Method and device used for hydrocarbon quantitative prediction and based on unconsolidated sandstone model

Abstract

The invention provides a method and a device used for hydrocarbon quantitative prediction and based on an unconsolidated sandstone model. The method comprises the steps of obtaining background information of reservoir rock, according to the background information of the reservoir rock, calculating a dried rock modulus of the constant-cement unconsolidated sandstone model, calculating vertical and horizontal wave speeds of constant-cement unconsolidated sandstone when water is saturated, arranging a porosity degree and saturation level distribution range according to the constant-cement unconsolidated sandstone model, calculating formulas that a shear modulus corresponding to each porosity degree and saturation level and the horizontal wave speed are divided by density, building a rock physical template where a parameter that the shear modulus is divided by the density and a parameter that the horizontal wave speed is divided by the density are jointed, carrying out pre-stack synchronous inversion on earthquake pre-stack trace gathering, enabling the obtained shear modulus and the horizontal wave speed during the inversion to be divided by the density and projected to the rock physical template where the parameter that the shear modulus is divided by the density and the parameter that the horizontal wave speed is divided by the density are jointed, calculating the porosity degree and the saturation level of a target reservoir by a template mapping method, and judging an oil-gas distribution condition of the target reservoir. The method and the device used for the hydrocarbon quantitative prediction and based on the unconsolidated sandstone model improve prediction accuracy of the effective reservoir.

Description

technical field [0001] The invention relates to the field of seismic rock physics model and seismic pre-stack inversion in geophysical prospecting, in particular to a method and device for quantitatively predicting hydrocarbons based on a loose sandstone model. Background technique [0002] The source rocks in the Sanhu area of ​​the Qaidam Basin are mainly Quaternary lacustrine dark mudstone, and the reservoirs are fine sandstone, siltstone, and argillaceous siltstone of shore-shallow lacustrine facies, with oolitic sandstone locally developed; Mainly mudstone, sandy mudstone and sandy mudstone. Due to the low degree of compaction, the particles are mostly in point contact, and the primary pores are developed. Sandy rocks generally have high porosity (average porosity 20-40%) and high permeability (average permeability 10×10 -3 ~1000×10 -3 μm 2 ), so the frequent occurrence of lacustrine sand beds constitutes an ideal reservoir for Quaternary biogas. Years of research ...

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Problems solved by technology

However, because the P-wave velocity of highly porous unconsolidated sandstone is insensitive and non-monotonic to the change of gas saturation,

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