PHYSICAL MODELING FOR DENSITY MEASUREMENT OF NEAR-SURFACE ROCKS, BY WIRELINE LOGGING AND LOGGING WHILE DRILLING

The results of the creation of full-scale physical models of rocks for the calibration of combined tools of radioactive logging, which include density logging, are presented. Four sets of models were built for different logging problems. 1. Models of porous carbonate reservoirs with borehole (diameter 216 mm), equipped with interchangeable simulators of casing columns (146 mm i 168 mm) with cement sheath and tubing. The models are aimed to calibrate wireline logging tools for investigating the section of uncased and cased oil&gas wells. 2. Models of rocks of different density with borehole (160 mm), equipped with interchangeable drill collars (120 mm, 108 mm, 89 mm). The models are designed to calibrate density tools for logging while drilling horizontal oil&gas wells. 3. Universal models of porous carbonate reservoirs, crossed by holes of three diameters (200 mm, 160 mm, 125 mm). The purpose of the models is to calibrate wireline logging tools for investigation of section of uncased and cased oil&gas wells and tools for logging while drilling horizontal oil&gas wells. 4. Models of near-surface rocks of different density, equipped with a steel pipe (diameter of 51 mm) closely fitting to rock The purpose of She models is to calibrate density tools for investigation of near-surface rocks when solving engineering-geological, seismic microzoning, ecological, etc problems. Physical models were designed and constructed by the employees of the Institute of Geophysics of the National Academy of Sciences of Ukraine together with partner organizations. The regular use of the models is due to the active work carried out by the Institute of Geophysics, together with partners, to create apparatus-methodical complexes of radioactive logging, which include the density logging. Graduation relationships and calibration functions for new density logging tools, obtained on the constructed physical models, as well as examples of density determination in different well conditions when solving research-and-production problems, are given.