US-12625290-B2 - Method and system of imaging hydrocarbon reservoirs using adaptive aperture tapering in kirchhoff depth migration

US12625290B2US 12625290 B2US12625290 B2US 12625290B2US-12625290-B2

Abstract

A method ( 600 ) and a system ( 1000 ) for generating an adaptive migration taper for a pre-stack seismic dataset are disclosed. The method ( 600 ) includes obtaining the pre-stack seismic dataset ( 602 ) and a seismic velocity model of a subterranean region ( 604 ). The method ( 600 ) also includes generating the adaptive migration taper based, at least in part, on the pre-stack seismic dataset ( 606 ), and forming a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper ( 608 ). The method ( 600 ) further includes determining a location of a hydrocarbon reservoir based, at least in part, on the migrated seismic image ( 610 ).

Inventors

Yujin Liu
Hongwei Liu
Fuhao Qin
Yi He

Assignees

SAUDI ARABIAN OIL COMPANY

Dates

Publication Date: 20260512
Application Date: 20220923

Claims (9)

1 . A method comprising: obtaining a pre-stack seismic dataset of a subterranean region; obtaining a seismic velocity model of the subterranean region; generating an adaptive migration taper based on the pre-stack seismic dataset comprising: generating a dip-constrained weight function based on a maximum dip for a depth and a first taper length, generating an adaptive weight function based on a depth index and a second taper length, and combining the dip-constrained weight function and the adaptive weight function; forming a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper; determining a location of a hydrocarbon reservoir based on the migrated seismic image; planning a wellbore path to intersect the hydrocarbon reservoir; and drilling a wellbore guided by the wellbore path.
2 . The method of claim 1 , wherein the depth index is determined from a migration impulse response.
3 . The method of claim 1 , wherein the first taper length and the second taper length are identical taper lengths.
4 . The method of claim 1 , wherein the adaptive migration taper comprises a vertical taper.
5 . The method of claim 1 , wherein the migration function is a Kirchhoff migration function based on an integral form of a wave equation that corresponds to pressure wave displacement and a pressure wave velocity as function of three-dimensional space and time.
6 . The method of claim 1 , wherein obtaining the seismic velocity model comprises performing velocity analysis on the pre-stack seismic dataset.
7 . A system comprising: a seismic acquisition system configured to obtain a pre-stack seismic dataset of a subterranean region; a seismic processing system configured to: receive the pre-stack seismic dataset, receive a seismic velocity model of the subterranean region, generate an adaptive migration taper based on the pre-stack seismic dataset comprising: generate a dip-constrained weight function based on a maximum dip for a depth and a first taper length; generate an adaptive weight function based on a depth index and a second taper length; and combine the dip-constrained weight function and the adaptive weight function, and form a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper; a seismic interpretation workstation configured to determine a location of a hydrocarbon reservoir based on the migrated seismic image; a wellbore planning system configured to plan a wellbore path to intersect the hydrocarbon reservoir; and a drilling system configured to drill a wellbore guided by the wellbore path.
8 . The system of claim 7 , wherein the depth index is determined from a migration impulse response.
9 . The system of claim 7 , wherein the migration function is a Kirchhoff migration function based on an integral form of a wave equation that corresponds to pressure wave displacement and a pressure wave velocity as function of three-dimensional space and time.

Description

BACKGROUND In the oil and gas industry, seismic surveying is commonly used to investigate subterranean structure, and subsequently in the evaluation and location of oil and gas reservoirs. In seismic surveys, a seismic source generates seismic waves which propagate through the subterranean region, reflect and refract from subterranean structure, and are subsequently detected by seismic receivers. The seismic receivers detect and store a time-series of samples of earth motion caused by the seismic waves. The collection of time-series samples recorded at multiple receiver locations generated by a seismic source at multiple seismic source locations constitutes a seismic dataset. A seismic dataset is typically processed to determine the structure of the subsurface. As part of the processing flow, seismic reflectors are imaged using migration methods such as Kirchhoff depth migration. Seismic datasets may cover large subterranean regions and may also be finely sampled, yielding large amounts of data. Therefore, computationally efficient methods for processing seismic datasets are critical to successfully imaging the subsurface. SUMMARY This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. In general, in one aspect, embodiments disclosed herein relate to methods for generating an adaptive migration taper for a pre-stack seismic dataset. The methods include obtaining a pre-stack seismic dataset and a seismic velocity model of a subterranean region. The methods also include generating an adaptive migration taper based, at least in part, on the pre-stack seismic dataset, and forming a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper. The methods further include determining a location of a hydrocarbon reservoir based, at least in part, on the migrated seismic image. In general, in one aspect, embodiments disclosed herein relate to a non-transitory computer readable medium storing a set of instructions, executable by a computer processor, the set of instructions including functionality for receiving a pre-stack seismic dataset and a seismic velocity model of a subterranean region. The set of instructions further including functionality for generating an adaptive migration taper based, at least in part, on the pre-stack seismic dataset, and forming a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper. The set of instructions still further including functionality for determining a location of a hydrocarbon reservoir based, at least in part, on the migrated seismic image. In general, in one aspect, embodiments disclosed herein relate to a system. The system includes a seismic acquisition system configured to obtain a pre-stack seismic dataset of a subterranean region; a seismic processing system configured to receive the pre-stack seismic dataset and a seismic velocity model of the subterranean region and to generate an adaptive migration taper based, at least in part, on the pre-stack seismic dataset, and to form a migrated seismic image using a migration function, the seismic velocity model, the pre-stack seismic dataset, and the adaptive migration taper; and a seismic interpretation workstation configured to determine a location of a hydrocarbon reservoir based, at least in part, on the migrated seismic image. Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 shows an example of a seismic survey in accordance with one or more embodiments. FIG. 2 illustrates a time travel-time cube in accordance with one or more embodiments. FIGS. 3A and 3B depict examples of impulse responses in accordance with one or more embodiments. FIG. 4 shows an example of dip-constrained migration aperture in accordance with one or more embodiments. FIG. 5 shows an example of a slowness field in accordance with one or more embodiments. FIG. 6 shows a flowchart in accordance with one or more embodiments. FIGS. 7A and 7B show examples of dip-constrained impulse responses in accordance with one or more embodiments. FIGS. 8A and 8B show examples of migrated seismic images in accordance with one or more embodiments. FIG. 9 shows a wellbore drilling system in accordance with one or more embodiments. FIG. 10 shows a block diagram of systems in accordance with one or more embodiments. FIG. 11 shows a system in accordance with one or more embodiments. DETAILED DESCRIPTION In the following detailed description of embodiments of the disclosure, numerous specific details are set forth in order to prov