Development of a Novel Infrared Detector for Improved CO2 Subsurface Sequestration Monitoring

Low cost and accurate monitoring of sequestered gases such as CO2 is critical to ensure that these gases are not reentering the atmosphere. Management requires, in part, improved atmospheric and ground monitoring of these greenhouse gases through sensors capable of measuring the subsurface flux, concentration and the carbon isotopologues of CO2 with high accuracy. These Monitoring, Verification and Accounting (MVA) tools needs to meet very strict requirements including; (a) the ability to differentiate between natural and anthropogenic CO2; (b) sensitive to the location of injected CO2 and any potential release; (c) robust enough for operating in harsh environments; and (d) capable of monitoring requirements across the range of storage formation(s), depth)s), temperature(s), pressure(s) and porocities. Statement of How this Problem or Situation is Being Addressed The ability to differentiate between natural and anthropogenic CO2 emissions requires detectors that can differentiate CO2 isotopologues. In this program an ultra-sensitive infrared CO2 sensor system, designed to optimally operate at 4.36 m, where both CO2 isotopologues are optically active has been constructed and will be testing in actual MVA monitoring situations. The sensor is able to accuracy and rapidly measure the concentration and isotopic ratio of CO2 isotopologues, and thus determine the gas origin. What was Done in Phase I/Phase II project In the Phase I and Phase II program, an infrared detector optimized for detection at 4.36 m was designed, fabricated, and tested. This detector was used in a subsurface CO2 gas monitoring system first developed at Montana State University. This upgraded system can detect the different isotopes of CO2 and was field tested at the Montana State University’s Zero Emission Research Technology (ZERT) subsurface CO2 field site where the 13CO2 and 12CO2 isotopes where monitored. Total gas concentration and isotopic ratio was measured successfully. What is Planned for Phase IIB The system developed in Phase II will be re-engineered to make it more commercially producible. Wireless communication and multiple probes will also be added. The system will then be field tested in actual enhanced oil recovery and sequestration monitoring sites. Commercial Application and Other Benefits In addition to direct MVA applications, particularly monitoring of CO2 anthropogenic activities and sequestration sites, this technology can be readily translated to other applications including monitoring of other gasses that have absorption bands in the infrared.