Void and alteration zone detection on the top of a limestone unit for a gas complex

Heavy and sensitive infrastructure construction requires advanced knowledge of the underground features. The presence of limestone in a gas complex called for the recognition of possible sinkholes or alteration-prone areas.

A 10x10m grid was acquired on 1km² and the detected anomalies were detailed through a smaller grid (5x5m)

Microgravity data correlated adequately with refraction seismology results, which led to a precise overall geological interpretation of the site.

3D inversion of the observed gravimetric anomalies allowed the creation of bedrock depth maps. The deepening of the limestone top layers are very well correlated to refraction seismology.