Research On High Precision 3D Seismic Acquisition Method In Front Of Altun Mountains In Qaidam Basin

Dongping Structure is located in front of Altun Mountain, the west part of Qaidam Basin, it is the third tectonic in the Yiliping depression subregion, which belongs to the western depression area of Qaidam Basin. This structure is in the uplift part of two big hydrocarbon-generation sags, Yingxiong Ling, the Mangya tertiary and Jianshan, the Yiliping Jurassic system.According to the seismic geologic condition and complicated saline land, this paper has made thorough research to seismic acquisition technique and statics method. The main achievement of High Accurary 3D Seismic Exploration suitable for the front of Altun Mountain has been initially formed, which greatly improved data quality of Altun forelands. This paper developed a study on optimal design of 3-D geometry, which is based on improving the imaging precision of target bed. The study analyzed the pre-stack migration attribute of different geometry in order to improve the imaging quality of target bed, it optimized geometry from three respects, fold number, Azimuth(receiving line numbers and the interval of receiving lines), shot line density. In the shooting and receiving part, the paper carried out an experiment based on shooting parameter and receiving parameter in complicated saline land, to study the consistency of shooting seismic wavelet of different kinds of ground surface and effectiveness analysis of high frequency suppression by different geophone arrays. The article also developed a analysis of explosion feasibility of controlled vibrator and comparison of geophone arrays in the saline land, based on the study of simulation effect on different well numbers, different velocity, lithology, combination patterns and different explosive dosage to dynamite source. According to the features of thickness violent changes in the low velocity layer of saline land, the paper carried out a comparative study of tomographic inversion near-surface modeling, model constraint inversion modeling, multi-information comprehensive modeling and comparative study of different offset refraction layered, in order to probe out a near-surface modeling method suitable for this area to improve the calculation accuracy of static correction. This paper made a comprehensive discussion on the practical application of these content, thus formed a series of seismic acquisition and static correction technique in special surface condition of Altun forelands, which will supply reliable technical support to seismic exploration in this area.