Method for determining irregularities in a wellbore wall using a gamma-gamma well logging instrument

A method for determining a profile of a wall of a wellbore drilled through earth formations from measurements of scattered gamma rays detected at spaced apart locations from a source of said gamma rays, at least one of said axially spaced apart locations positioned on an opposite side of said source from other ones of said spaced apart locations, the method comprising:

• calculating a function related to a rate of detecting said scattered gamma rays at a first one of said spaced apart locations with respect to a rate of detecting said scattered gamma rays at said at least one spaced apart location positioned on said opposite side of said source;
• determining density of said earth formations and density of fluid in said wellbore and a difference between said densities;
• determining an area bounded by said function;
• scaling said area with respect to said difference between said densities;
• and
• calculating said profile from said scaled area bounded by said function.

A method for determining a profile of a wall of a wellbore drilled through earth formations, comprising:

• irradiating said earth formations with a source of gamma rays;
• initially detecting scattered gamma rays at a predetermined axial spacing from said source;
• recording measurements of said detecting;
• subsequently detecting said scattered gamma rays, at said predetermined axial spacing, after said source has moved a predetermined distance;
• calculating a function related to a rate of detecting said scattered gamma rays during said step of initially detecting with respect to said step of subsequently detecting;
• determining density of said earth formations and density of fluid in said wellbore and a difference between said densities;
• determining an area bounded by said function;
• scaling said area with respect to said difference between said densities;
• and
• calculating said profile from said scaled area bounded by said function.

A method for determining a profile of a wall of a wellbore drilled through earth formations from measurements of scattered gamma rays initially detected at a spaced apart location from a source of said gamma rays, and measurements of scattered gamma rays subsequently detected at said spaced apart location from said source when said source has moved a predetermined distance, the method comprising:

• calculating a function related to a rate of said initially detecting said scattered gamma rays with respect to a rate of said subsequently detecting said scattered gamma rays;
• determining density of said earth formations and density of fluid in said wellbore and a difference between said densities;
• determining an area bounded by said function;
• scaling said area with respect to said difference between said densities;
• and
• calculating said profile from said scaled area bounded by said function.