Preliminary Experiment Research On Rock Physics Of Sweep-Frequency Dielectric Logging

The dielectric constant of water is very different from the dielectric constant of oil or rock-frame.The difference of the significant dielectric constant of oil and water can solve the problem of low-contrast oil layer which can not be solved by conventional resistivity logging.In this paper,the development situation of foreign dielectric logging is investigated and analyzed.A series of research on rock dielectric experiment have been carried out,combined with the present situation in our country.The aim is to provide theory for the new method of dielectric logging in China.In this paper,firstly,the theory of rock dielectric constant and the mechanism of internal polarization are analyzed.Meanwhile,several measurement methods of sweepfrequency dielectric are studied and a total of seven round experiment are carried out.In view of the purpose of the study,the design of the pilot scheme of sweep-frequency dielectric is carried out.Two different experimental schemes are determined in the radio frequency section and the broadband frequency section.Shielding parallel plate capacitors method is used for the radio frequency section and coaxial probe method is used for broadband frequency section.A pervasive model is selected to deal with dielectric experimental and the influence factors of rock cementation exponent are analyzed.At the same time,the relationships between the dielectric constant of rock and salinity,porosity,cementation exponent or saturation are explored to establish the dielectric properties of rock.Finally,previous dielectric constant interpretation laws are analyzed.Maxwell-Garnett law is improved to apply to pure sandstone and the accuracy of the law is confirmed.