Method of detecting gas in a formation using capture cross-section from a pulsed neutron device

摘要

Elemental analysis of an earth formation is performed using measurements from a gamma ray logging tool. From the elemental analysis, an estimate of the mineralogy of the formation is made. A prediction of the capture cross-section of the formation is made using the mineralogical analysis. The difference between the predicted capture cross-section and a measured capture cross-section is an indication of gas in the formation.