Pulsed radioactive well logging method for measurement of porosity and salinity

Claim 1

A METHOD OF INVESTIGATING FORMATIONS TRANSVERSED BY A BOREHOLE FOR TWO PARAMETERS OF INTEREST AND OF A DIFFERENT NATURE COMPRISING THE STEPS OF PASSING INTO THE BOREHOLE A LOGGING TOOL CONTAINING A SOURCE OF PRIMARY RADIATION, IRRADIATING THE FORMATIONS WITH BURSTS OF PRIMARY RADIATION SPACED IN TIME FOR THE PRODUCTION OF SECONDARY RADIATION AT A FIRST LOCATION SPACED FROM THE SOURCE DETECTING SECONDARY RADIATION PASSING FROM THE FORMATIONS INTO THE BOREHOLE, AT A SECOND LOCATION SPACED FROM THE SOURCE BY A DIFFERENT DISTANCE DETECTING SECOND RADIATION PASSING FROM THE FORMATIONS INTO THE BOREHOLE, PRODUCING IN CORRELATION WITH DEPTH A FIRST MEASUREMENT REPRESENTATIVE OF THE SECONDARY RADIATION DETECTED AT THE FIRST LOCATION FOLLOWING EACH BURST OF PRIMARY RADIATION, PRODUCING IN CORRELATION WITH DEPTH A SECOND MEASUREMENT REPRESENTATIVE OF THE SEONDARY RADIATION DETECTED AT THE SECOND LOCATION FOLLOWING EACH BURST OF PRIMARY RADIATION, FROM THE FIRST AND SECOND MEASUREMENTS PRODUCING FIRST AND SECOND FUNCTIONS CHARACTERIZING THE SECONDARY RADIATION DETECTED RESPECTIVELY AT THE FIRST AND SECOND LOCATIONS, RECORDING A THIRD FUNCTION REPRESENTATIVE OF THE DIFFERENCE BETWEEN THE FIRST AND SECOND FUNCTIONS TO OBTAIN A MEASUREMENT OF ONE OF THE PARAMETERS OF INTEREST, AND FROM ONE OF THE FIRST AND SECOND MEASUREMENTS RECORDING A FUNCTION CHARACTERIZING THE SECONDARY RADIATION DETECTED AT ONE OF SAID LOCATIONS FOR COMPARISON WITH THE PARAMETER MEASURED FOR OBTAINING INFORMATION ABOUT THE OTHER OF THE TWO PARAMETERS OF INTEREST.

Claim 2

A METHOD OF INVESTIGATING FORMATIONS TRANSVERSED BY A BOREHOLE FOR TWO PARAMETERS OF INTEREST AND OF A DIFFERENT NATURE COMPRISING THE STEPS OF PASSING INTO THE BOREHOLE A LOGGING TOOL CONTAINING A SOURCE OF PRIMARY RADIATION, IRRADIATING THE FORMATIONS WITH BURSTS OF PRIMARY RADIATION SPACED IN TIME FOR THE PRODUCTION OF SECONDARY RADIATION AT A FIRST LOCATION SPACED FROM THE SOURCE DETECTING SECONDARY RADIATION PASSING FROM THE FORMATIONS INTO THE BOREHOLE, AT A SECOND LOCATION SPACED FROM THE SOURCE BY A DIFFERENT DISTANCE DETECTING SECOND RADIATION PASSING FROM THE FORMATIONS INTO THE BOREHOLE, PRODUCING IN CORRELATION WITH DEPTH A FIRST MEASUREMENT REPRESENTATIVE OF THE SECONDARY RADIATION DETECTED AT THE FIRST LOCATION FOLLOWING EACH BURST OF PRIMARY RADIATION, PRODUCING IN CORRELATION WITH DEPTH A SECOND MEASUREMENT REPRESENTATIVE OF THE SEONDARY RADIATION DETECTED AT THE SECOND LOCATION FOLLOWING EACH BURST OF PRIMARY RADIATION, FROM THE FIRST AND SECOND MEASUREMENTS PRODUCING FIRST AND SECOND FUNCTIONS CHARACTERIZING THE SECONDARY RADIATION DETECTED RESPECTIVELY AT THE FIRST AND SECOND LOCATIONS, RECORDING A THIRD FUNCTION REPRESENTATIVE OF THE DIFFERENCE BETWEEN THE FIRST AND SECOND FUNCTIONS TO OBTAIN A MEASUREMENT OF ONE OF THE PARAMETERS OF INTEREST, AND FROM ONE OF THE FIRST AND SECOND MEASUREMENTS RECORDING A FUNCTION CHARACTERIZING THE SECONDARY RADIATION DETECTED AT ONE OF SAID LOCATIONS FOR COMPARISON WITH THE PARAMETER MEASURED FOR OBTAINING INFORMATION ABOUT THE OTHER OF THE TWO PARAMETERS OF INTEREST.