Method of simulating the sedimentary deposition in a basin respecting the thicknesses of the sedimentary sequences

• US 20060015260A1
• Filed: 06/24/2005
• Published: 01/19/2006
• Est. Priority Date: 06/30/2004
• Status: Active Grant

• Current Assignee: Institut Francais Du Petrole
• Original Assignee: Institut Francais Du Petrole
• Inventors: Cacas, Marie-Christine, Dobranszky, Gabriela, Masson, Roland
• Granted Patent: US 7,337,069 B2
• Time in Patent Office: Days
• US Class Current: 702/14
• CPC Class Codes: G01V 1/282 Application of seismic models, synthetic seismograms
• CPC Class Codes: G01V 11/00 Prospecting or detecting by methods combining techniques covered by two or more of main groups G01V1/00 - G01V9/00
• CPC Class Codes: G01V 2210/661 Model from sedimentation process modeling, e.g. from first principles

Abstract

The method allows, by means of an iterative inversion algorithm, to predict the spatial distribution of the lithologic composition of sediments deposited in a sedimentary basin during a geologic time interval, and the temporal evolution of the depositional profile throughout filling of the basin, while respecting exactly the thicknesses of the sedimentary sequences measured otherwise. The input data consist of the thickness maps of the sedimentary layer studied, data relative to the location and to the composition of the sediment supply at the boundaries of the sedimentary basin studied, and physical parameters characterizing transport of the sediments during the period considered. These data are determined by interpretation of seismic surveys, by measurements and observations. This set of data is applied to an iterative inversion loop initialized by the accommodation provided by a stationary multilithologic diffusive model. This loop then works as a fixed-point algorithm correcting the accommodations by means of a preconditioning of the residue on the sequence thicknesses obtained by an instationary model. This preconditioning is obtained by applying the tangent application of the stationary multilithologic model to the residue on the thicknesses. At the output, we obtain the accommodation at the end of the sequence considered, as well as the bathymetry and surface composition solutions at any time of the sequences of the instationary model calibrated to the layer thicknesses. Application: location of hydrocarbon reservoirs notably.

Claims

1. A method for forming a model of a spatial distribution of a lithologic composition of sediments deposited in a sedimentary basin having sedimentary sequences, and a temporal evolution of bathymetry, comprising:

estimating, from interpretations of measurements resulting from seismic surveys and well data, input data comprising

maps giving the current thicknesses of the sedimentary sequences,

a map of the initial topography of the basement of the sedimentary basin,

a distribution of the sedimentary supply in the basin, comprising at least the following descriptions of location in space, lithologic composition, and evolution of supply volume in time during filling of the basin, and

diffusion coefficient values characterizing the transport of the sediments to the basin,

applying the input data to an iterative inversion procedure, wherein the thicknesses of each of the sequences are calculated by solving in stationary diffusive transport equations, and updating iteratively an accommodation at the end of each of the sequences by preconditioning a residue between the current thicknesses of the sedimentary sequences and calculated thicknesses.

2. A method as claimed in claim 1, wherein the accommodation at the end of a given sequence is initialized by the accommodation at the end of the sequence provided by a stationary diffusive model

3. A method as claimed in claim 1, wherein preconditioning is obtained by application to the residue, on the thicknesses, of a tangent stationary diffusive model.

4. A method as claimed in claim 1, wherein an initial accommodation of a sequence is determined by a final accommodation calculated for the sequence located immediately below a sequence which is considered.

5. A method as claimed in claim 1, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

6. A method as claimed in claim 1 wherein, when close to convergence, updating the accommodation at the end of each of the sequences is obtained by calculation of a Newton step of an inverse problem.

7. A method as claimed in claim 6, wherein the Newton step of the inverse problem is calculated by means of a GMRES type iterative algorithm preconditioned by a tangent stationary model.

8. A method as claimed in claim 2, wherein preconditioning is obtained by application to the residue, on the thicknesses, of a tangent stationary diffusive model.

9. A method as claimed in claim 2, wherein an initial accommodation of a sequence is determined by a final accommodation calculated for the sequence located immediately below a sequence which is considered.

10. A method as claimed in claim 3, wherein an initial accommodation of a sequence is determined by a final accommodation calculated for the sequence located immediately below a sequence which is considered.

11. A method as claimed in claim 8, wherein an initial accommodation of a sequence is determined by a final accommodation calculated for the sequence located immediately below a sequence which is considered.

12. A method as claimed in claim 2, wherein mean values in time of the sedimentary supply for a sequence are considered in the stationary and tangent stationary models.

13. A method as claimed in claim 3, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

14. A method as claimed in claim 4, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

15. A method as claimed in claim 8, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

16. A method as claimed in claim 9, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

17. A method as claimed in claim 10, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

18. A method as claimed in claim 11, wherein mean values in time of the sedimentary supply for a sequence are considered in stationary and tangent stationary models.

19. A method as claimed in claim 2 wherein, when close to convergence, updating the accommodation at the end of each of the sequences is obtained by calculation of Newton step of an inverse problem.

20. A method as claimed in claim 3 wherein, when close to convergence, updating the accommodation at the end of each of the sequences is obtained by calculation of Newton step of an inverse problem.