Quantitative Calculation Method of Paleobathy for Lacustrine Sediments

Abstract

The present invention provides a method for quantitative calculation of paleo-depth for lacustrine deposition, the method for quantitative calculation of paleo-depth for lacustrine deposition includes: step 1, screening lakes similar to the research area; step 2, for the screened lakes, establishing Quantitative relationship between lake bottom sediment TOC and water depth; step 3, conduct mudstone TOC test for the research area, and count the stratum thickness of the target layer; step 4, establish the quantitative relationship between ancient water depth data and stratum thickness; and step 5, draw ancient Plane distribution of water depth. The paleo-depth quantitative calculation method for lacustrine sediments further improves the means of paleo-depth restoration, and provides new research ideas and technical means for the study of paleo-lake sedimentary evolution process and the prediction of multi-type lacustrine sand bodies.

Description

technical field [0001] The invention relates to the fields of theoretical research on sedimentary basins, technical application and geological exploration of oil and gas fields, in particular to a quantitative calculation method of paleowater depth for lacustrine deposition. Background technique [0002] Paleo-depth restoration is an important research work in oil and gas geological exploration, and it has important guiding significance for the study of basin sedimentary evolution process, sand body genetic type and distribution law. At present, the commonly used paleo-depth restoration methods mainly include qualitative and quantitative methods. In the early stage, qualitative paleogeomorphic restoration was the main method. Commonly used methods include residual stratigraphic method, sequence stratigraphic method, sedimentological method and gamma energy spectrum logging method, etc. Through the application of the above methods, it is possible to qualitatively restore the...

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Problems solved by technology

Another example is the superposition method of micro-paleontological categories. Since the distribution of paleontological fossils in the stratum is very uneven, in practice, there will often be no fossil points. The water depth data of such points can only be estimated based on data from adjacent points or other methods. The method is determined, resulting in unreliable paleo-depth restoration results

The shoreline trajectory method is mainly a seismic sedimentology method proposed for large-scale delta sedimentary areas. The calculation process of this method involves many factors such as decompaction, provenance supply rate, and late differential structural settlement. The calculation process is very complicated, and the theoretical Although rigorous in theory, the operability is poor, and the complexity of the delta deposition process itself has caused a lot of uncertainty to the actual restoration results.

[0004] For lacustrine deposits, the most commonly used method in oilfield exploration and production is still the stratum thickness method, that is, the current stratum thickness is used to approximate the ancient water depth in the geological history period, and the greater the thickness, the deeper the water body. Qualitatively reflect the shape of the lake basin

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