Gas reservoir identification method and device

Abstract

The invention provides a gas reservoir identification method and device. The method comprises the following steps: generating near-offset superposition data and far-offset superposition data according to seismic data of a target work area and an offset range capable of reflecting gas well characteristics; generating an instantaneous amplitude difference value between the near-offset superposition data and the far-offset superposition data of the gas reservoir of the target work area according to the near-offset superposition data and the far-offset superposition data; generating main frequency parameters of a water well and a gas well according to the far offset superposition data, and obtaining instantaneous frequency parameters of the far offset superposition data; and identifying the gas reservoir of the target work area according to the amplitude difference, the dominant frequency parameter and the instantaneous frequency parameter. According to the gas reservoir identification method provided by the invention, the pre-stack AVO amplitude difference information and the seismic frequency information are fully utilized, the plane distribution of the gas reservoir is effectively predicted, the multiplicity of solutions of gas reservoir identification is reduced, and the precision of gas reservoir identification is improved.

Description

Technical field[0001]The present invention relates to the field of petroleum exploration, especially in the field of hydrocarbon detection in the field of geophysical exploration, and more particularly to a gas layer recognition method and apparatus.Background technique[0002]In recent years, the new proven reserves of natural gas have increased, how to improve natural gas exploration and development benefits, and ensure that natural gas production is steadily growth is an extremely complex problem. The global physical gas test is a key content that promotes efficient exploration and development of natural gas, and is one of the most important difficulties. Typical gas layers have features such as low speed, low density, low-rod stroning ratio.[0003]Currently used gas layer detection methods include AVO technology, absorption attenuation technology and seismic inversion techniques. After the introduction of Bortfeld in the 1960s, AVO technology has been promoted by many scholars, but...

AI Technical Summary

Problems solved by technology

The AVO technology was proposed by Bortfeld in the 1960s, and has been popularized and applied by many scholars. However, it was later found that the AVO technology mainly analyzes the characteristics of the variation of the amplitude with the offset (that is, the amplitude information). Due to the low velocity, low density, and Low Poisson's ratio and other characteristics, and there are multiple solutions caused by small lithological differences or different fluids; the absorption and attenuation technology is mainly based on frequency information for gas layer detection. At present, many mature technologies have been derived, but their prediction resolution is low , due to the influence of lithology, there are strong multi-solutions; seismic inversion technology, especially pre-stack seismic inversion technology, has been developed for many years and has gradually matured in gas layer detection and has been popularized and applied. The requirements for well data are relatively high, and most blocks cannot meet the requirements for pre-stack inversion gas layer detection

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