Borehole imaging

Method of detecting significant events intersecting a borehole from an image of the borehole wall, which image comprises a two-dimensional array of numbers, each number being the magnitude of a relevant borehole parameter at a point defined by the circumferential direction and the depth, which method comprises the steps of:

• (a) converting the image into a three-dimensional orientation space consisting of a stack of two-dimensional images, wherein each two-dimensional image is obtained by applying an edge-detecting or line-detecting filter to the image with a particular orientation of the filter;
• (b) selecting a parameter relation that represents the intersection of an event with the borehole wall, wherein the intersection is characterized by n parameters;
• (c) creating an n-dimensional parameter space consisting of numbers as a function of the n parameters, wherein each number is a measure of the support in the orientation space for an intersection characterized by the parameters that pertain to that number;
• (d) selecting in the parameter space a set of the largest numbers, wherein the parameters that pertain to each of these largest numbers represent well supported intersections with the borehole wall;
• and
• (e) presenting the intersections pertaining to the set of the largest numbers as a list of data representing significant events.