A prestack seismic inversion method based on rytov-wkbj approximation

Abstract

The invention discloses a pre-stack seismic inversion method based on Rytov-WKBJ approximation. It includes the following steps: Step 1: Obtain pre-stack seismic data, pre-stack angle gather data, post-stack seismic data and logging data of the common center point of the reservoir; Step 2: Obtain depth-domain seismic data; Step 3: Use seismic horizon Data and reservoir logging data to build a low-frequency model in the depth domain; Step 4: Construct the objective function; Step 5: Use the Gauss-Newton method to solve the objective function to obtain the model update amount, and update the model disturbance amount; Step 6: If the pre-stack earthquake When the error level of both the angle gather data and the synthetic seismic data reaches the preset residual threshold, the inversion result is output, otherwise, go to step 7; step 7: update the number of iterations, return to step 4 to enter the next iteration, until the iteration terminates. The invention is applied in pre-stack seismic inversion, and can effectively and quickly simulate the complex seismic wave field of strong heterogeneity and complex geological structure reservoirs.

Description

technical field [0001] The invention belongs to the technical field of seismic exploration, in particular to a pre-stack seismic inversion method based on Rytov-WKBJ approximation. Background technique [0002] With the increasing global demand for oil and natural gas, the direction of oil and gas exploration has gradually shifted from traditional simple structural oil and gas reservoirs to complex geological structural oil and gas reservoirs [1] . These complex geological structure oil and gas reservoirs often have strong heterogeneity and lateral discontinuity. At present, conventional seismic inversion algorithms are still mainly used for research on reservoirs with relatively simple geological structures. Therefore, if such algorithms are used to predict reservoirs with relatively complex geological structures, deviations in structural and lithological predictions will be caused. For reservoirs with complex structures, due to the possible existence of faults, fractures...

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Problems solved by technology

[0018] Aiming at the inversion problem of geological models with complex geological structures with strong heterogeneity, the present invention proposes a pre-stack AVA inversion method suitable for near-surface and shallow reservoirs with strong heterogeneity and complex geological structures, which improves the inversion The precision of the result

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