The application of phase-controlled inversion in prediction of deeply buried marine reef-bank reservoirs in the central Tarim Basin

Abstract The deeply buried marine carbonate reef-bank reservoirs deposited in the central Tarim Basin are characterized by serious heterogeneity and relatively thinner thickness, obviously controlled by sedimentary facies, which has resulted in many difficulties in differentiating these reservoirs by conventional inversion methods. So, this paper presents a phase-controlled inversion. Firstly, seismic facies models are constructed by comparing the differences of the seismic response characteristics of the reef-bank reservoirs. In this process, macro-seismic phase division is similar to sedimentary facies in operation, but the difference of seismic reflection features is highlighted in the division of the small-scale seismic phases. According to the plane and spatial distribution of different seismic facies, we can count seismic and drilling sample data corresponding to different seismic facies. On the basis of the phase-controlled model, geostatistical inversion can then be applied to precisely predict the spatial distribution of the carbonate fracture-vug reservoirs. What differs from the conventional seismic inversion method is that this phase-controlled, geostatistical inversion has used the cluster analysis of seismic and well data involved in inversion to obtain a more reliable variogram of the impedance and lithology. This procedure has greatly improved the accuracy and geological rationality of the inversion.