Ancient landform recovery method for extrusion basin

Abstract

The invention relates to an ancient landform recovery method for an extruded basin, and belongs to the technical field of exploration and development. The method comprises the steps of obtaining seismic data of a target area, and determining a reference surface; performing tracking interpretation on an unconformity surface and a reference surface in a target stratum by using seismic data to obtain depth data of the top / bottom of the target stratum and a reverse fault of a target area; dividing the target layer into a plurality of fault blocks by taking the reverse fault as a boundary, and calculating thickness data of each fault block; selecting a section and determining the nail block to perform balanced section recovery to obtain the horizontal displacement of other fault blocks relative to the nail block; performing coordinate homing calculation on the thickness data of other fault blocks according to the horizontal displacement; and splicing and mapping the thickness data after coordinate homing to complete the restoration of the ancient landform. According to the method, coordinate homing calculation is carried out on the thickness data of each fault block according to the horizontal displacement, so that the influence of stratum stacking on stratum thickness calculation is eliminated, and the accuracy and precision of ancient landform recovery of the extrusion basin are greatly improved.

Description

technical field [0001] The invention relates to a palaeogeomorphological restoration method used in extrusion basins, and belongs to the technical field of exploration and development. Background technique [0002] Paleogeomorphology restoration refers to the restoration of the geomorphology of selected strata to before the deposition of the stratum by using seismic and logging data, which is an important link in basin analysis, sedimentary facies analysis and reservoir prediction. Commonly used paleogeomorphological restoration methods include: residual thickness method (residual thickness method), impression method, filling and leveling method, layer leveling method, stripping back method, etc. The basic principle of the residual thickness method is to select a stratum interface under the denuded surface as the base level, and use the residual thickness between the base level and the top surface of the weathering crust to indirectly reflect the paleogeomorphology. The imp...

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Problems solved by technology

[0003] In recent years, a variety of paleogeomorphological methods have been developed or improved to be suitable for different geological conditions. For example, the Chinese invention patent application document with the application publication number of CN 108267797 A discloses a paleogeomorphological method in a syngenetic normal fault development area inside a complex fault block. The restoration method of geomorphology, this method calculates the growth index of the syngenetic normal fault, and within the control range of the downthrown wall of the syngenetic normal fault, corrects the thickness of the downthrowing wall through the ratio of the thickness of the downthrowing wall to the growth index, and eliminates the need for paleogeomorphic restoration. The paleogeomorphology illusion caused by the thickening of the descending wall due to the gradual change of syngenetic normal fault activities makes the paleogeomorphology more reasonable. However, this method is only applicable to the area where syngenetic normal faults are developed. figure 1 The upper and lower wall strata overlap shown, cannot be corrected for thickness by growth index

[0004] The above syngenetic normal fault development areas are generally in extensional basins. However, for compressional basin areas, a large number of reverse faults are developed. When calculating the thickness of the formation, it is affected by the superimposition of the upper and lower walls. The thickness value error is large

For this reason, when solving the stratum thickness of a compressional basin, if the seismic data are processed first, and the faults and folds are restored, the workload will increase sharply; If the thickness of another plate is missing, the resulting data will be distorted, especially in areas with high and steep structures, where strata on the upper and lower walls of the fault are seriously superimposed. The lack of data on any plate may cover up important geological law information. At the same time, the upper and lower The relative position before the structural compression of the plate body has not been restored

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