Abstract:

Shahejie Formation reservoir in Qikou 18-1 Block belongs to fan delta facies, with rapidly changed sand body, and the sparse well data in the block is not enough for the reservoir study of high accuracy. According to this complicated geological feature and limited well data, high quality reservoir sandstone distribution of the block is predicted with 3D seismic data by the method of seismic attributes analysis and seismic inversion controlled with well logs.  On the basis of lithologic calibration with well data, optimum selecting seismic attributes extracted from 3D seismic data, especially RMS, is able to discriminate the thick sandstone from the mudstone, and as a result, the scope of fan delta, which is the favorable sedimentary facies of the block, can be determined with the sandstone distribution. Afterwards, high quality reservoir sandstones within fan delta and its internal architecture can be determined by seismic inversion controlled with well logs, which provides the geological  evidence to make or to adjust the development plan of the block. Practically, it is proved that this set of reservoir prediction technology is comparatively fit for determination of favorable target in offshore oilfield with sparse well net and is useful for risk reduction in development.

Key words: seismic attributes, seismic inversion controlled with well log, sparse well net, reservoir prediction