Next Generation Broadband Land Acquisition

Abstract

The acquisition of broadband full azimuth surveys in a desert environment requires the application of several new technologies. These technologies can be divided in three main fields: the seismic receiver, the seismic source and the processing algorithms. We will discuss these new technologies, and show that the developments towards high channel counts and low frequencies are intimately related. Hence, an integrated approach is required to make optimum use of new emerging technologies. We also show some applications of the technology, demonstrating the value that these novel acquisition techniques can provide.Source -Desert surveys almost exclusively use Vibroseis as a source. Over the last two years, the use of low frequencies in onshore seismic acquisition and processing has become more and more a routine practice. However, the emission of low frequencies by seismic vibrators is far from trivial and required a number of new technological developments and field tests. We will discuss the developments in vibrator technology, the limitations that are still in existence today and possible future developments.Receiver -Current developments in land seismic acquisition show a trend towards higher channel counts and increased bandwidth. In addition, the increase in use of single sensors provides potential for acquiring higher resolution data, and improved signal preservation at the higher frequencies.For broadband desert surveys, to significantly improve data fidelity, data sampling needs to be much improved by much increasing the channel count and including very low frequencies down to 1Hz. Shell is investing in the development of broad band land sensors that records to very low frequencies (Ͻ 1Hz) and are cost-effectively scalable to 1 million channels. Single, light weighted, sensor systems will be much cheaper and faster to deploy, with less staff and lower HSE footprint. We will describe the status and report on recent field trial in the Middle East.Both the full azimuth aspect of the surveys and the low frequency content require the application of dedicated processing algorithms. These processes vary from a geophone amplitude-and phase correction early in the processing chain, to Full Waveform Inversion and processing techniques that account for azimuthal variations at later stages in the processing. Applications of broadband full azimuth technologies will be shown, demonstrating the benefits that a bandwidth extension can provide to the seismic data in terms of increased resolution and structural definition.