Schlumberger Technology Corporation

Services Petroliers Schlumberger

Geoquest Systems B.v.

John Adam Donald

Takeshi Endo

Henri-Pierre Valero

Tom R Bratton

Vincenzo De Gennaro

Erik Wielemaker

GongRui Yan

Saad Kisra

Claude Signer

Jeroen Jocker

Haitao Sun

Peter Kaufman

Romain C A Prioul

Sachin Bammi

Randolph Koepsell

Mitsuko Kitazawa

Alexander Ramirez

Xinyu Liang

Francisco Gomez

Cheolkyun Jeong

Boxian Jing

Florian Karpfinger

A method, apparatus, and program product estimate anisotropic properties of an anisotropic formation based at least in part on determinations of a deviation of a wellbore associated with the anisotropic formation and an availability of non-sonic measurement data associated with the anisotropic formation. The determinations are used in the selection of at least one computer-implemented model that in turn may be applied to determine one or more unknown elastic constants for an elastic stiffness matrix.

Workflow for determining stresses and/or mechanical properties in anisotropic formations

A method, apparatus, and program product model stress characteristics of a subsurface formation based at least in part on acoustic data and image data associated with the subsurface formation. The acoustic data is analyzed to determine acoustic based stress values, and the image data is analyzed to determine image based stress values. The acoustic based stress values and the image based stress values are integrated to generate an integrated stress profile that includes one or more modeled stress characteristics of the subsurface volume.

Subsurface formation modeling with integrated stress profiles

A method for estimating formation slowness is provided. The method comprises forward modeling to compute formation slownesses based on a first method for orthorhombic media using stress magnitudes and third-order elastic constants as inputs, and forward modeling to determine formation slownesses analytically based on a second method using stress magnitudes, stress azimuth and third-order elastic constants as inputs. The first method may be based on Tsvankin method and the second method may be based on Christoffel method. The forward modeling may further use well configuration and reference moduli as inputs, and the results from the forward modeling may include formation slownesses, and at least one of vertical slownesses, anisotropic parameters, anellipticity indicators and fast shear azimuth. The method may further comprise assessing quality of the forward modeling based on results output from the forward modeling.

Method and system for estimating formation slowness

Systems and methods for differential energy analysis of dipole acoustic signals to facilitate identification of geological or borehole characteristics are provided. An acoustic downhole tool may be placed into a borehole in a geological formation. A dipole acoustic signal may be emitted using one or more acoustic transmitters of the downhole tool, and the dipole acoustic signal may be measured using one or more acoustic receivers of the downhole tool. Using a processor, a dipole differential energy of the dipole acoustic signal (as measured by two of the one or more acoustic receivers or as emitted by two of the one or more acoustic transmitters, or both) may be computed. The processor may provide an indication of the dipole differential energy to facilitate identification of characteristics of the geological formation or the borehole, or both.

Differential energy analysis for dipole acoustic measurement

Fracture- and stress-induced sonic anisotropy is distinguished using a combination of image and sonic logs. Borehole image and sonic logs are acquired via known techniques. Analysis of sonic data from monopole P- and S-waves, monopole Stoneley and cross-dipole shear sonic data in an anisotropic formation are used to estimate at least one compressional and two shear moduli, and the dipole fast shear direction. Fracture analysis of image logs enables determination of fracture types and geometrical properties. Geological and geomechanical analysis from image logs provide a priori discrimination of natural fractures and stress-induced fractures. A forward quantitative model of natural fracture- and stress-induced sonic anisotropy based on the knowledge of fracture properties interpreted from image logs allows the computation of the fast-shear azimuth and the difference in slowness between the fast- and slow-shear. The misfit between predicted and observed sonic measurements (i.e. fast-shear azimuth and slownesses) is then optimized in order to discriminate depth zones with an elastic medium as being influenced by the presence of open natural fractures, closed natural fractures and fractures induced by non-equal principal stress effects.

Discriminating natural fracture- and stress-induced sonic anisotropy using a combination of image and sonic logs

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Clamart, France

John Adam Donald