초록 ▼

The method uses the image obtained by accumulating continuity curves representative of seismic horizons so as to determine the geological strata constituting the seismic section, such as they were deposited and not such as they are observed today. To do this, the method defines a transformation of t

The method uses the image obtained by accumulating continuity curves representative of seismic horizons so as to determine the geological strata constituting the seismic section, such as they were deposited and not such as they are observed today. To do this, the method defines a transformation of the vertical scale of the seismic section, scale measured in seismic times, into a geological vertical scale measured in geological times. This transformation is based on an equalization of histograms. Starting from equalized histograms, the method makes it possible to determine equalized seismic sections which are used to determine the rates of sedimentation which governed the depositions of geological strata. In particular, it highlights geological hiatuses, that is to say erosions and gaps.

대표청구항 ▼

1. Method of chrono-stratigraphic interpretation of a seismic image section S which comprises a horizontal dimension or width and a vertical dimension or height in the direction of the subsoil and which consists of columns of pixels, consisting in:defining a matrix M identical in size to the image s

1. Method of chrono-stratigraphic interpretation of a seismic image section S which comprises a horizontal dimension or width and a vertical dimension or height in the direction of the subsoil and which consists of columns of pixels, consisting in:defining a matrix M identical in size to the image section S and consisting of elements each of which is associated with a pixel of the image section S and is initially assigned a zero value,for each pixel i of the image section S, calculating a continuity curve Ci passing through the said pixel and transverse to the vertical dimension of the image section S,incrementing an element of the matrix M by one unit each time the pixel with which it is associated in the image section S is crossed by a curve Ci,and characterized in that it furthermore consists in:constructing, for each column c of the matrix M, a histogram Hc consisting of a number of classes which is equal to the number of elements of the said column c, each class corresponding to one of the elements of the column c and containing a number of samples which is equal to the value aggregated in the relevant element of the matrix M, which value is equal to the number of curves passing through the pixel associated with the said element, the total number of samples distributed in the histogram constructed for each column being equal to the total number of pixels in the image section S,equalizing each histogram Hc so as to produce an equalized histogram Hc′,defining an empty image section S′, whose width in pixels is identical to the width in pixels of the image section S and whose height in pixels is equal to the number of classes of the histograms Hc′,assigning the distribution defined by the equalized histogram Hc′ to each column c′ of the image section S′ by allocating each pixel of the column c′ the cardinality of the content of the associated class of Hc′,delimiting in the image section S′ the groups of contiguous pixels containing samples and labelling each of the said groups,allocating each pixel of the image section S the label given to the pixel group to which it was assigned in the image section S′ and displaying the labelled image section S. 2. Method according to claim 1, characterized in that the calculation of the continuity curve Ci transverse to the vertical dimension of the image section S at a given pixel i consists in:calculating the gradients of luminous intensity for all the pixels included in a neighbourhood Vi of pixel i,calculating a local gradient Gi from the gradient measurements obtained over the neighbourhood Vi and assigning the gradient Gi to pixel i,marching transversely from pixel to pixel starting from pixel i up to the vertical lateral boundaries of the image section S in the two directions indicated by the gradient Gi and its additive inverse −Gi, by iteratively repeating the previous two steps. 3. Method of chrono-stratigraphic interpretation of a seismic image block B comprising two horizontal dimensions, namely width and depth, and a vertical dimension or height in the direction of the subsoil and consisting of columns of pixels, consisting in:defining a block N identical in size to the image block B and consisting of elements each of which is associated with a pixel of the image block B and is initially assigned a zero value,for each pixel i of the image block B, calculating a continuity surface Si passing through the said pixel and transverse to the vertical dimension of the image block B,incrementing an element of the block N by one unit each time the pixel with which it is associated in the image block B is crossed by a surface Si,and characterized in that it furthermore consists in,constructing, for each column c of the block N, a histogram Hc consisting of a number of classes which is equal to the number of elements of the said column c, each class corresponding to one of the elements of the column c and conta ining a number of samples which is equal to the value aggregated in the relevant element of the block N, which value is equal to the number of surfaces passing through the pixel associated with the said element, the total number of samples distributed in the histogram constructed for each column being equal to the total number of pixels in the image block B,equalizing each histogram Hc so as to produce an equalized histogram Hc′,defining an empty image block B′, whose width in pixels and whose depth in pixels are identical to the width in pixels and to the depth in pixels of the image block B, and whose height in pixels is equal to the number of classes of the histograms Hc′,assigning the distribution defined by the equalized histogram Hc′ to each column c′ of the image block B′ by allocating each element of the column c′ the content of the associated class of Hc′,delimiting in the image block B′ the groups of contiguous pixels containing samples and labelling each of the said groups,allocating each pixel of the image block B the label given to the pixel group to which it was assigned in the image block B′ and displaying the labelled image block B. 4. Method according to claim 3, characterized in that the calculation of the continuity surface Si transverse to the vertical dimension of the image block B at a given pixel i consists in:calculating the gradients of luminous intensity for all the pixels included in a neighbourhood of each pixel i of a column of pixels Ki,for each pixel i of column Ki, performing a principal components analysis on the gradients calculated in the neighbourhood Vi of pixel i so as to determine a pair of direction vectors directed along the plane tangent to the surface Si at pixel i of column Ki,marching concentrically from column to column starting from column Ki up to the vertical lateral boundaries of the image block B, by iteratively repeating the previous two steps.