Parameters optimization of seismic data acquisition for deep buried karst geothermal reservoir in sedimentary basin: A case study of the Niutuo geothermal field in Xiongan New Area

Deep heterogeneous carbonate reservoirs have become more and more important in the deep exploration of geothermal resources in China. The essential seismic exploration technology has many difficulties, such as serious attenuation of deep energy, low signal-to-noise ratio, difficult imaging of inner basement in tectonic uplift areas. In order to acquire high-quality deep seismic exploration data, a large number of vibroseis excitation parameters and geophone receiving parameters experiments have been received in a typical areas of the Central Hebei Plain in North China. On the basis of a large number of field experimental data, a qualitative analysis of the original single-shot records is carried out, and quantitative analysis is also carried out from the aspects of frequency band energy, inter-channel frequency, signal-to-noise ratio, etc., to study the parameter selection such as the number of vibroseis, sweep frequency, sweep length, vibration times, driving amplitude and geophone combination mode, which can affect the quality of the seismic data. In this paper, the field construction parameters for 2D seismic exploration of deep carbonate reservoirs in the North China Plain are optimized as follows: 4 sets of 28 tons vibrate 4–6 times, 75% driving amplitude, non-linear sweep (slope –3), 6–84 Hz sweep frequency, and 12 s sweep length. The quality of the single-shot records and data processing profiles are greatly improved after parameter optimization, which can be more clearly divided into the bottom interface of the Gaoyuzhuang Formation of the Jixian System and the top interface of the Archean Erathern in the Niutuozhen uplift tectonic area. The optimized seismic acquisition parameters are of certain reference and guiding significance for deep seismic exploration in sedimentary basins.