A fracture simulation system is provided to determine anisotropic effective permeability of rock formations having natural fractures therein.

A method for determining an intersection between a polygon representing a boundary of a surface in an earth formation and a plane includes: receiving a polygon representing a boundary of a surface in an earth formation, the polygon having a series of straight segments with a point at each end of each of the segments; overlaying a cutting grid having grid planes over the polygon; identifying a specific pattern of two adjacent segments in the polygon by proceeding from a first segment to a second segment in a selected rotational direction; matching the specific pattern to a reference pattern; categorizing the point between the two adjacent segments as an intersection point or as a non-intersection point based on the reference pattern; the iterating the identifying, matching, and categorizing for each pair of adjacent segments in the polygon such that each point between adjacent segments in the polygon is categorized.

A method for estimating a fluid pressure required to stimulate a subsurface formation includes using seismic signals detected by a plurality of seismic sensors disposed proximate the subsurface formation. Spatial positions and times of origin (“hypocenters”) of each of a plurality of microseismic events induced by pumping fluid into the subsurface formation are estimated. Magnitudes and directions of principal stresses are estimated from the hypocenters and from amplitude and phase of the detected seismic signals for each of the microseismic events. Shear and normal stresses of induced fractures are from the estimated principal stresses. A fluid pressure required to cause formation failure on each fracture is estimated using the estimated shear and normal stresses.

An exploration method starts from cuttings associated with sampling intervals and well data for a well in a subsurface formation. The cuttings are prepared and analyzed to extract textural and chemical/mineralogical data for plural fragments in each sample that is made of the cuttings in one sampling interval. The method then includes matching lithotypes of rock defined according to the textural and chemical/mineralogical data for each fragment with segments of the well data in the corresponding sampling interval to obtain correspondences between the lithotypes and depth ranges. The correspondences between the lithotypes and the depth ranges may be used as constraints for seismic data inversion.

A computer implemented method for analyzing a reservoir grid modeling a reservoir geological formation is provided in which the reservoir grid corresponds to a 3D grid of cells associated to respective values of at least one geological property. The method includes obtaining a 4D seismic image of the reservoir geological formation. A skeleton of the 4D seismic image is calculated, and the skeleton extends between at least one origin and a plurality of extremities. Each point of the skeleton is associated to a value of the at least one geological property of the reservoir grid. Flow time values are calculated for a fluid flowing from the origin to the extremities along the skeleton, based on the at least one geological property values associated to the points of the skeleton. The reservoir grid is calculated based on the flow time values.

Partially coupling a geomechanical simulation with a reservoir simulation facilitates predicting strain behavior for a reservoir from production and injection processes. A method comprises generating a geomechanical model based on a mechanical earth model that represents a subsurface area. The geomechanical model indicates a division of the mechanical earth model into a plurality of grid cells that each correspond to a different volume of the subsurface area. Based on a first virtual compaction experiment with the geomechanical model, compaction curves are generated. The compaction curves represent porosity as a function of stress. The compaction curves are converted from porosity as a function of stress to porosity as a function of pore pressure. The geomechanical model is partially coupled to a reservoir simulation model using the converted compaction curves.

The invention relates to a method for upscaling data of a reservoir model, the method being implemented by a computer, and comprising the steps of: —defining a reservoir model comprising a volume of dimensions D.sub.H, D.sub.v along respectively two distinct directions H,V, —receiving statistical data relative to the volume, comprising: relative proportions of at least two rock types, wherein each rock type corresponds to a permeability value and respective curves of relative permeability with water saturation of two phases of a fluid within the rock type, one of the phases being water, and a variogram of absolute permeability defined by correlation lengths L.sub.H, L.sub.v, along the two directions H,V, and, —computing, equivalent relative permeability values of a phase of the fluid within the volume, comprising: at least an equivalent relative permeability value according to the first direction H, and at least an equivalent relative permeability value according to the second direction V, wherein each equivalent relative permeability value of a phase of the fluid according to a direction d chosen among H,V is computed based on relative permeability values of the phase of the fluid within each rock type, and on a coefficient depending on the anisotropy of the volume and on non-ergodicity parameters ε.sub.H, ε.sub.v relative to each direction H,V, the non-ergodicity parameters depending on the volume dimensions along said directions and on the variogram of absolute permeability.

Systems and methods for assessing seismic risk. The system and methods disclose deriving a model that is used to assess seismic risk of operations at a given location. A first location is identified for which at least one training seismic risk value is known from independent sources. A plurality of training input parameters associated with the first location is received. The at least one training seismic risk value is received. A process model is derived that relates the plurality of training input parameters to the at least one training seismic risk value by determining influence values of the training input parameters. A second location is identified for which a seismic risk is to be determined. A plurality of working input parameters associated with the second location is received. The process model is applied to the plurality of working input parameters to determine a seismic risk value at the second location.

A system for estimating a property of a region of interest includes an acoustic measurement device including a transmitter configured to emit an acoustic signal having at least one selected frequency configured to penetrate a surface of a borehole in an earth formation and produce internal diffuse backscatter from earth formation material behind the surface and within the region of interest, and a receiver configured to detect return signals from the region of interest and generate return signal data. The system also includes a processing device configured to receive the return signal data, process the return signal data to identify internal diffuse backscatter data indicative of the internal diffuse backscatter, calculate one or more characteristics of the internal diffuse backscatter, and estimate a property of the region of interest based on the one or more characteristics of the internal diffuse backscatter.

A method of simulating a process of a geological structure includes obtaining a first digital model including structural data representing a geological structure. The method also includes selecting at least one marching technique based in part on a grid dimension and a grid cell shape of a grid on the first digital model. The method further includes applying the at least one marching technique to at least a portion of the structural data of the first digital model to identify at least some boundary data. The method further includes populating a second digital model based in part on the first digital model, a property, and the boundary data. The method further includes simulating a process of the geological structure using the second digital model.