Experiment and analysis of the best acquisition parameters for deep seismic reflection profiles in Huahai Basin

The deep seismic reflection profiling is a pioneering technique for detecting the deep structure of the crust. It can obtain the reflection fabrics of the Moho and the upper mantle, and hence is an effective method for revealing the lithosphere structure. The Huahai Basin is located in the western part of the Hexi Corridor basin, which is the intersection area of different tectonic units. The stratigraphic development is relatively complete, but the degrees of excavation and development are quite different. Except for the large area continuous distribution of the Cretaceous strata, the strata of other epochs are incompletely exposed, and are often manifested as residual debris damaged by division of intrusive rocks. In order to determine the suitable acquisition parameters for deep seismic reflection in the Huahai Basin, the authors conducted a pilot experiment before the collection, in which the small, medium and large TNT explosives were fired, and wells with different depths were drilled to make comparison. The parameter comparison was preferred, and finally the optimized acquisition parameters were obtained. In the small TNT explosives experiment, the reflection information obtained by the 36 kg dose is not as rich as the information obtained by 48 kg and 60 kg dose, and the results of 48 kg and 60 kg doses are clearer in the clarity of the MOHO reflection, with the single well excitation better than the combined well excitation. In the experiment of medium and large TNT explosives, the contrast of different combination wells does not show much difference. As the dose increases, the excitation energy increases, and the interference wave energy such as surface wave and refracted wave also increases. The interference wave energy of the small TNT explosives is the weakest, but has the most abundant reflection information. The interference waves of he medium and large TNT explosives are more developed, but the middle-shallow reflection information can also be obtained through the noise-suppressed processing.