Oil and gas detection method of deep channel sand body based on decompaction

Abstract

The invention provides an oil and gas detection method of a deep river channel sand body based on a decompaction effect. The method includes steps: 1) editing and correcting a logging curve; 2) taking accurate interval transit times of a mudstone formation and a sandstone formation from shallow to deep, and respectively establishing normal compaction trend curves of mudstone and sandstone; 3) subtracting the compaction trend from a speed curve above a well to obtain a well speed curve after removing the compaction trend; 4) calculating parameters including the p-wave impedance, the s-wave impedance, and the Poisson's ratio etc. based on decompaction, further calculating inversely proportional Poisson's ratio parameters, and determining a threshold for containing coil and gas of a reservoir through crossed analysis; and 5) performing pre-stack simultaneous inversion based on a Zoeppritz equation, obtaining a plurality of elastic parameter bodies, further calculating inversely proportional Poisson's ratio parameter bodies, and predicting the oil-gas bearing property of the reservoir. According to the method, the influence of the formation compaction effect is eliminated so that the sensitivity of fluid parameters of the reservoir is improved; besides, the limitation of oil and gas detection of the deep river channel sand body by many oil and gas detection methods is broken through, the prediction precision of the reservoir fluid is improved, and oil and gas exploration risks are reduced.

Description

Technical field [0001] The invention relates to the field of comprehensive oil and gas exploration. It is a method for detecting oil and gas in deep channel sand bodies by obtaining an inverse Poisson's ratio parameter body through simultaneous pre-stack inversion of Zoeppritz equation based on decompaction. Background technique [0002] In the process of oil and gas reservoir exploration, the use of seismic data for oil and gas detection is playing an increasingly important role. From the use of post-stack seismic data to carry out seismic attributes, frequency-divided absorption attributes, and bright spot technology for oil and gas detection, to the use of pre-stack data to carry out AVO attribute analysis, Poisson impedance, and pre-stack inversion for oil and gas detection, these applications have been It is very extensive and has achieved certain results. However, for deep channel sand bodies, as the buried depth increases, the degree of compaction of sand and mudstone for...

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Problems solved by technology

[0006] For deep channel sand bodies, due to the large burial depth, the sandstone and mudstone in the formation are subject to strong compaction, so that the porosity of the sandstone and mudstone decreases rapidly, and the velocity difference between the two also gradually decreases, and further As a result, under the background of large burial depth and strong compaction, the existing petrophysical parameters cannot effectively distinguish sand and mudstone, so that it is impossible to effectively solve the problem of channel sand oil and gas detection, which greatly affects the exploration deployment in the study area

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