The application of long-range GPR for seismic static corrections

A particularly challenging parameter for petroleum exploration in aeolian desert environments is the thickness of the low velocity layer (LVL), which can vary laterally due to numerous reasons, including variations in weathering depths or the presence of palaeochannels. Traditional methods of mapping the LVL, such as uphole seismic surveys, offer precise depth information but at disparate points. Although these environments are commonly classified as hyper-arid, the imaging depth requirement for these seismic static corrections is well beyond that of commercial GPR instruments. It is also known that the interdune corridors consist of electrically-conductive evaporate calcrete layers, which commonly extend beneath dunes. However, it may be possible to construct a powerful low-frequency radar which could penetrate the required depths, given ideal conditions. Herein are presented examples of a series of test surveys from the Sahara Desert with two real-time sampling radar systems, centred at 25 MHz and 10 MHz, designed to penetrate as deep as possible into aeolian environments to image seismic static correction depths. These preliminary results suggest that, if the correct environment is selected, long-range GPR can offer some insights into LVL geometries.