A frequency domain co simulation based phased seismic inversion method for areas with few wells is proposed to address the problem of insufficient well data and difficulty in constructing an initial inversion model in the Indian fan offshore basin. The elastic parameter distribution characteristics of different intervals are statistically analyzed using well logging data from the research area and adjacent exploration areas. A quasi bundle discrete model is constructed and combined with the seismic 90° phase shift attribute to create a virtual well curve. Using virtual well curves as hard data and seismic facies interpretation results as soft data, a new frequency domain co simulation method is used to construct a phased initial model. Based on the phase controlled initial model, an objective function is established to predict the biogenic reef reservoir through pre stack elastic impedance inversion. The actual application results in the work area show that the inversion initial model constructed based on frequency domain co-simulation method contains richer information. The inversion results based on this initial model successfully predict the dominant reservoirs of the reef, proving the effectiveness and reliability of this method. Compared with traditional deterministic inversion methods, this inversion method has more advantages in reservoir prediction in areas with few wells.