Baker Hughes Corporation

Berthold Kriegshauser

Otto N Fanini

Liming Yu

Richard A Mollison

Stanislav W Forgang

Gulamabbas A Merchant

Milomir Pavlovic

Juergen S Schoen

Pravin Gupta

Tsili Wang

Leonty Abraham Tabarovsky

Xiao Ming Tang

Zhiyi Zhang

Jiaqi Xiao

Steve McWilliams

An improved induction tool for evaluating formation resistivity. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. A magnetic lens is provided to select sensitivity to a desired reservoir formation property.

Method and apparatus for mulit-component induction instrument measuring system for geosteering and formation resistivity data interpretation in horizontal, vertical and deviated wells

Measurements made with a multicomponent logging instrument when used in a substantially horizontal borehole in earth formations provide diagnostic of the direction of beds relative to the position of the borehole. When the logging instrument is conveyed on a drilling assembly, the drilling trajectory may be maintained to follow a predetermined trajectory or to maintain a desired distance from a boundary such as an oil-water contact.

Method and apparatus for the use of multicomponent induction tool for geosteering and formation resistivity data interpretation in horizontal wells

Measurements made with a multicomponent logging instrument when used in a substantially horizontal borehole in earth formations are diagnostic of the direction of beds relative to the position of the borehole. When the logging instrument is conveyed on a drilling assembly, the drilling trajectory may be maintained to follow a predetermined trajectory or to maintain a desired distance from a boundary such as an oil-water contact.

An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. Various transmitter receiver combinations are provided to select sensitivity to a desired reservoir formation properties, for example, different orientations xy, xz, yz, 20-40, 20-90, and combinations, such as, Symmetric-symmetric; Asymmetric-symmetric; and Asymmetric-asymmetric. Measurements made with a multi-component logging instrument when used in a substantially horizontal, vertical or deviated borehole in earth formations are diagnostic of the direction of resistive beds relative to the position of the borehole.

Method and apparatus for a multi-component induction instrument measuring system for geosteering and formation resistivity data interpretation in horizontal, vertical and deviated wells

Measurements made by a cross-dipole acoustic logging tool in a borehole are processed to determine the principal directions of azimuthal anisotropy of a subsurface formation. Measurements indicative of azimuthal resistivity variations are also made with a multicomponent induction logging tool. These electrical measurements are processed using the principal direction determined from acoustic measurements to give an estimate of azimuthal resistivity variations. Based on modeling results, azimuthal resistivity variations are interpreted to estimate a fracture depth in the rock for known fluids therein.

Method of using electrical and acoustic anisotropy measurements for fracture identification

An improved induction tool for formation resistivity evaluations. The tool provides electromagnetic transmitters and sensors suitable for transmitting and receiving magnetic fields in radial directions that are orthogonal to the tool's longitudinal axis with minimal susceptibility to errors associated with parasitic eddy currents induced in the metal components surrounding the transmitter and receiver coils. Various transmitter receiver combinations are provided to select sensitivity to a desired reservoir formation properties, for example, different orientations xy, xz, yz, 20-40, 20-90, and combinations, such as, Symmetric&#x2014;symmetric; Asymmetric&#x2014;symmetric; and Asymmetric&#x2014;asymmetric. Measurements made with a multi-component logging instrument when used in a substantially horizontal, vertical or deviated borehole in earth formations are diagnostic of the direction of resistive beds relative to the position of the borehole.

Data are acquired using multi-array logging tool in a borehole having an angle of inclination to a normal to the bedding plane of earth formations. The multi-array measurements are filtered using angle dependent filters to give a filtered curve corresponding to a target one of the multi-array measurements using angle dependent filters. Correlation coefficients are determined for a set of possible dip angles and a relative dip angle is estimated from the correlation coefficients. This dip angle estimate together with bed boundaries obtained from the multi-array measurements are used for inverting multi-component measurements alone or jointly with multi-array measurements to refine the relative dip angle interpretation and give horizontal and vertical formation resistivity.

