Patent ID: 8775084

Claim:
A method for determination of properties near a borehole with measured galvanic data, the method comprising: inputting measured galvanic data, MLRx meas , wherein MLRx meas is a variable for measured galvanic data, from a plurality of log measurements from a logging tool in a borehole, calculating a corrected measured galvanic data measurement MLRx cor wherein MLRx cor is calculated by correcting the measured galvanic data, MLRx meas by multiplying the measured galvanic data MLRx meas by a correction ratio, MLRx cor = MLRx meas · MLRx ⁡ ( Rm = Rxo , BHD , Ecc , Rxo , Lxo , Rt ) MLRx ⁡ ( Rm , BHD , Ecc , Rxo , Lxo , Rt ) wherein MLRx cor is the corrected galvanic measurement for sub-array x (x=1, 2, 3, or 4); MLRx meas is the field measurement for sub-array x; and MLRx(Rm,BHD,Ecc,Rxo,Lxo,Rt) is the calculated response for sub-array x for specified parameters where Rm is measured by TTRM mud resistivity; and MLRx(Rm=Rxo,BHD,Ecc,Rxo,Lxo,Rt) is the calculated response for sub-array x for specified parameters where Rxo value is used for the mud resistivity value; wherein BHD is borehole diameter, Ecc is tool eccentricity, Rt is formation resistivity, Rxo is invasion resistivity, and Lxo is depth of invasion, wherein the correction ratio is calculated utilizing a first inversion wherein a mud resistivity is set equal to an invasion resistivity Rxo and a second inversion wherein the mud resistivity is set equal to a measured mud resistivity Rm; and determining, using inversion of the galvanic data and bore hole correction parameters, prior to bore hole correction of the galvanic data, at least one resistivity value and at least one tool eccentricity value from the plurality of log measurements, wherein said determining comprises determining multiple resistivity values, wherein said multiple resistivity values include formation resistivity and invasion resistivity.