Method for elaborating pseudo-logs of image of well walls from photographs of geological outcrops

Abstract

The present invention relates to a method for defining logs of image of well walls from photographs of geological outcrops. The objectives of the present invention are related to the creation of a flat projection of a pseudo-cylinder originating from longitudinal 2D images of available photographs of geological outcrops. By means of the present invention, said created projection can be used by specific intelligence mechanisms, obtaining pseudo-logs of image for correlation with real logs of image. This solution, unlike the state of the art, allows obtaining pseudo-logs of image at low cost.

1 . A method for defining pseudo-logs of an image of well walls from photographs of geological outcrops, comprising the following steps:
 Step a) Selecting a photographic image of a geological outcrop;   Step b) Cropping the photographic image of the geological outcrop;   Step c) Performing the extrusion of the image of the photographic crop of the geological outcrop;   Step d) Cutting a cylindrical shell from the volume formed;   Step e) Performing a flat projection of the cylindrical shell;   Step f) Saving the new image constructed from the projection of the cylinder of a 2D plane; and   Step g) Applying geophysical log analysis.   
     
     
         2 . The method of  claim 1 , wherein the selection of the photographic image of a geological outcrop in Step a) comprises, determining the base photographic image, whose longitudinal section of a photographic crop on this base image will be transformed into a flat projection of a cylindrical pseudo-log. 
     
     
         3 . The method of  claim 1 , wherein the selection of the photographic image of the geological outcrop of Step a) preferably occurs with the image presenting the expected dimensions of an outcrop photo crop for comparison with the well wall. 
     
     
         4 . The method according to  claim 1 , wherein the selection of the photographic image of the geological outcrop of Step a) preferably occurs with the geological structures under investigation visible in outcrop photographs to the naked eye on a computer screen. 
     
     
         5 . The method of  claim 1 , wherein the selection of the photographic image of the geological outcrop of Step a) preferably occurs with the scale of the photo known, so that a crop of precise size and known dimensions can be performed. 
     
     
         6 . The method of  claim 1 , wherein the selection of the photographic image of the geological outcrop of Step a) preferably occurs with the resolution being greater than 120 dpi. 
     
     
         7 . The method of  claim 1 , wherein the cropping of Step b) is performed using a commercially available image viewing or vector illustration graphic design program, the said crop having a width relative to the diameter of the wall of the investigated well. 
     
     
         8 . The method of  claim 1 , wherein in Step c) of performing the extrusion of the image of the photographic crop of the geological outcrop forming a volume is performed mathematically, preferably in a Python environment. 
     
     
         9 . The method of  claim 1 , wherein in Step d), the cylindrical shell is cropped mathematically in a Python environment, the amplitudes in the cylindrical shell, located in terms of the cylindrical coordinates rho (ρ), theta (θ) and z, are obtained through the interpolation of the pixel values of the original photo, considering that the same pixel repeats itself indefinitely along the extrusion direction; the projected pseudo-log of image is obtained by sectorizing the theta (θ) coordinate into the number of chosen sectors (for example, every 3 degrees, totaling 120 sectors), for each slice of the original image along the z coordinate; however, for theta (θ) angles close to 0° and 180°, sampling is performed every 6°, and if this procedure reduces the total number of sectors, the resulting image is interpolated to return to having a width of 120 pixels. 
     
     
         10 . The method of  claim 1 , wherein in Step e), the cylindrical shell cropped in Step d) is projected onto a plan, achieving a flat projection of a cylindrical pseudo-log ( 24 ). 
     
     
         11 . The method of  claim 1 , wherein in Step f), the image achieved in Step e) is saved in the digital formats jpg, tif, png, or other available digital formats. 
     
     
         12 . The method according to  claim 1 , characterized in that, in Step g), the image saved of Step f) is loaded into an intelligence mechanism for analyzing geophysical logs, such that it preferably has a module that converts the figure of the flat projection of the pseudo-cylinder into matrices with RGB values;
 wherein the image of the pseudo-cylinder converted into a matrix of values in Step f) is capable of being recognized in intelligence mechanisms that have petrophysical interpretation capacity, as it has the same format as a log of image, as well as being capable of being viewed with the same color scale and being horizontally rotated, in relation to the position of the cylinder that one wishes to observe, between 0° and 360°.