Baker Hughes Corporation

Liming Yu

Otto N Fanini

Berthold Kriegshauser

Stanislav W Forgang

Gulamabbas A Merchant

Berthold Kriegshäuser

Tsili Wang

Leonty Abraham Tabarovsky

Jiaqi Xiao

Pravin Gupta

Michael Rabinovich

Sheng Fang

Xiao Ming Tang

Zhiyi Zhang

Jack Signorelli

Richard A Mollison

Berthold Kriegsh&auml;user

Steve McWilliams

Multi-component induction measurements are made using a resistivity logging tool in an anistropic earth formation. A subset of the multi-component measurements are inverted to first determine horizontal resistivities. Using the determined horizontal resistivities and another subset of the multi-component measurements, the vertical resistivities are obtained. Results of using the in-phase signals are comparable to those obtained using multifrequency focusing of quadrature signals.

Method and apparatus for use of the real component of a magnetic field of multicomponent resistivity measurements

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

Neural networks may be used to determine and predict formation dip angles and perform quality assurance assessments from data collected with a multi-component induction tool used for well logging. The neural networks make use of corrected, rotated and normalized data to provide the predictions and assessments. Synthetic data using various models is used to train the neural networks. The teachings herein provide for real-time determinations with a substantial degree of accuracy in the results.

Real time data quality control and determination of formation angles from multicomponent induction measurements using neural networks

Cross-component measurements made with a dual-transmitter configuration are processed to estimate a distance to an interface in an anisotropic earth formation. Optionally, measurements may be made with two receivers, also in the dual transmitter configuration.

Elimination of the anisotropy effect in LWD azimuthal resistivity tool data

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

A method is discussed for obtaining resistivity values in a horizontal or highly-deviated wellbore penetrating an anisotropic formation layer. Multi-component data is obtained from the formation layer. An initial value of horizontal and vertical resistivity can be determined by using a whole space model and assuming an isotropic layer. Revised values of the vertical and horizontal resistivities are obtained through a first and second inversion process. A first inversion is performed on the horizontal resistivity, holding a value of vertical resistivity constant. A second inversion is performed on the vertical resistivity, holding a value of horizontal resistivity constant. These inversions are iterated until a desired convergence is achieved.

Real time processing of multicomponent induction tool data in highly deviated and horizontal 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

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

Measurements made by a multicomponent logging tool in a borehole are inverted to obtain horizontal and vertical resistivities of a formation traversed by the borehole. The model includes layers of equal thickness, each layer having a horizontal resistivity and a vertical resistivity. For a vertical borehole, the inversion is done by first iteratively obtaining the horizontal resistivities of the layer using the H component of the data wherein in successive steps of the iteration, the horizontal resistivity for each layer is multiplied by a ratio of a model H output to the measured H . The vertical resistivity model is set equal to the derived horizontal resistivities and the iterative process is repeated using the ratio of the model H output to the measured H . A similar process is used for boreholes with a known inclination. For such an inclined borehole, the two horizontal components H and H are summed to give a horizontal measurement H that is independent of tool rotation. The first step uses a ratio of the model H output to the measured H data to obtain an apparent resistivity, and, in the second step, the ratio of the model H output and the measured H data are used along with a known relationship between the apparent resistivity and the horizontal and vertical resistivities in an iterative manner. No Jacobians or gradients are necessary in the method, so that computational times are small relative to prior art gradient methods.

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Stafford, TX, United States of America

Liming Yu