Foreland basin alluvial fan fine description and prediction method

Abstract

The present invention provides a foreland basin alluvial fan fine description and prediction method. The method comprises a step of establishing a foreland basin alluvial fan geological model, a step of establishing the stratigraphic framework of an alluvial fan, a step of carrying out seismic facies and attribute inversion to delineate the plane distribution range of an alluvial fan, a step of carrying out three-dimensional electrical inversion to divide the phase band boundary of the alluvial fan of each period, carry out the fine identification of internal lithology and lithofacies, and determine the spatial distribution characteristics of the lithology and lithofacies, and a step of applying OpenDtect software to analyze the alluvial fan vertical evolution and establishing the deposition model of a study area alluvial fan. The method provided by the invention is mainly based on the sedimentology theory and the geological model foundation established by alluvial fan exposure investigation, logging, seismic, electrical method and other materials are fully utilized, the means of logging geological interpretation, seismic sequence analysis, seismic facies interpretation, attribute analysis and electrical method interpretation are integrated, and each phase band of the alluvial fan and the internal lithology and lithofacies spatial distribution characteristic are effectively identified.

Description

technical field [0001] The invention relates to a fine depiction and prediction method of an alluvial fan in a foreland basin, belonging to the technical field of oil exploitation and geological exploration. Background technique [0002] Because alluvial fans are rich in coarse-grained sediments such as sand and gravel, they can often form reservoirs. Alluvial fan reservoirs account for about 6.0% of clastic rock reservoirs in my country, such as the glutenite reservoirs of the Karamay Formation in the Hongshanzui Oilfield in the northwestern margin of the Junggar Basin , Triassic glutenite reservoir in Karamay Oilfield, alluvial fan reservoir in the northern steep slope of Jiyang Depression, Zaoyuan alluvial fan reservoir in Huanghua Depression, Shanle Paleogene gas reservoir in Tuha Basin, etc. At the same time, large-area alluvial fans are easy to form in foreland basins, in which the thickness of coarse-grained rocks varies greatly, the lateral distribution is wide, and d...

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Problems solved by technology

[0008] However, the background of foreland basins is usually that the mountains are uplifted quickly, the piedmont space is large, and alluvial fans are developed in large-scale fan groups with a wide distribution area, so it is difficult to predict; secondly, there are often high mountains in front of foreland basins, and earthquake The data acquisition and processing are difficult and the quality is poor, which cannot meet the quality requirements of conventional seismic inversion technology for seismic data

These two points greatly reduce the accuracy of alluvial fan prediction by seismic methods

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