Foreland basin deep buried and compressed type complex gypsum-salt rock identification and distribution prediction method

Abstract

The invention provides a foreland basin deep buried and compressed type complex gypsum-salt rock identification and distribution prediction method. The method comprises the following steps that: according to lithological vertical change in outcrop data, drilling data and logging data, a lithological sequence caused by sedimentary environment change is reserved, and a gypsum-salt rock deformation and overlying sequence caused by tectonic compression and fault repetition is eliminated, and an original lithologic sequence is established, and an ancient landform model of a research area is recovered through the original lithologic sequence, and a current tectonic model is recovered; and three-dimensional gravity, magnetic, electric and seismic joint inversion is carried out, and lithological and lithofacies interpretation of gypsum-salt rock at the surrounding region of a borehole is carried out through electrical methods, seismic facies and density anomaly and by means of the original lithologic sequence and the current tectonic model, and therefore, a lithological sequence plane distribution rule can be determined. According to the method provided by the invention, based on foreland basin gypsum-salt rock deformation characteristics which are obtained through geologic modeling, and geophysical methods such as three-dimensional gravity, magnetic, electric and seismic methods are adopted to perform joint inversion, and therefore, the distribution characteristics of post-deformation gypsum-salt rock can be accurately determined.

Description

technical field [0001] The invention relates to a method for identifying and predicting the distribution of deep-buried and extruded complex gypsum-salt rock layers in foreland basins, and belongs to the technical field of oil exploitation and geological exploration. Background technique [0002] Gypsum-salt rock is a chemically-genetic sedimentary rock that is formed after the evaporation of water and the gradual concentration of salt, also known as "evaporite". In my country's sedimentary basins, a large number of gypsum-salt rocks were distributed in the Cambrian, Ordovician, Triassic, Cretaceous and Paleogene periods. Used in chemical industry, medicine, agriculture, glass, explosives and other fields, it is a scarce mineral resource, which is of great significance to national economic construction and resource security. In addition, gypsum-salt rocks are generally non-permeable layers, and many large and super-large oil and gas fields often use extremely thick gypsum-sa...

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Problems solved by technology

Therefore, this superposition can lead to multiple gypsum-salt rock formations spaced apart from each other vertically, which cannot be accurately predicted by the above-mentioned existing geophysical well detection methods.

Secondly, the signal-to-noise ratio of piedmont seismic data is low, the seismic velocity spectrum data relied on is distorted, and the accuracy of electrical detection is low, there is no good concept of layers, and it is difficult to reflect the accurate changes of deep lithology

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