Shale gas reservoir free gas content earthquake predicating method and system thereof

Abstract

The invention discloses a shale reservoir free gas content earthquake predicating method and a system thereof. The method comprises the steps of respectively acquiring work area elastic parameters andtime domain well logging data based on a work area pre-stack seismic data volume and depth domain well logging data; establishing a rock physical model based on the work area elastic parameters, andobtaining porosity and gas saturation; based on seismic data and ground temperature gradient, respectively acquiring a stratum pressure and a stratum temperature, and furthermore obtaining a volume coefficient; and based on the porosity, the gas saturation, the volume coefficient and the stratum pressure, establishing a calculation model of the free gas content, thereby obtaining the free gas content, wherein the work area elastic parameters comprise longitudinal wave impedance, transverse wave impedance and density. According to the shale reservoir free gas content earthquake predicating method and the system, through restraining the factors such as the stratum temperature, the stratum pressure, porosity and gas saturation, high-precision predication for free gas content of the shale reservoir is realized.

Description

technical field [0001] The invention relates to the field of oil and gas geophysical exploration, in particular to a seismic prediction method and system for the gas content of free gas in shale reservoirs. Background technique [0002] Shale gas is a natural gas energy that can be exploited in shale formations. It has the advantages of long mining life and long production cycle. It is a clean and efficient energy resource. Free shale gas exists in the pores or fractures of shale, and its quantity depends on the pore and fracture space in shale. The gas content of shale is of great significance to the evaluation of shale reservoirs and the selection of favorable areas. Existing methods for predicting gas content include on-site desorption method, logging interpretation method, TOC fitting method and so on. [0003] The inventors have found that the existing method has problems such as small estimates and large errors due to ignoring other influencing factors, resulting in l...

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Problems solved by technology

[0003] The inventors have found that the existing method has problems such as small estimates and large errors due to ignoring other influencing factors, resulting in large differences in the obtained gas content values, which is not helpful for the prediction of resource reserves and the identification of favorable areas by using gas content. preference brings difficulties

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