Abstract: A logging tool capable of making different types of measurements is provided, and a plurality of measurements on a formation are obtained. Certain mineral properties of the formation are assumed and a mixed properties theorem for the formation is invoked. Upper and lower velocity limits for sonic waves traveling through the formation are determined using the above information. Biot's constant is also computed using the above information. LWD data on the formation is obtained and an effective stress is determined. A total stress is determined and, from that and the other information, a pore pressure is determined.

Abstract: A technique includes identifying a fracture polygon intersecting a voxel of a three-dimensional grid of voxels representing a region of interest of a hydrocarbon-bearing reservoir based on data indicative of a discrete fracture network. The technique includes partitioning the polygon with a regular mesh of points and determining a number of the mesh points inside the voxel and inside the polygon. The technique includes estimating an area of the fracture inside the voxel based at least in part on the determined number of mesh points inside the voxel and inside the polygon. The technique includes determining at least one property of a portion of the hydrocarbon-bearing reservoir, which coincides with the voxel based at least in part on the estimated area of the fracture.

Abstract: A method for performing an oilfield operation at a wellsite having a drilling rig configured to advance a drilling tool into a subsurface formation. The method includes generating a borehole temperature model for an area of interest using water depth information and a vertical stress model, generating a formation temperature model using the borehole temperature model, generating a mud-weight pressure model using the formation temperature model and pressure coefficients, generating a formation pore pressure model using the mud-weight pressure model, and adjusting the oilfield operation based on the formation pore pressure model.

Abstract: A method and apparatus for estimating velocity in a subsurface region. Seismic data for a subsurface region may be received. One or more attributes for the seismic data may be calculated. A posterior distribution may be generated. The posterior distribution may represent one or more probabilities of one or more velocities for the attributes. A velocity with uncertainty may be determined for the subsurface region based on the posterior distribution. A pore pressure with uncertainty may be determined based on the velocity with uncertainty.

Abstract: A logging tool capable of making different types of measurements is provided, and a plurality of measurements on a formation are obtained. Certain mineral properties of the formation are assumed and a mixed properties theorem for the formation is invoked. Upper and lower velocity limits for sonic waves traveling through the formation are determined using the above information. Biot's constant is also computed using the above information. LWD data on the formation is obtained and an effective stress is determined. A total stress is determined and, from that and the other information, a pore pressure is determined.

Abstract: In general, in one aspect, the invention relates to a method for determining properties of a subterranean formation.

Abstract: A logging tool having a plurality of different sensor types having close spacings mounted on an articulated or extendible pad, a sleeve, a mandrel, a stabilizer, or some combination of those is provided and used to make measurements in a wellbore in a single logging run. Those measurements are used to create images of the wellbore and the images are used to deduce the local geology, optimize well placement, perform geomechanical investigation, optimize drilling operations, and perform formation evaluation. The logging tool includes a processor capable of making those measurements, creating those images, performing those operations, and making those determinations. The plurality of different sensors may be one or more resistivity sensors, dielectric sensors, acoustic sensors, ultrasonic sensors, caliper sensors, nuclear magnetic resonance sensors, natural spectral gamma ray sensors, spectroscopic sensors, cross-section capture sensors, and nuclear sensors, and they may be “plug-and-play” sensors.

Abstract: A method for performing an oilfield operation at a wellsite having a drilling rig configured to advance a drilling tool into a subsurface formation. The method includes generating a borehole temperature model for an area of interest using water depth information and a vertical stress model, generating a formation temperature model using the borehole temperature model, generating a mud-weight pressure model using the formation temperature model and pressure coefficients, generating a formation pore pressure model using the mud-weight pressure model, and adjusting the oilfield operation based on the formation pore pressure model.

Abstract: The invention relates to a method for determining maximum horizontal stress in an earth formation. The method includes obtaining fast shear wave velocities (Vs1) and slow shear wave velocities (Vs2) for various depths in the earth formation, calculating shear wave anisotropy (Adata) using Vs1 and Vs2, obtaining vertical stress (Sv) and minimum horizontal stress (Sh) for the formation, representing maximum horizontal stress (SH) using a parameterized function having at least one parameter and using Sh and Sv as input, determining a value of the at least one parameter by minimizing a cost function that represents a measure of difference between Adata and Apred for the various depths and Apred is predicted shear wave anisotropy determined using Sv, Sh, and SH, calculating SH using the parameterized function and the value of the at least one parameter, and storing SH in relation to the earth formation.

Abstract: A method for performing an oilfield operation at a wellsite having a drilling rig configured to advance a drilling tool into a subsurface formation. The method includes generating a borehole temperature model for an area of interest using water depth information and a vertical stress model, generating a formation temperature model using the borehole temperature model, generating a mud-weight pressure model using the formation temperature model and pressure coefficients, generating a formation pore pressure model using the mud-weight pressure model, and adjusting the oilfield operation based on the formation pore pressure model.

