Exxonmobil Upstream Research Company

Young Ho Cha

Jerome R Krebs

Sunwoong Lee

Dennis E Willen

John E Anderson

Michael W Norris

Partha Sarathi Routh

Pavel Dimitrov

Anoop A Mullur

William Curry

Nathan Downey

Haiyang Wang

A method and apparatus for hydrocarbon management including generating an image of a subsurface formation by: obtaining simultaneous-source survey data, an earth model, and a first and a second velocity model of the subsurface formation; generating synthetic survey data with at least one of the earth model, the first velocity model, and the second velocity model. The method and apparatus may include directly migrating the simultaneous-source survey data; migrating the synthetic survey data; and subtracting the migrated synthetic survey data from the migrated simultaneous-source survey data. The method and apparatus may include subtracting the synthetic survey data from the simultaneous-source survey data; and directly migrating the result of the subtraction. The method and apparatus may include generating an artifact-reduced image.

Direct migration of simultaneous-source survey data

A method for obtaining zero-offset and near zero offset seismic data from a marine survey, with separation of direct arrival information and reflectivity information, the method including: modeling a direct arrival estimate at a passive near-field hydrophone array by using a notional source separation on active near-field hydrophone data; generating reflection data for the passive near-field hydrophone array by subtraction of the modeled direct wave from data recorded by the passive near-field hydrophone array; generating near zero-offset reflectivity traces by stacking the reflection data for the passive near-field hydrophone array on a string-by-string basis or on a combination of strings basis.

Method to estimate and remove direct arrivals from arrayed marine sources

Method for performing simultaneous encoded-source inversion of geophysical data to estimate parameters of a physical property model (), especially adapted for surveys without fixed-receiver acquisition geometry, such as marine seismic surveys with moving source and receivers. The encoding functions () used on the sources to generate one or more simultaneous encoded-source gathers of data (), as well as to simulate the same (), are orthogonal or pseudo-orthogonal with respect to cross-correlation. In addition, receivers are also encoded, with the receiver encoding being designed to make a given receiver less sensitive to sources to which it was not listening during the survey (). The encoding functions may be temporal bandpass filters differing one from another by central frequency, phase, or both. Efficiency of the method may be further improved by grouping several sources into a super-source, grouping the corresponding gathers into a super-gather, and then applying the above encoding strategy.

Orthogonal source and receiver encoding

Method for reducing artifacts in a subsurface physical properties model () inferred by iterative inversion () of geophysical data (), wherein the artifacts are associated with some approximation () made during the iterative inversion. In the method, some aspect of the approximation is changed () as the inversion is iterated such that the artifacts do not increase by coherent addition.

Artifact reduction in iterative inversion of geophysical data

Method for optimal stacking of seismic images to remove noise and enhance signals in seismic images () outputted from a Reverse Time Migration (RTM) imaging process. Dip information is calculated () and then sorted by image point (), for each seismic image to be stacked. A dominant dip and azimuth is determined at each image point (), and only those events are stacked (). If the image is still noisy or lacking in detail (), the process may be iterated () to improve the selection of most likely dip and azimuth.

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Houston, TX, United States of America

Young Ho Cha