Schlumberger Technology Corporation

Services Petroliers Schlumberger

Schlumberger Holdings Limited

Michael Thiel

Dzevat Omeragic

Tarek M Habashy

Andrei Davydychev

Yong-Hua Chen

Steven F Crary

Steve F Crary

Christophe Dupuis

Niloofar Farnoosh

Shabnam Ghadar

Andrei I Davydychev

Methods and systems for characterizing subterranean formations are described herein. One method includes performing electromagnetic logging measurements along a portion of a borehole traversing the subterranean formation using an electromagnetic logging tool to obtain electromagnetic data. The method also includes processing the electromagnetic data to determine a plurality of one dimensional formation models associated with the portion of the borehole. A two dimensional pixel grid is determined using the plurality of one dimensional formation models. The method further includes determining a two dimensional formation model for the subterranean formation by performing an inversion of the electromagnetic data using the two dimensional pixel grid. The methods and systems described herein can be used to steer a bottom-hole assembly during well placement.

Two dimensional pixel-based inversion

Inversion-based workflows are provided for real-time interpretation of the electromagnetic (EM) look-around and look-ahead measurements. The profile of a look-around zone is determined by interpreting EM measurements of a look-around zone. The profile of the look-around zone characterizes formation dip as well as vertical resistivity or resistivity anisotropy of one or more formation layers of the look-around zone. The profile of a look-ahead zone is determined by interpreting EM measurements of the look-ahead zone. The profile of the look-ahead zone characterizes formation dip as well as horizontal resistivity, vertical resistivity or anisotropy of one or more formation layers of the look-ahead zone. The workflows can also involve interpretation of look-around resistivity measurements to aid in the characterization of the look-around zone.

Methods and systems employing look-around and look-ahead inversion of downhole measurements

A method and system is provided for drilling a wellbore that traverses a geological formation using a drilling tool. The method and system derives a plurality of formation models that characterize the geological formation. The number of formation models represent layer structures with a heterogeneity (such a fault) offset laterally at variable distance relative to position of the drilling tool. Simulated directional resistivity data of the drilling tool is derived from the plurality of formation models. Certain simulated directional resistivity data are combined or selected for processing as multi-dimensional cross-plot data. Measured directional resistivity data obtained by the drilling tool is used to evaluate the multi-dimensional cross-plot data to determine distance of the heterogeneity relative to position of the drilling tool. The determined distance of the heterogeneity relative to position of the drilling tool can used for controlling drilling direction and can be stored in computer memory and used in other reservoir analysis.

Drilling with information characterizing lateral heterogeneities based on deep directional resistivity measurements

Methods for determining oil-water contact positions and water zone resistivities are provided. In one example, the method may involve performing a 1D inversion on data collected by a resistivity logging tool. Further, the method may involve scanning a resistivity profile of a reservoir generated by the 1D inversion for a boundary position below the resistivity logging tool. Furthermore, the method may involve applying a local residual weighted average on the boundary position to generate an initial estimation of an oil-water contact position and inverting the initial estimation of the oil-water contact to generate water zone resistivity and a modified oil-water contact position. Additionally, the method may involve running a smoothing local post-processing operation to generate a layered model and performing a 2D inversion on the layered model.

Workflow for navigation with respect to oil-water contact using deep directional resistivity measurements

An inversion based calibration method for downhole electromagnetic tools includes processing an inversion of a formation model using acquired electromagnetic measurement data to obtain formation parameters and calibration parameters for at least one measurement array.

Inversion-based calibration of downhole electromagnetic tools

A method is disclosed herein. The method includes disposing an electromagnetic logging tool in a borehole penetrating a formation, the electromagnetic logging tool being part of a drill string in the formation, the drill string having a drill bit. The method includes acquiring measurements using the electromagnetic logging tool. Further, the method includes using a processor, applying a pixel-based inversion to the acquired measurements to determine at least one formation property, wherein applying the pixel-based inversion includes using adaptive regularization.

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Cambridge, MA, United States of America

Michael Thiel