Forecasting and evaluating technologies of three-dimensional earthquake optimum time window river course sand body storage layer

Abstract

The invention discloses a prediction and evaluation technology of 3D seismic optimum time window river channel sand body reservoirs, belongs to the technical field of the prediction and evaluation of the 3D seismic reservoirs, and aims at solving technical problem that the river channel predictive resolution of the traditional methods is not enough. The technical proposal is as follows: the 3D visualization scanning is performed on each reservoir at the interval of 1-2ms, the optimum time window is determined according to the scope shown by the target river channel, the corresponding subfield is cut out, clairvoyance and scanning are carried out on the time window properties, such as root-mean-square amplitude, wave impedance and the like, auto-tracing is performed, top surface and bottom surface are picked up, a time isopach map is calculated and converted into a sand body isopach map, a top surface structure diagram is formed by time-depth conversion, and the reservoir physical properties are evaluated by curve reconstruction, thus realizing the prediction and evaluation of the plane morphology, longitudinal thickness and the reservoir physical properties of the river channel sand body. The method adopts the optimum time window to effectively inhibit interference, is applicable to various data volumes, and can effectively predict and evaluate a thin river channel sand body with the thickness far less than 1 / 4 of a wavelength under the condition of frequent interbedding of sand and mudstone, the thin river channel sand body comprises the river channel sand body which is not corresponding to wave crest or wave trough, and the method has good application effect in petroleum exploration and development.

Description

technical field [0001] A 3D seismic reservoir prediction and evaluation technology, especially capable of predicting and evaluating the spatial distribution, reservoir characteristics, oil and gas, production capacity, etc. Background technique [0002] There are many existing 3D seismic reservoir prediction technologies for channel sand bodies, including recursive inversion, model inversion, multi-parameter inversion, etc., which are mainly constrained by known geological laws, drilling and logging data, and geological models. Imaging of the spatial structure and physical properties of underground strata, such as well-constrained wave impedance inversion, model-controlled wave impedance inversion, stochastic analog wave impedance inversion, curve reconstruction wave impedance inversion, colored inversion, frequency division inversion, etc. Impedance inversion, and various 3D seismic attribute inversions. One type of 3D seismic inversion is a method based on geophysical the...

AI Technical Summary

Problems solved by technology

The three-dimensional visualization interpretation is mainly fast scanning, perspective, and carving of troughs or peaks. Basically, the energy weakening point, waveform change point and polarity reversal point on the seismic section are used as the boundary of the sand body. Its advantages are fast and intuitive, and its disadvantage is the seed Point automatic tracking is easy to cross layers, and the accuracy of thickness prediction is low

[0004] Channel sand bodies change frequently in three-dimensional space, and often appear as a series of thin channel sand bodies and mudstones frequently interbedded. Therefore, for channel sand body prediction, model inversion, random inversion, attribute inversion, and multi-attribute inversion have their own advantages and disadvantages. Advantages and disadvantages, the common weakness is that it is not ideal for thin interbedded sand and mudstone

[0005] In the method based on geophysical theory, model inversion is difficult to establish an effective model; random inversion is difficult to determine the boundary conditions such as the direction of constrained sand bodies, and well-controlled wave impedance inversion is limited by seismic resolution, which cannot effectively reflect thickness less than 3D seismic Single sand body with high resolution;

[0006] In the method based on geostatistics, the automatic tracking of seed points is easy to channel, and the reflected thickness is usually greater than the actual thickness; the plane attribute cannot reflect the change of sand body thickness; it is difficult to control the reasonable interval for daughter body inversion, and the information is incomplete if the interval is too small. The displayed sand body distribution characteristics are unstable, if the interval is too large, there will be more interference information other than the target sand body, and adjacent sand bodies will overlap; multi-attribute inversion is still not enough to solve the influence of single sand body thickness and adjacent layers The contradiction between large and insufficient seismic resolution

[0007] Purpose of the invention Aiming at the existing reservoir prediction and evaluation technology, the plane of the channel sand body is complex and changeable, the thickness of a single layer is less than 1 / 4 wavelength, and the longitudinal overlap is frequent, and the seismic resolution is difficult to meet the needs of prediction and evaluation. Establish an effective 3D seismic channel sand body reservoir prediction and evaluation technology to predict and evaluate thin sand bodies smaller than the vertical resolution of 3D seismic

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