Memory gravel pack imaging apparatus and method

A method of evaluating degree of gravel pack in a predefined annulus between a tubing and well bore inside, comprising:

• providing a down hole tool at an end of a conveying member, said tool adapted to record data in a memory in said tool corresponding to nuclear energy generated by a source and received by at least one (1) scintillation detector carried by said tool in response to said nuclear energy generated by said source thereof in said annulus, wherein the size of said source and scintillation detector are chosen to produce a relatively large density count rate wherein the counts are substantially due to the energy of the source and a much smaller percentage of the counts are due to radioactive materials injected into the formation;
• injecting radioactive materials into a formation;
• locating said down hole tool at a predetermined location in said well bore;
• packing said annulus with gravel;
• detecting the azimuthal orientation of the detector in the down hole tool with respect to an orientation package in the tool;
• locating imperfections with reference to the detector with respect to the high or low side of the well bore;
• quantifying imperfections in a gravel pack as a percent of a circumference of a packed or unpacked areas;
• and
• recording said data in said memory while moving said tool along said annulus by said conveying member.