| CPC G01V 1/282 (2013.01) [G01V 1/32 (2013.01); G01V 1/345 (2013.01); G01V 1/40 (2013.01); G01V 20/00 (2024.01); G06F 30/20 (2020.01); G01V 2210/66 (2013.01); G06F 2113/08 (2020.01)] | 20 Claims |
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1. A computer implemented method of modelling a subsurface region of the earth for hydrocarbon exploration, development, or production, the method comprising:
receiving into a processing system pre-stack seismic datasets measured for one or more locations within the subsurface region and well log datasets measured from wells within the subsurface region, wherein the seismic datasets comprise three-dimensional (3D) seismic amplitude data and wherein the well log datasets comprise core data and elastic logs;
selecting, with the processing system, key wells from among the wells based on the well log datasets;
generating, based on the seismic datasets, a geophysical model, wherein the geophysical model is 3D and wherein generating the geophysical model includes:
measuring, based on the seismic amplitude data and the well log datasets for the key wells, an amplitude variation with offset (AVO) response of the seismic amplitude data to determine whether the measured AVO response meets prescribed requirements, wherein the step of measuring AVO to determine whether the measured AVO response meets prescribed requirements includes:
performing a full waveform inversion process to generate synthetic seismic gathers using wavelets estimated from original input seismic data, convolved with reflectivity calculated from the elastic well logs, and
comparing, a measured AVO response from the synthetic seismic gathers with a measured AVO response of the processed seismic amplitude data to determine whether the measured AVO response meets prescribed requirements,
in response to determining that the measured AVO response does not meet the prescribed requirements, iteratively changing at least one seismic amplitude data processing parameter and re-processing the seismic amplitude data and repeating the step for measuring AVO at least until determining that the AVO response meets the prescribed requirements, and
performing a stochastic inversion process on the re-processed seismic amplitude data;
generating based on the well log datasets, a geological model, wherein generating the geological model includes:
defining core facies from the core data for the key wells,
generating, based on the elastic logs for the key wells and according to the stochastic inversion process of the re-processed seismic amplitude data, an elastic facies model for predicting elastic facies from elastic logs, and
associating the elastic facies with the core facies;
generating a conceptual depositional model of the subsurface region; and
integrating the generated geophysical model, geological model and conceptual depositional model into a 3D reservoir model for the subsurface region using a stochastic integration and using probabilistic models to quantify uncertainties of the 3D reservoir model by generating multiple realizations of the reservoir model capturing multiple possible scenarios, wherein the stochastic inversion process on the re-processed seismic amplitude data is performed using a same 3D grid as the 3D reservoir model, wherein the 3D grid is in a depth domain,
wherein the stochastic inversion process is performed in the depth domain on the re-processed seismic amplitude data, wherein the stochastic inversion process applies Bayesian interference and Markov Chain Monte Carlo sampling algorithms using core data and elastic logs for the key wells and a velocity model linking the depth domain and a time domain of the seismic datasets to generate the geophysical model in the depth domain,
wherein the step of generating the elastic facies model comprises:
generating, using elastic log data for the key wells and statistical analysis techniques, a reference elastic facies model defining the elastic facies,
associating the defined elastic facies with the core facies for the key wells,
applying the reference elastic facies model to elastic logs for non-key wells among the wells to predict elastic facies for the non-key wells, and
associating the predicted elastic facies with core facies from the non-key wells;
wherein the steps of generating the elastic facies model, generating the geological model and generating the geophysical model are performed in parallel; and
updating the elastic facies model, the geological model, the geophysical model, and the integrated 3D reservoir model using based on one or more of: new pre-stack seismic datasets measured within the subsurface region, and new well log datasets measured from wells within the subsurface region.
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