Movable oil measurement combining dual radio frequency induction and dual induction laterolog measurements

Claim 1

A method for determining the electromagnetic properties of earth formations in the vicinity of a well bore hole, the earth formations being invaded by conductive drilling fluid to form an invaded zone to some depth of invasion, comprising the steps of: determining by the use of conventional induction and resistivity well logs the resistance R xo of the invaded zone, the resistance R t , of the uninvaded formation, and the depth of invasion d i , as a function of depth in the well bore; measuring between a first spaced pair of locations in the well bore the relative phase shift of electromagnetic waves at a radio frequency in the range of 10-60 megahertz at a first relatively shallow radial depth of investigation primarily affected by the invaded zone and generating signals θ s representative thereof as a function of bore hole depth; measuring between a second spaced pair of locations in the well bore the relative phase shift of electromagnetic waves at a radio frequency in the range of 10-60 megahertz at a second relatively deeper radial depth of investigation affected primarily by the uninvaded formation and generating signals θ L representative thereof as a function of bore hole depth; and for each measured R xo , R t and d i , combining the signals θ s and θ L according to a predetermined relationship to derive indications of ε Xo , the dielectric constant of the invaded zone, and ε t , the dielectric constant of the uninvaded formation as a function of bore hole depth.

Claim 2

A method for determining the electromagnetic properties of earth formations in the vicinity of a well bore hole, the earth formations being invaded by conductive drilling fluid to form an invaded zone to some depth of invasion, comprising the steps of: determining by the use of conventional induction and resistivity well logs the resistance R xo of the invaded zone, the resistance R t , of the uninvaded formation, and the depth of invasion d i , as a function of depth in the well bore; measuring between a first spaced pair of locations in the well bore the relative phase shift of electromagnetic waves at a radio frequency in the range of 10-60 megahertz at a first relatively shallow radial depth of investigation primarily affected by the invaded zone and generating signals θ s representative thereof as a function of bore hole depth; measuring between a second spaced pair of locations in the well bore the relative phase shift of electromagnetic waves at a radio frequency in the range of 10-60 megahertz at a second relatively deeper radial depth of investigation affected primarily by the uninvaded formation and generating signals θ L representative thereof as a function of bore hole depth; and for each measured R xo , R t and d i , combining the signals θ s and θ L according to a predetermined relationship to derive indications of ε Xo , the dielectric constant of the invaded zone, and ε t , the dielectric constant of the uninvaded formation as a function of bore hole depth.

Claim 12

A method for determining electromagnetic properties of conductive well fluid invaded earth formations in the vicinity of a bore hole, the formations comprising a radially invaded zone and an uninvaded zone, comprising the steps of: generating, in a well bore hole, a radio frequency electromagnetic field in the frequency range from 10-60 megahertz; detecting in said well borehole the relative phase shift of the radio frequency field at the generated frequency between the coils of a first relatively short spaced receiver coil pair and generating a signal θ s representative thereof; detecting in said well borehole the relative phase shift of the radio frequency field at the generated frequency between the coils of a second relatively longer spaced receiver coil pair and generating and a signal θ L representative thereof; determining by means of conventional low frequency induction and resistivity well logging techniques R xo , the resistivity of the invaded zone, R t , the resistivity of the uninvaded formation and d i the depth of invasion; and combining the θ s and θ L representative signals according to a predetermined relationship as a function of R xo , R t and d i to derive indications of ε xo , the dielectric constant of the invaded zone and ε t , the dielectric constant of the uninvaded formation.

Claim 13

A method for determining electromagnetic properties of conductive well fluid invaded earth formations in the vicinity of a bore hole, the formations comprising a radially invaded zone and an uninvaded zone, comprising the steps of: generating, in a well bore hole, a radio frequency electromagnetic field in the frequency range from 10-60 megahertz; detecting in said well borehole the relative phase shift of the radio frequency field at the generated frequency between the coils of a first relatively short spaced receiver coil pair and generating a signal θ s representative thereof; detecting in said well borehole the relative phase shift of the radio frequency field at the generated frequency between the coils of a second relatively longer spaced receiver coil pair and generating and a signal θ L representative thereof; determining by means of conventional low frequency induction and resistivity well logging techniques R xo , the resistivity of the invaded zone, R t , the resistivity of the uninvaded formation and d i the depth of invasion; and combining the θ s and θ L representative signals according to a predetermined relationship as a function of R xo , R t and d i to derive indications of ε xo , the dielectric constant of the invaded zone and ε t , the dielectric constant of the uninvaded formation.