A method and device for determining paleogeomorphology of sedimentary strata

Abstract

The invention provides a method and device for determining a sedimentary stratum ancient landform. The method comprises the steps that objective horizon obtained in advance is divided according to the third-order sequence division mode in the sequence stratigraphy theory, and a sequence stratigraphic framework of the objective horizon is built to determine the studying sequence; the horizon, in accordance with the preset requirements, in the studying sequence is selected as restoring horizon; the thickness of the restoring horizon is obtained according to the top boundary and the bottom boundary of the restoring horizon; decompaction treatment is performed on the thickness of the restoring horizon to determine the original sedimentary thickness; the sedimentary stratum ancient landform is determined according to the mirror-image relationship between the original sedimentary thickness and the ancient landform. According to the method and device for determining the sedimentary stratum ancient landform, the condition that a denudation phenomenon may exist in the objective horizon is considered, the sequence stratigraphic division is performed on the objective horizon, a selection method of the restoring horizon is discussed under the constraint of the sequence stratigraphy theory to obtain the accurate stratum thickness used for ancient landform restoring, and therefore the accuracy of ancient landform restoring is improved.

Description

technical field [0001] The invention relates to the technical field of paleogeomorphology restoration, in particular to a method and device for determining paleogeomorphology of sedimentary strata. Background technique [0002] Restoring the shape of paleogeomorphology, exploring the control of paleogeomorphology on sedimentary environment, sedimentary facies, and oil and gas reservoirs, and finding favorable zones for the development of oil and gas reservoirs can provide certain guidance for oil and gas exploration and development in oil and gas bearing basins and reference value. Moreover, paleogeomorphology has a certain influence on the enrichment of various types of mineral resources such as coal and uranium. Therefore, paleogeomorphology has become the focus of current research, and the research on paleogeomorphology mainly focuses on the restoration methods of paleogeomorphology. Accurately obtaining the shape of paleogeomorphology is of great significance for effect...

AI Technical Summary

Problems solved by technology

[0003] The existing technical scheme is based on seismic interpretation and compaction restoration to draw paleogeomorphology. The basic principle is as follows: assuming that the sediments fill up the basin during the deposition process in a certain geological period, the original sedimentary thickness and The paleogeomorphology is a mirror image relationship, that is, the paleogeomorphology is lower in places with large sediment thickness, and the paleogeomorphology is higher in places with thin sediment thickness. In this way, the paleogeomorphology is obtained. This method is to study the target horizon as the recovery horizon. The difference between the depth of the top interface and the bottom interface of the target layer can be obtained, so as to determine the original sedimentary thickness of the paleogeomorphology, but in fact, the geological horizon (that is, the target horizon) used to restore the paleogeomorphology is not necessarily continuous deposition , the exposure and denudation of some areas or even the whole area may have occurred during the deposition process, part of the thickness of the stratum was weathered and denuded, and the obtained original depositional thickness was inaccurate, which made the basic assumption untenable. Therefore, the original There is an error in the deposition thickness

[0004] From the above, it can be seen that the existing technical scheme regards the target horizon as the restoration horizon of the research area, without considering the denudation phenomenon in some areas or even the whole area during the deposition process, that is, for the purpose of restoring paleogeomorphology The layers are not necessarily deposited continuously, so the original sedimentary thickness cannot be accurately determined using the existing technology, and thus the original sedimentary paleogeomorphology cannot be accurately obtained

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