METHOD FOR DETERMINING FORMATION DENSITY AND FORMATION PHOTO-ELECTRIC FACTOR WITH A MULTI-DETECTOR-GAMMA-RAY TOOL

摘要

This invention is an advanced method for determining formation density in an array-detector density tool. The use of three or more detectors yields an improv ed accuracy and precision of the formation density measurement even in the presence of a large standoff between the tool and the formation. A more accurate photoelectr ic factor is determined through a new single detector algorithm. Use of the informa tion on the photoelectric effect and the density from the three detectors allows the measurement of a photoelectric effect compensated for stand off and the photoele ctric factor of the mudcake. The use of the multi-detector density answers allows for a consistency check and therefore a much improved quality control of the density measurement.