Seismic exploration of potassium salt in Dalangtan-Heibei concave of Qaidam Basin and its preliminary results

The potassium salt resources are abundant in Dalangtan-Heibei concave in northwestern Qaidam Basin, but the shallow folds of conventional seismic detection technology are insufficient, affecting the imaging quality. In order to detect the fine structure of potassium brine reservoir in Dalangtan-Heibei concave, the authors carried out high-resolution reflection seismic detection. The high-quality seismic data and preliminary exploration results were obtained in this area, through the acquisition parameter optimization test and effective data processing. ① The acquisition scheme of small trace spacing, long array, high folds, vibroseis excitation with strong energy and broadband is conducive to obtaining high quality original data. ② The linear interference is effectively suppressed through multiple iterative dynamic correction and F-K filtering, and shallow effective waves were preserved to avoid fault illusion. The imaging quality was significantly improved, and the geological structures were effectively deciphered. ③ The seismic data reveal that the top of the deep gravel type halogen reservoir is in angular unconformity contact with the overlying strata, and the two ends of the reservoir are controlled by two faults. The reservoir space is composed of unconformity surface, faults and strong reflection interface at the bottom, which gradually peaks out in a triangular area from south to north, suggesting that the triangular reservoir may be a favorable storage space for gravel type potccssium-containing brine. In this paper, the effective seismic detection technology was used to successfully reveal the underground structural framework, and the characteristics of the formation structure of the potassium brine reservoir were finely deciphered. This work could provide geophysical basis for the exploration of the characteristics of the potassium brine reservoir, and is of significance for the further study of the gravel type potassium-containing brine.