Application of pre stack inversion technology in shallow gas reservoir identification of Huangjue oilfield in Gaoyou sag

The shallow gas reservoir of Huangjue oilfield in Gaoyou sag has complex structure, so conventional elastic parameters cannot distinguish lithology and fluid completely. In order to form a shallow gas reservoir identification mark according to the geological characteristics of Huangjue oilfield, through the comprehensive analysis of seismic, geological and logging data, especially the petrophysical analysis of the target interval of key wells, the idea of identifying shallow gas reservoir by fluid identification factor, which is a sensitive factor defined by combining P-S wave velocity and density, is put forward. Comparing the inversion result of fluid identification factor with that of conventional elastic parameter, it is found that the inversion of fluid identification factor can effectively identify the gas bearing property of the target interval. Compared with singly elastic parameter inversion results, the result has higher accuracy and reliability, which points out the direction for shallow gas reservoir exploration and favorable area prediction in Huangjue oilfield.