METHOD AND APPARATUS FOR DETERMINING TRUE FORMATION POROSITY FROM MEASUREMENT-WHILE-DRILLING NEUTRON POROSITY MEASUREMENT DEVICES

摘要

Abstract of the DisclosureA method and apparatus for determining true formationporosity utilize downhole measurement-while-drilling neutronporosity measurement devices. A initial measurement is takenshortly after the formation is bored and before any substantialinvasion by the drilling fluid occurs. Subsequent measurementsare made until a steady, no longer increasing, measurement isreached indicating saturation of the formation by the drillingfluid to the depth of the measurements. The difference betweenthe initial and steady measurements is indicative of the trueporosity of a gas containing formation.