SIMULTANEOUS THERMAL NEUTRON DECAY TIME AND SHALE COMPENSATED CHLORINE LOG SYSTEM

摘要

SIMULTANEOUS THERMAL NEUTRON DECAY TIMEAND SHALE COMPENSATED CHLORINE LOG SYSTEMD#73,880-FABSTRACT OF THE DISCLOSURE:Earth formations surrounding a well borehole arerepetitively bombarded with bursts of high energy neutrons.A radiation detector in a sonde in the borehole senses thegamma rays induced by the capture of thermal neutrons andsends representative signals to the surface. At the surfaceelectronics, the population of thermal neutron capture gammarays at two separate and distinct times is measured. Themacroscopic thermal neutron capture cross section of theformation may be thus determined and logged. Further, twoadditional single channel energy analyzers, such as from1.30 to 2.92 Mev and from 3.43 to 10.0 Mev, sense formationcapture gamma ray response over a common time intervalfollowing each neutron burst. The measurements made inthese two additional single channel analyzers are used todistinguish between the presence of salt water and hydrocar-bons in the formation, which is also logged.I