FORMATION DENSITY WELL LOGGING TOOL WITH DETECTOR ARRAY FOR COMPENSATION OF WELLBORE ROUGHNESS AND TOOL TILT

摘要

A method for determining density of a formation. The method includesirradiating the formation with gamma rays having energy consistent withComptonscattering. Gamma rays are measured at axially spaced apart locations. Two oftheaxially spaced apart locations are at an equal distance and in oppositedirections relativeto the source of gamma rays. The distance is smaller than the spacing ofanother oneof the spaced apart locations. An apparent density for each spaced apartlocation isdetermined from the counts. Differences are calculated in apparent densitybetweeneach one of the spaced apart locations, and a correction factor is determinedforapparent density at each spaced apart location, thereby determining thedensity of theearth formation. In a preferred embodiment, determining correction factors isperformed by a neural network using the differences in apparent density as aninputvector.