Abstract: A technique includes identifying a fracture polygon intersecting a voxel of a three-dimensional grid of voxels representing a region of interest of a hydrocarbon-bearing reservoir based on data indicative of a discrete fracture network. The technique includes partitioning the polygon with a regular mesh of points and determining a number of the mesh points inside the voxel and inside the polygon. The technique includes estimating an area of the fracture inside the voxel based at least in part on the determined number of mesh points inside the voxel and inside the polygon. The technique includes determining at least one property of a portion of the hydrocarbon-bearing reservoir, which coincides with the voxel based at least in part on the estimated area of the fracture.

Abstract: A method and apparatus for estimating velocity in a subsurface region. Seismic data for a subsurface region may be received. One or more attributes for the seismic data may be calculated. A posterior distribution may be generated. The posterior distribution may represent one or more probabilities of one or more velocities for the attributes. A velocity with uncertainty may be determined for the subsurface region based on the posterior distribution. A pore pressure with uncertainty may be determined based on the velocity with uncertainty.

Abstract: Predicting sand production in a wellbore. A first set of characteristics is determined for a formation in the wellbore, wherein determining uses a plastic model of the formation, and wherein the first set of characteristics comprises a yield surface, a failure surface, a stress total strain, an elastic strain, and a plastic-strain relationship. A relationship among a second set of characteristics of the wellbore is determined using an effective stress model, wherein the second set comprises a drawdown pressure, a production rate, pore pressure, a temperature and a viscosity of a fluid in the wellbore, a fluid flow pressure in the wellbore, a drag force of fluid flow in the wellbore, and a type of fluid flow in the wellbore. A critical total strain is determined for the formation using the first set of characteristics and the relationship. The critical total strain is calibrated using a thick wall test.

Abstract: In general, in one aspect, the invention relates to a method for determining properties of a subterranean formation.

Abstract: The invention relates to a method for determining maximum horizontal stress in an earth formation. The method includes obtaining fast shear wave velocities (Vs1) and slow shear wave velocities (Vs2) for various depths in the earth formation, calculating shear wave anisotropy (Adata) using Vs1 and Vs2, obtaining vertical stress (Sv) and minimum horizontal stress (Sh) for the formation, representing maximum horizontal stress (SH) using a parameterized function having at least one parameter and using Sh and Sv as input, determining a value of the at least one parameter by minimizing a cost function that represents a measure of difference between Adata and Apred for the various depths and Apred is predicted shear wave anisotropy determined using Sv, Sh, and SH, calculating SH using the parameterized function and the value of the at least one parameter, and storing SH in relation to the earth formation.

Abstract: Predicting sand production in a wellbore. A first set of characteristics is determined for a formation in the wellbore, wherein determining uses a plastic model of the formation, and wherein the first set of characteristics comprises a yield surface, a failure surface, a stress total strain, an elastic strain, and a plastic-strain relationship. A relationship among a second set of characteristics of the wellbore is determined using an effective stress model, wherein the second set comprises a drawdown pressure, a production rate, pore pressure, a temperature and a viscosity of a fluid in the wellbore, a fluid flow pressure in the wellbore, a drag force of fluid flow in the wellbore, and a type of fluid flow in the wellbore. A critical total strain is determined for the formation using the first set of characteristics and the relationship. The critical total strain is calibrated using a thick wall test.

Abstract: A method for performing an oilfield operation at a wellsite having a drilling rig configured to advance a drilling tool into a subsurface formation. The method includes generating a borehole temperature model for an area of interest using water depth information and a vertical stress model, generating a formation temperature model using the borehole temperature model, generating a mud-weight pressure model using the formation temperature model and pressure coefficients, generating a formation pore pressure model using the mud-weight pressure model, and adjusting the oilfield operation based on the formation pore pressure model.

Abstract: A method for determining properties of a transverse isotropic region of earth formations traversed by a wellbore having substantially vertical and deviated sections therethrough, including measuring sonic velocity properties in formations surrounding the substantially vertical section of the wellbore; measuring sonic velocity properties in formations surrounding the deviated section of the wellbore; and determining, from the measured velocities, all of the transverse isotropic elastic constants of the region.

Abstract: A method for determining properties of a transverse isotropic region of earth formations traversed by a wellbore having substantially vertical and deviated sections therethrough, including measuring sonic velocity properties in formations surrounding the substantially vertical section of the wellbore; measuring sonic velocity properties in formations surrounding the deviated section of the wellbore; and determining, from the measured velocities, all of the transverse isotropic elastic constants of the region.