Study And Application Of Environmental Factor Correction For Dual Laterologs In Horizontal Well

When measuring inclined and horizontal Wells with dual laterolog instruments,environmental factors such as expanding,invasion,drilling fluid density and salinity,shoulder bed thickness,and shoulder bed resistivity will affect the fluctuation of apparent resistivity.These environmental factors make logging interpretation and data processing difficult,so environmental factors should be corrected for logging curves.Because the formation media has no rotational symmetry when the dual laterolog instrument is used to measure the inclined and horizontal Wells,the logging curve is different from the conventional logging curve,so it is difficult to directly reflect the formation information.The traditional correction chart and interpretation method cannot explain the real situation of the formation,so it is necessary to conduct 3d forward modeling and research on the logging response characteristics of inclined and horizontal Wells.The environmental factor correction chart and correction program are made to help the log interpreters to process and evaluate the logging curves.In this paper,the finite element method is used to calculate the electric field of 2d and 3d formation models,and the forward numerical simulation of dual laterolog is realized.Firstly,based on the numerical simulation results of forward modeling,the effects of environmental factors such as borehole diameter,layer thickness,well deviation and invasion are analyzed,and the corresponding understanding of logging response law is summarized.Then,the forward numerical simulation program is used to make the apparent resistivity borehole correction chart for dual laterolog,the deviation-thickness/shoulder bed correction chart for dual laterolog and the apparent resistivity intrusion correction chart for dual laterolog.Finally,according to the resistivity correction chart based on CIFLog logging interpretation software design of dual laterolog response to environmental factors correction module,stratigraphic model response to make use of the module calibration,the accuracy of the method is verified feasible.Under certain conditions the module can replace the traditional manual correction,fast accurate calibrate dual laterolog response to environmental factors.Partly remove borehole diameter,layer thickness,well deviation,into the influence of environmental factors,such as to obtain the true resistivity of the formation,for accurate calculation of reservoir parameters,for judging the laminar liquid to provide reliable electrical parameters.