Research And Application Of Borehole And Surface Combined Seismic Exploration Technique

Borehole and surface combined technique is a new exploration method which combines surface seismic exploration with borehole VSP. This method realizes data's synchronous acquisition and processing .It can get high precise seismic data.through combined processing and interpretation to increase S/N and resolution of target stratum.In research on acquisition method, recording geometry and operation parameters were determined on the basis of geologic model, high S/N and resolution acquisition data were obtained.in research on processing method,higher precision imaging section were got. the dominant frequency of data was increased 15-20Hz,the bandwidth of data was increased 20-30Hz;in research on interpretation, geologic horizon could be calibrated accurately,10m thickness of stratum could be recognized, hydrocarbon development evaluation was more accurate.The operation procedure of borehole and surface combined method was as follows: the instrument was fixed at a certain depth of the borehole section, then the seismic source was moved in designed shooting direction.data were recorded synchronistically on surface and in downhole. The advantage of this method was convenient for the transmission wave prospecting,obtainning good results of common-depth-point stack, studying complicated structures easily.In this paper,acquisition parameters were demonstrated in detail,the acquisition data was analyzed in detail, the accurate productive limit was provided and reservoir type was determined,vertical and horizontal resolution were increased.The results obtained and works completed in this paper including: Precise velocity data and time-depth relations in borehole B282 were obtained,which provided parameters for processing and interpretation of seismic data. then the seismic sections near the borehole were calibrated. VSP data built a bridge which connected borehole drilling and borehole logging with surface seismic sections. A set of methods for borehole and surface combined exploration acquisition,processing and interpretation were obtained.Well Z51 was explored using borehole and surface combined 3D VSP. Acquisition parameters of surface and downhole were fully demonstrated, high S/N and resolution data was got, high S/N and resolution sections were obtained by processing unitedly, the block trap in borehole Z51 was further ascertained,two new block traps were found and characteristics of oil layer spread were decided.The sand body was recognized in borehole B139 and Z75,the areas of these sand bodies were 2.5km~2 and 1.5km~2. fault& lithologic trap about 3.28km2 in borehole B71 and B190 was predicted. Borehole and surface combined method could provide high precision data and facilitate petroleum exploration&development.