Injection-induced Seismicity in a Natural Gas Reservoir in Hutubi，Southern Junggar Basin, Northwest China

Abstract:

Hutubi seasonal gas reservoir is located in the relatively stable Southern Junggar Basin, Northwest China. It served as a natural gas exploration field from 1998 to 2013, and was converted into a seasonal gas storage reservoir in June 2013. Utilizing a newly developed event detection method named the Match and Locate (M&L) method, we study the seismicity around the reservoir from 2009 to 2015. We detect over 700 earthquakes from 2009 to 2015 nearby Hutubi gas storage, with the largest event magnitude of M_L 3.6. On the contrary, only one probable event is detected during the year before Hutubi gas field began operational in 1998. More than 200 earthquakes are detected during injection operations conducted between 2013 and 2014. Most of these earthquakes can be grouped into two clusters, located within 1-3 km of the injection wells and exhibiting strong waveform similarity within each cluster. There is a short time delay (12 days) from the rapid rise of well pressure to the onset of seismicity. We suggest that those detected earthquakes are most likely caused by the gas injection of Hutubi gas reservoir.