Abstract: A method for providing a calibrated rock-physics model of a subsoil. First, a geological model of the subsoil comprising a grid made of cells, associated with a rock-physics parameter is obtained. A group of cells forming a calibration body is selected in the grid. The calibration body corresponds to a region of the subsoil having substantially homogenous rock-physics parameter values. Finally, an adjustable constant parameter in a physical equation expressing a relationship between the petro-physical parameter and a petro-elastic parameter in the calibration body is calibrated so as to reduce a mismatch between the petro-elastic parameter estimated using the physical equation and a petro-elastic parameter value determined from inverted seismic data, the calibrated physical equation providing a calibrated rock-physics model of the subsoil in the calibration body.

Abstract: 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.

Abstract: The invention notably relates to a computer-implemented method of geological grid analysis, for hydrocarbon production, based on values of a geological attribute in a subsoil. The method comprises providing one or more geological grids. Each geological grid represents the subsoil. Each geological grid comprises respective cells. Each cell represents a respective portion of the subsoil. The method further comprises, for each geological grid, providing a first distribution. The first distribution comprises geological attribute values each on a respective cell. Each geological attribute value represents a value of the geological attribute in the respective portion. The method further comprises, for each geological grid, determining a second distribution based on the first distribution. The second distribution comprises flux values each on a respective cell. Each flux value represents a flux of the geological attribute in the respective portion. This constitutes an improved method of geological grid analysis.

Abstract: It is proposed a method which comprises providing a geomechanical model of the geological environment, measurements of a first geological attribute each performed at a respective first position of the geological environment, constraints on a second geological attribute related to a yield criterion and each assigned to a respective second position of the geological environment, and a geomechanical simulator. The method also comprises determining the stress field derivable from the data outputted by the geomechanical simulator taking as input the geomechanical model and an optimal set of one or more boundary conditions. This provides an improved solution for estimating in situ stress field of a geological environment.

Abstract: The present disclosure concerns a computer implemented method for correcting a reservoir model comprising a stratigraphic grid modeling a reservoir geological formation. The method includes obtaining a 3D image representing values of a physical property obtained from seismic measurements performed on the reservoir geological formation. A skeleton is calculated for the values of the physical property of the 3D image. Each point of the skeleton is associated to a respective cell of the stratigraphic grid. One reference layer is determined for at least one set of points of the skeleton. For each point of the at least one set, a layer gap is calculated between the reference layer and the cell associated to said point, and the reservoir model is corrected based on the layer gaps.

Abstract: 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.

Abstract: A method includes obtaining a first time series of a first well parameter from the first well and a second time series of a second well parameter from the second well, processing the first time series to obtain a processed first time series, filtering the second time series by removing dynamic variations from the second time series to obtain a filtered second time series representative of static variations of the second time series, and determining a correlation between the processed first time series and the filtered second time series at various time shifts between the processed first time series and the filtered second time series, and determining a maximal correlation coefficient and a time shift at maximal correlation between the processed first time series and the filtered second time series, the maximal correlation coefficient being representative of the connectivity between the first well and the second well.

Abstract: A subsoil region is represented using a grid having columns of cells arranged in an array of horizontal positions. The cells of a column are delineated by geological layering of the subsoil region. The method, used for estimating elastic parameters in the subsoil region, comprises obtaining seismic traces and performing seismic inversion for the columns of cells. The seismic inversion for a column comprises selecting a set of elastic parameter values that minimizes a cost function regardless of statistical distribution of the elastic parameter values. The set of elastic parameter values is selected among a plurality of candidate sets of elastic parameter values each having values of elastic parameters for the cells of the column.

Abstract: Disclosed is a method of characterizing a subsurface volume. The method comprises: extracting a geobody from seismic data arranged within a discretized volume comprising a plurality of cells, the geobody comprising a subset of the plurality of cells, each cell of the subset having one or more properties indicative of a particular fluid phase. The extraction of the geobody comprises: determining a propagation probability value for each cell indicative of the probability that a front will propagate through the cell; beginning from a source within the discretized volume, using the propagation probability value to calculate a traveltime for each cell, the travel time describing the time the front takes to travel from the source point to the cell; and using the traveltimes to extract the geobody from the seismic data.

Abstract: A method comprises obtaining a first time series of a first well parameter from the first well and a second time series of a second well parameter from the second well, processing the first time series to obtain a processed first time series, filtering the second time series by removing dynamic variations from the second time series to obtain a filtered second time series representative of static variations of the second time series, and determining a correlation between said processed first time series and said filtered second time series at various time shifts between said processed first time series and said filtered second time series, and determining a maximal correlation coefficient and a time shift at maximal correlation between said processed first time series and said filtered second time series, the maximal correlation coefficient being representative of the connectivity between the first well and the second well.

Abstract: It is proposed a method which comprises providing a geomechanical model of the geological environment, measurements of a first geological attribute each performed at a respective first position of the geological environment, constraints on a second geological attribute related to a yield criterion and each assigned to a respective second position of the geological environment, and a geomechanical simulator. The method also comprises determining the stress field derivable from the data outputted by the geomechanical simulator taking as input the geomechanical model and an optimal set of one or more boundary conditions. This provides an improved solution for estimating in situ stress field of a geological environment.

