Design And Installation Of A Permanent Three-Component Geophone String At An Aquifer Storage And Recovery Site; Beenyup Western Australia

Abstract

Seismic reflection is taking on a more prominent role in the world of hydrogeology. Seismic techniques such as Vertical Seismic Profiling (VSP), now common in the petroleum industry, must be suitably adapted for new shallower applications (i.e. Hydrogeology). Managed aquifer recharge (MAR) and aquifer storage and recharge (ASR) have become important tools for groundwater management and require a higher standard of investigation, especially in the near well setting. For relatively shallow injection zones the maximum rate of injection is dependent on a number of factors including; depth to the injection zone; distribution of hydraulic conductivity and the integrity/strength of layering above the injection zone. Vertical Seismic Profiling (VSP) has potential to recover detailed information about near well hydrostratigraphy. We have designed and installed a permanent three-component (3C) geophone string proximal to a high volume injection bore at the Beenyup trial aquifer storage and recover site; Perth Western Australia. The deepest geophone is 280 m below ground level. The string consists of ten vertical axis geophones and six tri-axial geophones. The geophone array spans up to five distinct lithological units including major aquatard zones (e.g. the Pinjar Member of the Leederville Formation) and the main aquifer zone (i.e. the Wanneroo Member of the Leederville Formation). In combination with a 3-D seismic survey the VSP data will be used to recover detailed hydrostratigraphy for input to hydraulic flow and reactive transport models for the site. The geophone string will form permanent research infrastructure for a number of 3-D and 4-D VSP experiments to be conducted during the Injection trial at Beenyup. We detail the processes used to design and install the Beenyup geophone string and provide examples of the 3C VSP data obtained.