The Necessity of a PEM Constraint for Joint Inversion of Amplitude and Time-Shift Data

Research output: Chapter in Book/Report/Conference proceedingConference contribution


Quantitative interpretation of 4D seismic data involves the challenging step of inverting to localized velocity (∆v/v) and impedance (∆I/I) changes. This difficulty is greatest in reservoir sections due to the entanglement of amplitude and time-shift changes. The petroelastic model (PEM) offers a crucial link between ∆v/v and ∆I/I, contributing to the robustness of the 4D inversion that jointly inverts time-shifts and amplitude. Past studies utilise different approximations for the PEM, varying from an equality to proportionality. This study assesses the impact of the choice of the PEM approximation on 4D inversion accuracy using a controlled dataset modelled from observed field data. Non-linearities arise in the relationship between ∆v/v and ∆I/I due to gas saturation and pressure changes. The results show that assuming equality or proportionality leads to high residuals, whilst a trilinear PEM approximation may just be sufficient. However, gas and pressure non-linearities still pose a challenge even when an exact PEM is used. The study emphasizes the importance of a well-calibrated PEM in 4D inversion to reduce uncertainties, and highlights the ultimate limits of the method.
Original languageEnglish
Title of host publication85th EAGE Annual Conference & Exhibition 2024
Place of PublicationOslo, Norway
PublisherEAGE Publishing BV
Number of pages5
ISBN (Print)9789462824980
Publication statusPublished - 10 Jun 2024
Event85th EAGE Annual Conference & Exhibition 2024 - Oslo, Norway
Duration: 10 Jun 202413 Jun 2024


Conference85th EAGE Annual Conference & Exhibition 2024


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