Forward Modeling Of The Frequency Sweep Dielectric Log

Dielectric logging has been efficiently used in low contrast reservoir identification due to the difference of dielectric constant of the fluid in the rock.Because of the environmental constraints and numbered stratigraphic information acquired,the traditional measurements of dielectric logging are seldom used.Based on the traditional tools and dielectric dispersion,the frequency sweep dielectric logging provides more information for reservoir identification.In this paper,the dielectric dispersion mechanism and the measuring principle of the tool are introduced.The responses of the tool are simulated by analytic method,as well as the three dimensional finite element method.The investigation characteristic and the influence of mud cake are analyzed at the last part of the paper.The responses of the frequency sweep dielectric logging tool,which is simplified as dipole resource,in homogeneous layer and homogeneous half-space are simulated by the analytic method.The composite wave model is put forward based on the dipole model.Compared to the dipole model,the composite wave model is more efficient and applicable.The influence of operating frequency and antennas array structure are analyzed.As a result,the operating frequency and antennas array structure are designed at last.The slot antenna with backed resonant is designed as transmitting antennas and receiving antenna of the frequency sweep dielectric logging tool by using the three dimensional finite element method.The responses of antennas in homogeneous layer are modeling,and the results has been compared to the analytical solution to demonstrate the correctness of the arithmetic.The conversion charts of homogeneous layer are made at last.The study on the investigation depth and bed resolution of the frequency sweep dielectric logging is carried out in this paper.The influence of mud cake and shoulder bed are analyzed,and the correction charts have been made at last based on the results above.