Abstract: A method for providing a calibrated rock-physics model of a subsoil. First, a geological model of the subsoil comprising a grid made of cells, associated with a rock-physics parameter is obtained. A group of cells forming a calibration body is selected in the grid. The calibration body corresponds to a region of the subsoil having substantially homogenous rock-physics parameter values. Finally, an adjustable constant parameter in a physical equation expressing a relationship between the petro-physical parameter and a petro-elastic parameter in the calibration body is calibrated so as to reduce a mismatch between the petro-elastic parameter estimated using the physical equation and a petro-elastic parameter value determined from inverted seismic data, the calibrated physical equation providing a calibrated rock-physics model of the subsoil in the calibration body.

Abstract: A subsoil region is represented using a grid having columns of cells arranged in an array of horizontal positions. The cells of a column are delineated by geological layering of the subsoil region. The method, used for estimating elastic parameters in the subsoil region, comprises obtaining seismic traces and performing seismic inversion for the columns of cells. The seismic inversion for a column comprises selecting a set of elastic parameter values that minimizes a cost function regardless of statistical distribution of the elastic parameter values. The set of elastic parameter values is selected among a plurality of candidate sets of elastic parameter values each having values of elastic parameters for the cells of the column.

Abstract: A 4D seismic technique, where a base seismic trace is measured at a first time in a region of the subsoil, and then a monitor seismic trace corresponding to the base seismic trace is measured at a second time. To interpret the 4D measurements, assumptions are made about the variation of elastic parameters in permeable layers at predefined positions in one direction between the first and the second time. Elastic parameters include the density (?) and the speed of propagation of the pressure waves (VP) in the permeable layers. Numerical evaluation is performed for a capability of each assumption about the variation of elastic parameters to give an account of a change between the measured base seismic trace and the measured monitor seismic trace, and the variation of the elastic parameters is estimated in accordance with an assumption of optimum capability.

Abstract: According to the invention, elastic parameters, including density, pressure wave propagation speed, and/or shear in pervious layers located in a dense underground area along an array of horizontal positions, are estimated by inverting 4D seismic data. Firstly, an estimate of variations in the elastic parameters in one or more starting positions of the array, which can be located on bored wells within the area in question, is obtained. Then, a propagation algorithm is used in order to gradually carry out the 4D data inversion on the basis of the starting positions. The inversion takes into account the previously estimated parameter variations. A spatial variation in the depth and/or the thickness of the pervious lavers in question can also be taken into account. Propagation is based on positions that are consecutively selected as providing optimal values for a cost function assessed in order to invert the 4D data.

Abstract: According to the invention, elastic parameters, including density, pressure wave propagation speed, and/or shear in pervious layers located in a dense underground area along an array of horizontal positions, are estimated by inverting 4D seismic data. Firstly, an estimate of variations in the elastic parameters in one or more starting positions of the array, which can be located on bored wells within the area in question, is obtained. Then, a propagation algorithm is used in order to gradually carry out the 4D data inversion on the basis of the starting positions. The inversion takes into account the previously estimated parameter variations. A spatial variation in the depth and/or the thickness of the pervious lavers in question can also be taken into account. Propagation is based on positions that are consecutively selected as providing optimal values for a cost function assessed in order to invert the 4D data.

Abstract: A 4D seismic technique, where a base seismic trace is measured at a first time in a region of the subsoil, and then a monitor seismic trace corresponding to the base seismic trace is measured at a second time. To interpret the 4D measurements, assumptions are made about the variation of elastic parameters in permeable layers at predefined positions in one direction between the first and the second time. Elastic parameters include the density (?) and the speed of propagation of the pressure waves (VP) in the permeable layers. Numerical evaluation is performed for a capability of each assumption about the variation of elastic parameters to give an account of a change between the measured base seismic trace and the measured monitor seismic trace, and the variation of the elastic parameters is estimated in accordance with an assumption of optimum capability.

Abstract: Three seismic waves are emitted from different emission points situated outside the well that is to be positioned relative to a seismic image. The times of arrival of these seismic waves are measured on a detector placed in the well. The propagation of the seismic waves emitted from the respective emission points is simulated using a speed model that has been used to construct the seismic image. The simulation provides the respective wavefronts presented by each of the waves at the end of a time equal to the time of arrival measured on the detector for this wave. The detector can then be positioned in the envelope area of the wavefronts, adjacent to the intersection of the wavefronts estimated in the seismic volume.

Abstract: A process for calculating a meshed description of a realization of an oil-bearing reservoir takes as its starting point a reference realization of the reservoir with a plurality of stratigraphic surfaces, a meshed reference description for the reference realization comprising a plurality of planes some of which describe the stratigraphic surfaces, each plane comprising a plurality of points, at least two stratigraphic surfaces of the realization corresponding to two stratigraphic surfaces of the reference realization. A plane of the meshed description representing one of the two stratigraphic surfaces of the realization is obtained by applying displacements to the points of the planes of the reference description, making it possible to pass from the reference stratigraphic surface to the stratigraphic surface in the realization. The other planes of the description are obtained thereafter by interpolation.

Abstract: A process for calculating a meshed description of a realization of an oil-bearing reservoir takes as its starting point a reference realization of the reservoir with a plurality of stratigraphic surfaces, a meshed reference description for the reference realization comprising a plurality of planes some of which describe the stratigraphic surfaces, each plane comprising a plurality of points, at least two stratigraphic surfaces of the realization corresponding to two stratigraphic surfaces of the reference realization. A plane of the meshed description representing one of the two stratigraphic surfaces of the realization is obtained by applying displacements to the points of the planes of the reference description, making it possible to pass from the reference stratigraphic surface to the stratigraphic surface in the realization. The other planes of the description are obtained thereafter by interpolation.