Patent ID: 7457707

Claim:
A method for correcting induction conductivity well log measurements for conductivity of a wellbore and a formation proximate the wellbore, comprising: estimating an effective formation conductivity for the formation proximate the wellbore from measurements made by an induction receiver proximate an induction transmitter; wherein the estimating effective formation conductivity comprises selecting an initial value of the effective formation conductivity and iteratively calculating estimates of the effective formation conductivity using an output of each iterative calculation as input to successive iterative calculations thereof, using the effective formation conductivity to correct apparent conductivity measurements made by at least one induction receiver on the instrument wherein the iteration is performed according to the expression: σ t ( J + 1 ) = σ R - σ m ⁢ g R ⁡ ( r b , d , σ m , σ t ( J ) ) 1 - γ ⁡ ( σ t ( J ) ) - g R ⁡ ( r b , d , σ m , σ t ( J ) ) , wherein σ t is the effective formation conductivity, J is an iteration step index, σ t (J) is the J-th approximation of σ t , σ t (0) is the initial value of effective formation conductivity, σ R is the real part of the apparent conductivity determined from the proximate receiver measurements, r b is a wellbore radius, d is an amount of displacement of a well logging instrument from a center of the wellbore, σ m is conductivity of a fluid in the wellbore, γ(σ t ) the skin-effect magnitude for the effective formation conductivity, and g R (r b ,d,σ m ,σ t ) is a pseudo-geometrical borehole correction factor.