Forecasting method for brittleness of compact oil and gas reservoir and device

Abstract

The invention discloses a forecasting method for brittleness of a compact oil and gas reservoir and a device. The method comprises the following steps of: acquiring a model relation on the basis of an acquired well logging curve and utilizing the model relation to establish a shear wave velocity forecasting model; forecasting and acquiring a shear wave velocity curve on the basis of the shear wave velocity forecasting model; calculating an elastic parameter curve according to the shear wave velocity curve, a density curve and a longitudinal wave velocity curve; acquiring a quartz content data on the basis of a quartz content well logging curve and a post-stacked seismic data; acquiring a brittleness index on the basis of the quartz content data; acquiring a time depth curve and a seismic wavelet on the basis of pre-stacked seismic data, the longitudinal wave velocity curve and the density curve; and establishing an initial model on the basis of the time depth curve, the density curve and the elastic parameter curve, and then acquiring a compound angle set of different angles and establishing an inversion equation through the compound angle set and a pre-stacked angle set, thereby inversing and acquiring the data of Young modulus; acquiring the data of the brittleness index on the basis of the quartz content data and the data of Young modulus.

Description

technical field [0001] The invention relates to the technical field of petroleum geophysical exploration, in particular to a method and device for predicting the brittleness of tight oil and gas reservoirs. Background technique [0002] In recent years, the exploration and development of unconventional oil and gas resources has attracted the attention of experts at home and abroad. Tight oil and gas reservoirs, as an important part of them, have become hot spots and difficulties in oil and gas exploration. Tight oil and gas refers to tight sandstones with extremely low permeability, For oil and gas in reservoirs such as tight carbonate rocks, the production of a single well fails to form an industrial oil flow, but it can form an industrial oil flow under certain exploitation measures. This type of reservoir has the characteristics of low permeability, complex pore structure, complex mineral composition, and obvious brittle characteristics. Among them, brittleness is an imp...

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Problems solved by technology

[0005] Although the above two methods have played an important role in tight oil and gas reservoirs, they are obviously insufficient for the brittleness prediction of fine tight reservoirs, mainly in the following aspects: failure to comprehensively consider the mechanical properties and mineral components of rocks , the correct relationship between the brittleness index and the elastic parameters of the reservoir cannot be established, and the rock characteristics cannot be quantitatively described; the brittleness index calculated by the elastic parameters obtained by simple pre-stack inversion lacks the guidance of the quantitative relationship, which makes the inversion accuracy greatly For special tight reservoirs, there are weak research foundations in seismic petrophysics, reservoir geophysical characteristics, reflection patterns and AVO characteristics, which cannot effectively guide the exploration of tight oil and gas

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