At this time, the oil producers were incorporating vapor recovery towers operating upstream of their oil storage tanks at low pressures to “deaden” the oil before it entered the tanks. That design was considered to be oxygen-free as it was in a low but positive pressure environment.

Despite banning tank-mounted vapor recovery systems and having producers adapt vapor tower systems, the gatherer continued to experience frequent oxygen events on its system. It became clear that other systems and processes were also introducing oxygen into the gas gathering system. Eight months into the ban, EcoVapor’s staff met with the gatherer with a plan to test our oxygen destruction technology and to clearly establish that EcoVapor’s units are as effective as advertised and prevent oxygen from entering the gas gathering system while recovering the high Btu, high value gas from the oil storage tanks.

A single, isolated pad site with eight multiple horizontal wells and conjoined storage tanks was chosen for the test. The site produced significant oil volumes with multiple loads being hauled each day, which, in turn, loaded the tanks with air every time they were emptied. This was a solid challenge for an EcoVapor unit.

Based on the VOC incinerator model and inlet pressure/volume curves, it was determined that an ERS 70 MCFD unit would best fit the application. The ERS 70 is equipped with a 34 HP EPA certified Zenith engine, which helped reduce the time and effort to obtain an air permit for the site. The ERS unit was tied in to the vent line leading from the storage tanks to the VOC incinerators, started up, and the tank pressures declined from 14 oz to 2 oz, extinguishing the flames in the incinerators in the process.

The ERS onboard oxygen analyzer records data every 10 seconds. During the initial 30 day test, oxygen in the gas sales volumes averaged under 2 ppm despite frequent oil hauling and occasions where hatches were not closed immediately. For their verification process, the gas gatherer took samples of the gas coming through their sales meter and used a portable analyzer.

Summary: After five months, the initial test unit continued to deliver gas well with oxygen levels below the pipeline specification. A second ERS was then installed on a different site with the same level of performance.

Conclusion: Despite claims that vapor removal/recovery systems installed upstream of the oil storage tanks are in an oxygen-free environment, gas gatherers continue to see frequent high oxygen events. EcoVapor’s units are designed to recover gas known to contain oxygen and process the stream such that virtually no oxygen is delivered into the pipeline. Only ERS incorporates active oxygen destruction technology and calibrated monitoring systems that together allow all the flash gas to be recovered, not burned at the site and wasted.

Only ERS incorporates active oxygen destruction technology and calibrated monitoring systems that together allow

all the flash gas to be recovered, not burned at the site and wasted.

CASE STUDY

the pipeline’s perspective

Peter Mueller, CEO petermueller@ecovaporrs.com

www.ecovaporrs.com

EcoVaporRecoverySystems