EQUINOR ENERGY AS

A method of estimating the primary and secondary acoustic velocities, Vp and Vs, of formation surrounding a first wellbore includes obtaining well logging data for a multiplicity of other wellbores to collect, for each other wellbore a plurality of input data sets including at least a Nuclear Magnetic Resonance logging data set, and an element composition scanning data set. The operation further collects, for each other wellbore, at least one output data set including a primary and secondary velocity data set. The method incudes training or establishing at least one regression model using said input and output data sets, obtaining well logging data for said first wellbore to obtain a corresponding plurality of input data sets, and applying the obtained corresponding plurality of input data sets to the trained or established regression model to generate as an output of the regression model, an output data set for the first wellbore including a primary and secondary velocity data set.

A method of obtaining a three-dimensional model of a current sub-surface formation. The method comprises obtaining three-dimensional, treated, physical survey data, and comprising measurement data at each of a multiplicity of indexed locations within a regular three-dimensional grid of indexed locations. For a given set of geological processes, a backward sequence of corresponding inverse geological processes is obtained which, when the backward sequence is applied to the treated physical survey data, transform that treated physical survey data into representative survey data which is approximately representative of the sub-surface formation at a time of its formation. A three-dimensional model of the sub-surface formation is derived at a time of its formation, the model comprising one or more material properties at each of said indexed locations, and said set of geological processes is applied to the derived three-dimensional model, in a forward sequence to obtain a current model of the sub-surface formation. Each of the geological processes and their inverses is defined as a linear or rotational shift, or combination of such shifts, of the measurement data or material properties between the indexed locations.

A method of analysing seismic data from a geological structure. The method includes determining a set of tiles from a data cube of seismic data and determining which tiles of the set of tiles can be grouped into one or more patches of tiles.

A method of estimating a position of a well path within a subsurface formation of the Earth includes determining a well path estimate using navigation measurements from a downhole tool and a position estimate derived from seismic data. A method of geosteering includes estimating a position of the well path and controlling a drill bit in response to the estimated position of the well path to follow a desired well trajectory.

A method of obtaining a model of a sub-surface region, the model comprising a three dimensional matrix of sub-surface material property values. The method comprises providing a first approximation of said model, and performing simulations using the model to generate (i) a reference upgoing energy wave data set d 0 , where the acquisition parameters used in the simulation are a set of known acquisition parameters, and (ii) a plurality of perturbed upgoing energy wave data sets d 0 where the acquisition parameters are obtained by randomly perturbing said set of known acquisition parameters. The method further comprises forming a matrix D, the columns of which are the differences d i −d 0 between the ith perturbed data set and the reference data set, applying an analysis to the matrix D to describe the matrix using a set of vectors, and selecting the most important vectors from said set of vectors to obtain a subset of vectors that describe said matrix D to an approximation. An iterative procedure is performed to improve said first approximation of said model, or a further approximation model, wherein, at each step of the procedure, a model update Δm is determined, the model update being that model update that minimises a measure of the data misfit between said upgoing energy wave data set d rec and a data set simulated using the updated model, said measure using said subset of vectors to account for uncertainty in the upgoing energy wave data set d rec .

A method of analysing seismic data to detect possible hydrocarbons includes determining a set of data tiles from a seismic data cube of seismic data and testing each data tile in the set of data tiles to determine whether it corresponds to a possible fluid contact.

A method of estimating the primary and secondary acoustic velocities, Vp and Vs, of formation surrounding a first wellbore includes obtaining well logging data for a multiplicity of other wellbores to collect, for each other wellbore a plurality of input data sets including at least a Nuclear Magnetic Resonance logging data set, and an element composition scanning data set. The operation further collects, for each other wellbore, at least one output data set including a primary and secondary velocity data set. The method incudes training or establishing at least one regression model using said input and output data sets, obtaining well logging data for said first wellbore to obtain a corresponding plurality of input data sets, and applying the obtained corresponding plurality of input data sets to the trained or established regression model to generate as an output of the regression model, an output data set for the first wellbore including a primary and secondary velocity data set.

A method of calculating the temperature and/or porosity of a geological structure, wherein there is provided at least two geophysical parameters of the geological structure, the method including inverting the at least two geophysical parameters to estimate the temperature and/or porosity of the geological structure.

A method of estimating a position of a well path within a subsurface formation of the Earth, the method comprising determining a well path estimate using navigation measurements from a downhole tool and a position estimate derived from seismic data. A method of geosteering comprising: estimating a position of the well path and controlling a drill bit in response to the estimated position of the well path to follow a desired well trajectory.

A method of calculating the temperature of a geological structure is disclosed, wherein there is provided a magnetic parameter of the geological structure. The method includes inverting the magnetic parameter to estimate the temperature of the geological structure.