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Totalenergies Onetech

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Totalenergies Se

Thomas David Blanchard

Jonathan Anthony Edgar

Pierre Daniel Thore

Christian Hubans

Constantin Vili Gerea

Disclosed is a method and associated computer program and apparatus for characterising changes within a subsurface volume between a first time and a second time. The method comprises obtaining first seismic data corresponding to the first time and processing this data to obtain a seismic image of the subsurface volume. This processing is reversed for relevant portions of the seismic image to obtain relevant portions of first seismic data. Changes within the subsurface volume between the first time and the second time are characterised by estimating the changes between second seismic data corresponding to the second time and the relevant portions of first seismic data.

Method for obtaining estimates of a model parameter so as to characterise the evolution of a subsurface volume over a time period using time-lapse seismic

Disclosed is a method for characterizing the evolution of a reservoir by determining a seismic wavelet which links observed seismic data to a sequence of reflectivities. The method comprises obtaining seismic data () representing seismic changes which have occurred between a first time and a second time, said seismic data comprising a plurality of seismic traces; and performing an optimization operation simultaneously () on the seismic traces so as to optimize for said seismic wavelet. The optimization operation may be performed without using known reflectivity data as an input.

Process for characterising the evolution of an oil or gas reservoir over time

Abstract Disclosed is a method for characterizing the evolution of a subsurface volume over time. The method comprises providing first and second surveys of the subsurface volume. Each survey comprises seismic data acquired by transmitting seismic signals into the subsurface volume and subsequently detecting some or all of the seismic signals after reflection within the subsurface. The first seismic data of the first survey corresponds to a first time and the second seismic data of the second survey corresponds to a second time. At least some of the first seismic data and the second seismic data is obtained with a non-zero offset. An inversion is performed to obtain estimates of changes having occurred between the first time and the second time in terms of at least one model parameter; wherein for the inversion: the first seismic data and the second seismic data is not processed to be equivalent to zero-offset data prior to the inversion; and it is assumed that the path taken by each received seismic signal between its transmission and reception is the same for the first survey and the second survey.

Method for obtaining estimates of a model parameter so as to characterise the evolution of a subsurface volume over a time period

Disclosed is a method a seismic inversion for petrophysical properties of a subsurface volume comprising the steps of: obtaining petrophysical data relating to valid geological and/or dynamical scenarios, converting this data into valid combinations of elastic parameters; projecting the valid combinations of elastic parameters onto a spherical plot; and determining a penalty term from the distances between each cell of the spherical plot and the nearest valid combination of elastic parameters within the subsurface volume. Valid geological and/or dynamical scenarios comprise those which are petrophysically possible. The penalty term is then used to constrain an inversion minimizing a cost function associated with seismic mismatch between two or more seismic surveys.

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Aberdeen, United Kingdom

Thomas David Blanchard