Research Of Seismic Acquisition Technology At Zhuanghai Area

This thesis aims at improving seismic acquisition quality and seismic exploration precision in shallow marine and beach seismic area through systematic research on the basis of shallow marine and beach seismic exploration project in Zhuanghai area. Aiming at the specific complexity of surface and LVL structure in shallow marine and beach area, through the analysis of characteristic of shallow marine and beach seismic acquisition, researches have been done on shallow marine and beach seismic acquisition source, optimizing of explosion parameters, geophones, optimizing of geometry, positioning accuracy etc. Main object of this thesis includes solving the problem of seismic wave explosion and receiving in shallow marine and beach seismic area to improve quality of seismic signal as well as solving the problem of positioning of source and geophone during the operation to guarantee effective stacking of seismic data.Following development and result have been achieved in this thesis: (1) LVL structure investigation appropriated to beach and shallow marine area has been formed through combined application of shallow layer multi-channel seismic technology, borehole sampling, cross hole uphole and uphole survey, as a result LVL data in shallow marine and beach from land, transition zone to very shallow marine has been got. The achieved LVL model has also been used on guiding the optimizing of field seismic wave explosion and receiving parameters, on guiding the optimizing of delay-and-stack source parameters in order to improve main frequency of seismic wave, also it is helpful for the analysis of LVL affection to seismic wave and attenuation regularity of seismic wave in LVL in order to provide accurate static correction data for seismic processing. (2)Technology of accurate positioning of geophone in water had been researched in order to solve the problem that geophone position may be changed in water because of the water stream. Through combined use of sonar positioning and first break positioning, location of geophone can be accurately positioned, so that raw data quality and precision of seismic exploration have been improved. (3)Delay-and-Stack source has been developed on the basis of explosive explosion theory, through changing of structure and explosion model of normal explosive, frequency band of seismic wavelet has been widened, S/N of seismic data has been improved, difference between explosive source and airgun source has been minimized.(4) Respect to the receiving of seismic wave,"Land hydrophone"has been developed in order to minimize difference between seismic signal received by normal geophone in land and hydro phone in water. On the other hand variety of geophone coupling tool have been developed to achieve good coupling of geophone especially in silt area in order that surface vibrating be recorded factually which result in the improving of exploration precision.