关键词: 测井, 反演, 侵入, 时间, 电阻率, 饱和度

Abstract: The process of drilling mud filtrate invading into an oil/gas reservoir is related to invasion time after the bed was penetrated,hence the reading of a resistivity logging tool is a function as time.Prior resistivity inversion algorithms are based on an over-simple step-invasion model,so they cannot give a realistic invasion image,furthermore,the inversion results must be influenced by the ideal invasion model.The present inversion of time-lapse logging holds fluid-and formation-related parameters that control the dynamic invasion process in the model.Therefore,it is able to exhibit the dynamic characters of a realistic invasion process and provides more information for researchers to evaluate a reservoir.Since the present model is sensitive to the variation of saturation,mud property,drilling condition and so on,a reservoir can be evaluated through matching time dependent field logging data.Original water saturation(or true formation resistivity) and mud cake permeability are regarded as unknown parameters to be determined from the inversion routine.Field applications for dual-induction logging illustrate that the present model is a reasonable and efficient method for reservoir evaluation.

Key words: well logging, inversion, invasion, time, resistivity, saturation