Technique for reconstructing 3D complex geologic body

Abstract

The invention relates to oil geophysical prospecting and 3D complex geologic body reconstruction technique: constructing an equipotential field-based initial curve; optimizing cell quality of triangular grid of the initial curve and building a topological relation between grid cells, then converting all the other known information into various fuzzy control restriction information according to the requirements of input model of a disperse smooth interpolation algorithm, additionally, converting all control points into restriction information of fuzzy control points, inputting all restriction information into a discrete smooth interpolator, and then calculating coupling relation of these restrictions and the initial grid curve model, thus eliminating the interactive point offsetting process for curve model construction of a multivalued body , making it convenient to implement the curve model construction of a complex multivalued body and interactive curve editing method is flexible and convenient.

Description

technical field [0001] The invention relates to petroleum geophysical prospecting technology, in particular to the construction of complex geological bodies, and is a technique for reconstructing three-dimensional complex geological bodies. Background technique [0002] In geophysical exploration, the surface construction of 3D seismic geological bodies is mainly to comprehensively utilize the data of geology, well logging, geophysical prospecting, field rock outcrops and other data in the exploration stage, and use certain geometric methods to construct the geometric distribution of oil reservoirs in 3D space. Based on boundary representation and grid representation, a certain grid is used to simulate the distribution of various attributes in 3D space, so as to provide a means of describing the reservoir as a whole in 3D space. [0003] With the deepening of oil and gas exploration, the requirements for geological modeling of complex structures are increasing. Popular geolo...

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Problems solved by technology

[0003] With the deepening of oil and gas exploration, the requirements for geological modeling of complex structures are increasing. Popular geological modeling software such as Earthvision and Gocad are basically equipped to deal with complex continuous and discontinuous multi-valued geological bodies (such as faults, folds, salt mound, lens, etc.), but the methods used have certain limitations

[0004] At the SEG annual meeting in recent years, the Earthvision construction surface of Dynamic Graphics, Inc (abbreviated as DGI) uses the three-dimensional minimum tension interpolation method based on the regular distance field to construct multi-valued objects. The problem of multi-valued body fracture, in addition, it is not possible to add other linear constraint information to constrain the model, only to use scattered control point information, and often need to add a certain amount of control points interactively, and adjust and optimize the model in a cyclic and iterative manner. The implementation process is cumbersome

In addition, due to the use of 3D gridding technology, if the grid sampling rate is high or the number of control points is known to be large, the amount of gridding calculation is very large. Of course, the method of coarse and fine grid splitting and data point thinning can be adopted, but for Subsequent interactive modification is not good

[0005] In the Gocad 3D reservoir description of TSurf in the United States, a discrete smooth interpolation is used to construct a complex model. This interpolation is a broad-spectrum interpolation. Its implementation idea is different from that of Erathvision software, and various constraints can be added for model constraints. And there is no need to embed the model into a regular three-dimensional uniform grid, only an initial solution is needed, which directly establishes the relationship between the constraint information and the model, and uses an iterative method to build the model. The disadvantage is that it is difficult to construct the initial surface , the topology information of the grid is relatively high, and the convergence is largely affected by the initial model. If the initial model is unreasonable, the algorithm will not be able to correctly approximate the known information, but only achieve local minimum convergence, and also Affecting the update of constraints requires that the topological changes of the grid and the changes of constraints must be completely accurate and fast

[0006] NORSAR in Sweden has also adopted the technology of fragmentation reconstruction and merging. In principle, this method can establish various complex models, especially if there are complex fractures. The division of data and space needs to be realized interactively

[0007] Some other automatic reconstruction methods, such as the method of directly triangulating in three-dimensional space, can only be realized when the data distribution is uniform. Once the data distribution is uneven or changes drastically, these methods often fail

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