Method for joint interpretation of multi-array induction and multi-component induction measurements with joint dip angle estimation

The total porosity of said formation, a fractional volume of the shale, and a resistivity of the shale are determined in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data. The volume of dispersed shale and the total and effective porosities of the laminar sand fraction are determined using a Thomas-Stieber-Juhasz approach. Removal of laminar shale conductivity and porosity effects reduces the laminated shaly sand problem to a single dispersed shaly sand model to which the Waxman-Smits equation can be applied.

Water saturation and sand fraction determination from borehole resistivity imaging tool, transverse induction logging and a tensorial water saturation model

Measurements made by a multicomponent logging tool in a borehole are inverted to obtain horizontal and vertical resistivities and formation dip and azimuth angles of a formation traversed by the borehole. The inversion is performed using a generalized Marquardt-Levenberg method. In this generalized Marquardt-Levenberg method, a data objective function is defined that is related to a difference between the model output and the measured data. The iterative procedure involves reducing a global objective function that is the sum of the data objective function and a model objective function related to changes in the model in successive iterations. In an alternate embodiment of the invention, the formation azimuth angle is excluded from the iterative process by using derived relations between the multicomponent measurements.

Simultaneous determination of formation angles and anisotropic resistivity using multi-component induction logging data

A fast, efficient and accurate pseudo 2-D inversion scheme for resistivity determination of an anisotropic formation uses data from a tool (3DEX) comprising three transmitters and three corresponding receivers sampling the formation in a plurality of spatial directions. An initial model of the formation including invasion zones is obtained using a conventional multifrequency and/or multispacing logging tool. A pseudo 2-D inversion scheme combines an accurate full 2-D forward solution of the synthetic responses of the earth model with a 1-D approximation of the sensitivity matrix of the horizontally layered anisotropic background model. The timesaving compared to a regular 2-D inversion scheme can be tremendous. The applicability of this scheme is important in cases when borehole and near-zone effects do not allow an interpretation based on 1-D inversion. A comparison of the pseudo 2-D inversion scheme versus a full 2-D inversion using a realistic synthetic example shows that the pseudo 2-D inversion scheme performs as well as the full 2-D inversion, but in a much shorter time.

Efficient and accurate pseudo 2-D inversion scheme for multicomponent induction log data

Shoulder corrections are applied to measurements obtained from a multi-component electromagnetic logging tool. An anisotropic resistivity model is obtained using the shoulder corrected data. The process is iterated until a good match is obtained between the shoulder corrected data and the model output.

Method for determination of apparent resistivities of anisotropic reservoirs

The total porosity of a formation, a fractional volume of the shale, and a resistivity of the shale are determined in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data. The volume of dispersed shale and the total and effective porosities of the laminar sand fraction are determined using a Thomas-Stieber-Juhasz approach. Removal of laminar shale conductivity and porosity effects reduces the laminated shaly sand problem to a single dispersed shaly sand model to which the Waxman-Smits equation can be applied.

The total porosity of said formation, a fractional volume of the shale, and a resistivity of the shale are determined in a laminated reservoir including sands that may have dispersed shales therein. A tensor petrophysical model determines the laminar shale volume and laminar sand conductivity from vertical and horizontal conductivities derived from multi-component induction log data. NMR data are used to obtain measurements of the total clay-bound water in the formation and the clay bound water in shales in the formation.

Water saturation and sand fraction determination from borehole resistivity imaging tool, transverse induction logging and a tensorial dual water saturation model

Shoulder corrections are applied to measurements obtained from a multicomponent electromagnetic logging tool. An anisotropic resistivity model is obtained using the shoulder corrected data. The process is iterated until a good match is obtained between the shoulder corrected data and the model output.

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Rio de Janeiro, Brazil

Berthold Kriegshauser