Application of seismic rock physical modeling technology in tight sandstone gas of Dibei Ahe Formation
The low porosity and low permeability sandstone of Jurassic Ahe formation in the Dibei area of Kuqa depression in Tarim Basin is the main reservoir of the Dibei gas field.The petroleum geological conditions are superior,oil and gas have been observed in many wells.Due to fractures in the sandstone of Ahe formation in this area,the complex pore structure of the reservoir,no singular relationship between porosity and velocities,and the conventional Xu-White modeling with a single sand-stone pore structure generally poor shear wave data.This article proposes a method based on the Xu-White modeling of sand-stone with variable sand pore structure in response to this issue.Firstly,this paper conducts a forward simulation of the sand-stone pore aspect ratio based on the differential effective medium model and calculates the sandstone aspect ratio curve using the fitting relationship between the simulation results and porosity.Then,based on the Xu-White modeling of sandstone with vari-able sand pore structure,elastic curves of Ahe formation is modeled,compared with the Xu-White modeling with a single sand-stone pore structure,it has a higher degree of agreement with measured curves.Finally,based on the modeled logging curves and rock physics interpretation plates,the tight gas reservoir of the Ahe formation was identified.After modeling,the elastic response characteristics of the gas reservoir are more pronounced,manifested as Poisson's ratio is less than 0.18,and the bulk modulus value is generally less than 3.0×104MPa.Seismic rock physics interpretation templates are established in this area to investigate the quantitative changes in elastic parameters caused by quantitative changes in fluid saturation under different"dry"rock matrices.This basically frames the elastic response window of gas reservoir,providing a reliable theoretical basis for res-ervoir and fluid prediction for following seismic reservoir inversion.
Dibei slopetight gaspore structure modelingseismic rock physicalgas reservoir identification
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