2008 CSHM • Passive Sonar-Based VF and GVF Meters
Use of Non-Contact, Passive Sonar-Based VF and GVF Meter for Improved Sour Water Reinjection Measurement
Sonar flow and gas volume fraction technology employs an array of sensors that are wrapped around an existing process pipe, requiring no coupling gels or alignment. The sensor element is connected to a transmitter which consists of a powerful, digital signal processor that processes coherent pressure disturbances, naturally occurring in process pipes, to deliver real time measurements of volumetric flow and entrained gases in the process fluid (gas volume fraction).
Accurate measurement of produced sour water (water containing hydrogen sulfide) is a critical component of effective oil field management. An approach is presented which enables accurate measurement of sour water reinjected (disposed) into individual wells through the use of non- contact, sonar-based volumetric flow and gas volume fraction technology. Utilizing passive sonar, signal array processing to measure volumetric flow rate and gas volume fraction of the process fluid helps enable operators ensure efficient resource and asset utilization, accurate material balance reporting, and the health and safety of its employees.
Some of the benefits described in this paper will focus on the non-contact and entrained gas measurement features of the sonar technology. For example, because the sensor element is wrapped around the existing process pipe there is one less potential path for dangerous emissions to escape. In addition, the flow element can be installed or removed while the wells are flowing so there is no need to interrupt production, allowing for increased asset uptime and utilization. By providing a real time measurement of entrained gas in the process fluid, the sonar process flow monitoring system can be a leading indicator of decreasing back pressure so that the appropriate operator action can occur. Because an accurate real time measurement of gas volume fraction is maintained, a true liquid flow can be measured to produce more accurate measurements and material balances to the operating company and regulatory agencies. Finally a case study describing the practical application of the passive sonar technology by an Alberta oil and gas production company committed to employing innovative solutions to help improve heath, safety and environment will be presented.