Application of seismic waveform indicator inversion for low-permeability reservoirs prediction in Zhujiang Formation of the EA Oilfield

The prediction of low-permeability reservoir is always a tough issue in exploration and development. The Zhujiang Formation of the EA Oilfield in the Yangjiang Depression is a typical low-permeability reservoir. The reservoir is generally characteristic of rapid lateral change and poor continuity of sand body. The single sand body features low porosity and low permeability. The accuracy of traditional seismic inversion for this type of reservoir is low. To obtain high-precision inversion results, the method of seismic waveform indicator inversion was adopted, and the lateral change of seismic waveform instead of the variation function was used. First, on the basis of using the permeability curve as a sensitive curve, the overmolding porosity and overmolding permeability of the sample were obtained by overmolding correction and fitting. Secondly, according to the difference of lithology and filler, three permeability models were established to obtain permeability curves. Finally, the permeability curve was used to invert the waveform indicator to obtain the inversion result and sand body thickness. Results show that the seismic waveform indicator inversion could improve the lateral and vertical prediction accuracy of the reservoir, and it could be successfully predict the sand body boundary and sand body thickness. The forecast results provided a guidance for additional oil and gas exploration and development.