US 5,844,564 AGranted

Method for generating a 3D-grid pattern matching the geometry of a body in order to achieve a model representative of this body

AssigneeInstitute Francais du Petrole

InventorsChakib Bennis, William Sassi

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Abstract

The invention is a method applicable to a geologic structure, such as an oil bearing reservoir, defined from available data acquired either through measurements or through analyses and interpretations of seismic data or loggings performed in wells. The invention comprises previous modeling of the boundaries (zone edges, discontinuities or faults for example) by of triangulated surfaces enveloping as far as possible these boundaries and splitting up of the zone studied into blocks having at most six faces, whose faces correspond to discontinuities or main faults of the zone previously triangulated. Each block is thereafter subdivided into a set of elementary cells necessary for modeling the zone by finite elements or differences, by performing a gridding of each of the faces of the block by interpolation from the edges thereof so as to obtain a grid, followed by populating each block with nodes in the thickness thereof, by interpolation from the nodes of the various grids formed on the various faces, these operations being accompanied by particular homogenization procedures in order to readjust the size of the cells within each block according to predetermined rules. The gridded blocks are thereafter reassembled.

Claims18

Dependent claims

A method for generating a 3D grid pattern in a volume of a structure of known and a priori imposed geometry defined from data acquired from seismic data or loggings performed in wells through the structure, in order to provide a model representative of the structure, including:

modelling boundaries of the volume by triangulated surfaces, enveloping as far as possible boundaries;
splitting up the volume into blocks having at most six faces, the faces corresponding to discontinuities or main faults of the volume;
generating an intermediate grid with quadrangular meshes between edges of each of the faces by interpolation between determined distributions of points sampled on the edges;
projecting nodes of the quadrangular meshes in a predetermined direction onto the triangulated surfaces, so as to generate face grids;
rearranging positions of the nodes of the face grids by a first relaxation of positions of the nodes according to a predetermined criteria;
populating each block with internal nodes positioned by interpolation between the nodes of the face grids so as to obtain an intermediate 3D grid with a determined distribution of the internal nodes in a volume of each block;
and
rearranging positions of the internal nodes by a second relaxation of the positions thereof according to a determined criteria.

5 more elements

Dependencies are inferred from the claim text.