Exxonmobil Upstream Research Company

Exxonmobil Technology and Engineering Company

Olivier M Burtz

Leonard J Srnka

Dmitriy A Pavlov

Kenneth E Green

Dennis E Willen

Scott C Hornbostel

Charlie Jing

Xinyou Lu

Leslie A Wahrmund

Rebecca L Saltzer

James J Carazzone

Mark Stiver

Denny E Willen

Jacob A Violet

Haiyang Wang

Methods for inversion of seismic data to infer subsurface physical property parameters, comprising constructing an inhomogeneous anisotropy model and/or inhomogeneous V/Vor V/Vmodel; and inverting the seismic data in a sequential or simultaneous approach to obtain at least one subsurface physical property parameter using an elastic inversion algorithm and the inhomogeneous anisotropy model and/or inhomogeneous V/Vor V/Vmodel. Constructing an inhomogeneous anisotropy model may comprise deriving geobodies from at least one of seismic facies analysis, regional geologic information, or seismically derived earth models; and adjusting at least one of &#x3b5;, &#x3b4;, &#x3b3;, or parameters of the elastic stiffness tensor matrix in a homogeneous anisotropy model in areas corresponding to the geobodies. Constructing an inhomogeneous V/Vor V/Vmodel may comprise deriving geobodies and adjusting values in a homogeneous V/Vor V/Vmodel in areas corresponding to the geobodies.

Elastic full wavefield inversion with refined anisotropy and V/Vmodels

Systems and methods which provide electromagnetic subsurface mapping to derive information with respect to subsurface features whose sizes are near to or below the resolution of electromagnetic data characterizing the subsurface are shown. Embodiments operate to identify a region of interest () in a resistivity image generated () using electromagnetic data (). One or more scenarios may be identified for the areas of interest, wherein the various scenarios comprise representations of features whose sizes are near to or below the resolution of the electromagnetic data (). According to embodiments, the scenarios are evaluated (), such as using forward or inverse modeling, to determine each scenarios' fit to the available data and further to determine their geologic reasonableness (). Resulting scenarios may be utilized in a number of ways, such as to be substituted in a resistivity image for a corresponding region of anomalous resistivity for enhancing the resistivity image ().

Systems and methods for subsurface electromagnetic mapping

There is provided a system and method for creating a physical property model representative of a physical property of a region. An exemplary method comprises transforming information from a model domain that represents the physical property model into simulated data in a data domain, the data domain comprising simulated data and measured data representative of a plurality of observations of the region. The exemplary method also comprises determining an areal misfit between the simulated data and the measured data representative of the plurality of observations of the region. The exemplary method additionally comprises performing an evaluation of the areal misfit based on known criteria. The exemplary method comprises adjusting data in the data domain or information in the model domain corresponding to a region in the model domain based on the evaluation of the areal misfit.

System and method for providing a physical property model

Method for improving frequency-domain (), controlled-source electromagnetic data readability and interpretability in hydrocarbon prospecting by mapping a scaled amplitude or the relative amplitude (or phase) of the electromagnetic field in a scaled offset&#x2212;scaled frequency plane (). The preferred mapping space uses the offset times the square-root of the frequency as the X-axis and the square-root of the frequency as the Y-axis. The preferred way to scale the amplitude of the electric field is to multiply it by the frequency to the power of &#x2212;1.5. Resistive anomalies in the data may be identified by comparing negative offset data (or data relative to a reference) to positive offset data (). The location and size of a potentially hydrocarbon-bearing resistive body may be estimated from the position of the anomaly on the map ().

Scaled plots of electromagnetic data

A structured computer-implemented method () based on graphical user interfaces for interpretation and mapping of data from a controlled-source electromagnetic survey, featuring capability to store electromagnetic data in layers (), each layer having the same internal structure for ease of comparison, editing, display and other manipulation by an assortment of software tools () useful to an interpreter. Thus, different layers might contain actual data () from different surveys and simulated results () based on different resistivity models or inversion results (), all pertaining to the same subterranean survey region.

Interpretation and mapping of electromagnetic survey data

A method is disclosed for determining earth vertical electrical anisotropy from offshore electromagnetic survey measurements. The method requires both online and offline data, which includes at least one electromagnetic field component sensitive at least predominantly to vertical resistivity and another component sensitive at least predominantly to horizontal resistivity. Using a horizontal electric dipole source, online Eand offline Hmeasurements are preferred. For a horizontal magnetic dipole source, online Hand offline Edata are preferred. magnetotelluric data may be substituted for controlled source data sensitive to horizontal resistivity. Maxwell's equations are solved by forward modeling or by inversion, using resistivity models of the subsurface that are either isotropic or anisotropic.

Method for determining earth vertical electrical anisotropy in marine electromagnetic surveys

Method for enhancing resistive anomalies in electromagnetic geophysical survey data. Scaled values of a measured electromagnetic field parameter are plotted on a depth section at locations related to corresponding source/receiver locations. Scaling is performed relative to a reference signal selected to represent a baseline free of unknown resistive bodies. Scaled values are represented by a color scale in the display, and the color scale may be adjusted to enhance perceived anomalies. The method may be employed in either the frequency domain or the time domain.

Method for identifying resistivity anomalies in electromagnetic survey data

Method for removing effects of shallow resistivity structures in electromagnetic survey data to produce a low frequency resistivity anomaly map, or alternatively imaging resistivity structures at their correct depth levels. The method involves solving Maxwell's electromagnetic field equations by either forward modeling or inversion, and requires at least two survey data sets, one taken at the source frequency selected to penetrate to a target depth, the other a higher frequency able to penetrate only shallow depths.

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Houston, TX, United States of America

Olivier M Burtz