Cracking Very LF Land Seismic Acquisition – A Step Change

The emission and recording of very low frequency land seismic data provided greater potential for imaging the deep target, and for enhancing potential of applications such as Full Waveform Inversion. Nevertheless, there were several recognised or perceived limitations to producing low frequency using conventional vibrators and conventional 10 Hz geophones. Additional challenges in producing low frequency data included vibrator phase and distortion control, and the impact of similar amplitude low frequency noise associated with the acquisition environment. In March 2011, Petroleum Development Oman (PDO) commenced acquiring seismic data using conventional vibrators and 10Hz geophones with a non linear, customised 9 sec sweep with bandwidth 1.5-86 Hz. Very low frequency seismic acquisition is now ongoing on two high production DS3 land seismic crews in the Sultanate of Oman. Prior to embarking into low frequency acquisition, PDO and its contractors carried out a number of source tests, keeping in mind quality and productivity requirements. In this paper we will be presenting tests results to include harmonics appearance and to demonstrate the presence of the low frequency land data. We also discuss the impact and mitigation of external noise sources of similar low frequency.