Karst ancient landform restoration method with hydrothermal cause siliceous rock as isochronous datum plane

Abstract

The invention discloses a karst ancient landform restoration method with hydrothermal cause siliceous rock as an isochronous datum plane. The karst ancient landform restoration method comprises the following steps: acquiring rock core, slice and logging information; stratigraphic division and comparison are carried out, and the hydrothermal cause siliceous rock bottom boundary is determined to serve as an isochronous reference plane; finely explaining an isochronous reference surface and a target layer erosion surface; calculating the residual stratum thickness between the isochronous reference surface and the target stratum erosion surface; and obtaining a karst ancient landform map according to the residual stratum thickness. According to the method, the principles that the reference surface is isochronous and close to the erosion surface and the earthquake response is clear and easy to track are fully considered, and the recovery precision of the ancient karst landform is greatly improved.

Description

technical field [0001] The invention relates to the technical field of karst paleo-geomorphology restoration in the petroleum industry, in particular to a method for restoring karst paleo-geomorphology with the hydrothermal siliceous rock as the isochronous datum level, specifically taking the bottom boundary of the hydrothermal siliceous rock as the isochrone Datum. Background technique [0002] In recent years, the restoration of karst paleo-geomorphology has become a hot spot in the study of carbonate reservoirs, but it is usually very difficult to restore karst paleo-geomorphology, which has always been a worldwide problem. Exploration practice shows that the karst reservoir development area is closely related to karst paleogeomorphology. It is generally believed that karst mounds and karst slopes are the areas where karst reservoirs are most developed, while karst highlands and karst valleys are areas where karst reservoirs are relatively undeveloped. Therefore, accur...

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Problems solved by technology

[0003] In the early stage, the inventor carried out the restoration of the karst paleogeomorphology at the top of the Dengying Formation in the GS area of ​​the Sichuan Basin by using the residual thickness method and the impression method, but there are various degrees of defects and the restoration accuracy is low

By selecting the bottom of the Dengying Formation, the bottom of the third Dengying Formation and the bottom of the fourth Dengying Formation as the isochronous datum, the defect of using the residual thickness method to restore karst paleogeomorphology is that there were multiple stages of tectonic activities during the deposition of the Dengying Formation, and the strata were denuded. unequal time, and the seismic events at the bottom of the Deng 3 Member and Deng 4 Member vary greatly, making it difficult to track accurately

By selecting the top boundary of the Longwangmiao Formation and the top boundary of the Canglangpu Formation as the isochronous datum, the defect of using the impression method to recover karst paleogeomorphology is that the deposition time between the selected datum level and the erosion surface of the top boundary of the Dengying Formation is relatively long, and Due to the large variation of sedimentary facies in the Longwangmiao Formation, the seismic event at its top boundary varies greatly, making it difficult to track accurately

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