The Research On Seismic Data Acquisition Method For The Thrust Block Formation Belt At Mountain Front In Yanqi Basin

Build from base-dish of Haixi drape in Nantianshan Mountain, Yanqi Basin is a compound basin in zhongxin.It is hardly modified by Indosinian, Yanshanian and Himalayan movement; the structure race is very complex. The boundary fault area is located in the west of basin. as it is near the deep source of oil, it possess special oil reservoirs involved in boundary fault with a good oil exploration future. The area is mainly covered with bold rock and Gobi, the near surface condition is bad for shooting & receiving; the existence of nappe structure below the ground makes the oil exploration hard. Though a series of former seismic explorations have been under carried out, the problem of nappe geologic structure imaging is still not resolved; at present, the area exploration for oil has not got a breakthrough.The target of the research on nappe structure seismic exploration method is that by studying the problems of the former seismic data; applying the new seismic exploration technology & method, to search a data acquisition idea which will be adopted in further re-exploration; by application of result of research, to improve the quality of seismic data, to line out the layout of faults and configuration of section, fault nose and block; to line out the distribution of sandstones and structure–llithology traps, meeting the need of further seismic exploration .Aiming at the problem of former seismic data, the article took a outstanding research in two aspects. Firstly, made a overall simulation test on shooting parameters, receiving parameters and acquisition geometry that affects seismic acquisition quality. Secondly, applying the acquisition parameter demonstrate and forward modeling software, built near surface geophysical model to design the shooting parameters; built physical data model and 2D deep model to examine the acquisition former geometry for finding its fault. By the research of shooting parameters, receiving parameters and acquisition geometry, discovering a set of new seismic exploration method suited the area; improving the quality of seismic data to meet the need of further geological research.The research includes :(1) analyzing the former seismic data, examining its acquisition geometry(2)applying the acquisition design software, based on the geological target model practically in ray tracing method ,studied the ray refraction from the downthrown block of thrust block formation, designed a reasonable acquisition geometry(3)took a detail research for near surface structure, particularly at mountain front area; built up accurate near surface model structure which will be used in designing of shooting & receiving parameter and static corrections(4) took a research for shooting parameter(hole depth, quantity of dynamite per hole, dynamite type, shooting matter ) in various of near surface conditions, designed suitable shooting parameters in different surface conditions, ensuring the energy and frequency width of seismic data, ensuring the data quality in S/N& resolution .By the research of seismic exploration method for the thrust block formation belt at mountain front in Yanqi Basin, primarily formed a set of new seismic exploration method suitable for the hereto, which has wide worth of application. The practice result showed that S/N & resolution of new seismic sections which applied in the result of research has improved contrast former data, obtaining a distinct geological result. The article gave some suggestion and pointed out the new idea for future research.