Method and system for analyzing cuttings coming from a wellbore

A system for analyzing cuttings exiting a borehole comprising

• an imaging device for taking at least an image of a sample of cuttings on a background surface
• a calculator configured to, for at least one of the images:
• obtain at least a spectrum representative of the image in the (hue, saturation, brightness) coordinate space, wherein each spectrum is associated to a coordinate and is representative of the distribution of the values of the pixels for said coordinate,
• assign a set of reference values relative to the predetermined coordinate to at least a group, wherein the set comprises at least one value, wherein each group is representative of a type of objects within the image, at least one group being representative of the cuttings while one group is representative of the background surface, wherein assigning a set of reference values comprises deriving at least one calibration background reference value relative to the predetermined coordinate from values of calibration pixels for the predetermined coordinate, wherein the calibration pixels are obtained either by selecting one or several pixels of the image situated in a section of the image representative of the background surface or by taking an image of the background surface containing no cuttings,
• based on the at least one spectrum and the values of each pixel for the at least one associated coordinate, classify said pixel in one of a plurality of groups, wherein the classification comprises comparing the value of each pixel for the predetermined coordinate to the set of reference values assigned to at least one group,
• determine at least a cuttings zone in the image based on the classification of the pixels.

A non-transitory computer-readable medium for analyzing cuttings exiting the wellbore based on an image of a sample of the cuttings on a background surface, storing machine-readable instructions to:

• obtain at least a spectrum representative of the image in the (hue, saturation, brightness) coordinate space, wherein each spectrum is associated to a coordinate and is representative of the distribution of the values of the pixels for said coordinate,
• assign a set of reference values relative to the predetermined coordinate to at least a group, wherein the set comprises at least one value, wherein each group is representative of a type of objects within the image, at least one group being representative of the cuttings while one group is representative of the background surface, wherein assigning a set of reference values comprises deriving at least one calibration background reference value relative to the predetermined coordinate from values of calibration pixels for the predetermined coordinate, wherein the calibration pixels are obtained either by selecting one or several pixels of the image situated in a section of the image representative of the background surface or by taking an image of the background surface containing no cuttings,
• based on the at least one spectrum and the values of each pixel for the at least one associated coordinate, classify said pixel in one of a plurality of groups, wherein the classification comprises comparing the value of each pixel for the predetermined coordinate to the set of reference values assigned to at least one group,
• determine at least a cuttings zone in the image based on the classification of the pixels.