Detection Performance Analysis of Array Dielectric Dispersion Logging Based on Sensitivity Function

Abstract

Dielectric logging is a critical method for exploring and developing complex oil and gas reservoirs, such as tight reservoirs, low-resistivity contrast reservoirs, and shale oil and gas reservoirs. The sensitivity function is extended to high-frequency dielectric logging in this paper. The detection characteristics of attenuation and phase shift of an array dielectric logging tool in different modes are investigated, along with the influencing factors such as resistivity and dielectric constant. The results show the following: (1) The symmetrical coil system structure makes the sensitivity distribution symmetrically distributed, and the detection range is more focused. In the same measurement mode, the depth of investigation (DOI) becomes deeper under high resistivity formation, and the sensitivity range oscillates outward when the dielectric constant becomes greater. (2) The DOIs of different frequencies and source spacings cover the radial zone between 1 cm and 15 cm. The detection range has been enlarged to include part of the invasion zones, improving the measurement data’s dependability. (3) With the increase in the dielectric constant, the curve tends to oscillate, and this behavior makes the DOI slightly shallower. Additionally, this oscillation phenomenon is obvious when the frequency, resistivity, and dielectric constant increase, particularly in high-frequency detection mode (F2, F3).