Method for Visualizing Multi-Component Seismic Data Including Rotational Data

Abstract

The present invention provides visualization of a seismic wavefield as measured by various multi-component sensors, including, but not limited to, pressure, 3-component vector spatial pressure gradients, 3-component linear motion, and 3-component rotational motion. The visualization of the present invention employs combinations of dynamic displacement; dynamic rotation; dynamic dilation and compression; and dynamic color and transparency variations to display various measurements of a seismic wavefield. The visualization of the present invention may be applied to various seismic data sets, including, but not limited to, pre-stack data sets; post-migration data volumes; micro-seismic passive or active source monitoring; and vertical seismic profiles. The method has a wide range of application in seismic surveys in oil and gas exploration and production.

Description

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit under 35 USC §119 (e) of U.S. Provisional Patent Application No. 61/859455 filed on Jul. 29, 2013, the disclosure of which is incorporated herein by reference.

FIELD

The present invention pertains to the art of seismic surveying for the exploration and production of petroleum reservoirs, and more specifically to the visualization and interpretation of linear motion, pressure, pressure gradients, and rotational seismic data in 3D or 4D surveys, in micro-seismic surveys, and in vertical seismic profiles.

BACKGROUND

There is a long term trend in seismic reflection surveying for oil and gas exploration and production to utilize more attributes of seismic data in interpreting rock and fluid properties.

It is well understood in many fields of physical science and engineering that a complete representation of mechanical motion requires the measurement of six degrees-of-freedom. Typically this is accomplished by measuring three orthogonal linear motions, and measuring rotations around three orthogonal axes.

There is a well-established technology for measurement of the linear particle motion of seismic wavefields in the earth. Many commercial sensors exist to measure particle velocity or particle acceleration along one, or up to three, linear axes, utilizing various physical concepts to accomplish the measurements. It is most common to utilize measurements of the vertical particle motion. On the water bottom linear particle motion sensors are commonly deployed, typically along with pressure sensing hydrophones, in Ocean Bottom Cables or in Ocean Bottom Nodes.

There is an evolving commercial technology for measurement of the rotational particle motion of seismic wavefields in the earth. This includes sensors such as those commercially offered by, for example, MetTech (model Metr-3) and Eentec (models R-1 and R-2).

The utility of rotational seismic measurements is appreciated in earthquake and regional crustal seismology, as discussed, for example, in Lee, W., et al., eds., Rotational Seismology and Engineering Applications, Bull. Seismological Society of America, Vol. 99, no. 2B, supplement, May, 2009. Seismic rotational motion is commonly understood to be the vector curl of the infinitesimal displacement field. The existing rotational sensors are understood to measure the components of this vector curl.

Some various possible uses of rotational seismic data in oil and gas geophysics have been discussed in technical presentations. See, for example, Aldridge, D., et al., Theta-Data: Introduction to Rotational Seismology and its Potential Uses, 2012, Presentation at SEG meeting, Las Vegas. See also Muyzert, E., et al., Land Seismic Data Acquisition Using Rotation Sensors, 2012, presentation at EAGE meeting, Copenhagen. See also Edme, P., et al., Rotational data Measurement, 2013, presentation at EAGE meeting, London. See further Barak, O., et al., Seven-component seismic data, 2013, Presentation at SEG Convention, Houston, Tex.

There is a well-established technology to measure pressure changes due to a seismic wavefield. There is also an evolving sensor technology to measure the gradient of pressure within seismic wavefields. These measurements may yield up to three vector components of pressure gradient. See, for example, U.S. Pat. No. 7,295,494 to Meier entitled “Diamagnetic Current Response Transducer for Sensing Pressure Gradient in a Fluid Medium”. Commercial pressure gradient sensors, so-called vector hydrophones, are available, as for example, from Benthowave.

Persons having ordinary skill in the art will recognize that there are a number of technologies that comprise typical display prior art relative to the present invention. These include the common use of various display technologies such as wiggle trace, variable area, and variable density displays of seismic data. These are routinely used for 1-component data, and may be used for multi-component seismic data displays by displaying each component separately.

Further, it is common practice to display 3-D or 4-D seismic data volumes utilizing techniques such as time slice and horizon slice displays. It is common to utilize displays of many diverse different seismic attributes, many of which are chosen so as to highlight changes within the seismic data volumes. References that exhibit many various prior art displays of 3-D seismic data, utilizing many various calculated attributes, include Brown A., Interpretation of Three-Dimensional Seismic Data, 2004, 6th edition, American Assoc. Petroleum Geologists. See further Chopra Satinder and Kurt Marfurt, Seismic Attributes—a promising aid for geologic prediction, 2006 CSEG Recorder Special Edition pp 110-121. None of the diverse attributes and displays in prior art have been applied to rotational seismic data.

Prior art displays of linear multi-component seismic data have sometimes included hodographs. These have been used to show, for example, elliptical loops of motion of a point for ground roll waves. However, these hodographs do not represent vector curl rotation, and have not been used with rotational seismic data.

Additional prior art technologies are available for immersive displays of 3-D and 4-D seismic data volumes. These existing technologies can include immersive room environments for visualization of seismic data volumes.

It is common practice to utilize dynamic displays of seismic data volumes by means of, for example, so-called seismic movies that may depict changes of various seismic attributes over some depth range, or two-way travel-time range.

In general computing, beyond seismic applications, there have been many developments in computer graphics, including 3-D visualization and dynamic displays to simulate real time, such as in gaming systems. Further it is common in various consumer electronics to utilize 3-component linear acceleration sensors and 3-axis rotational motion sensors.

There are various technologies for recording and utilizing linear multi-component seismic data. Typically this is done for purposes of trying to utilize converted wave (shear wave) data. These techniques have been the subject of many industry courses, such as that taught by Stewart and Gaiser, Application and Interpretation of Converted Waves, a Society of Exploration Geophysicists Course.

There is technology to record multi-component seismic data that can include pressure data, pressure gradient data, 3-C linear motion data, and 3-Theta rotational motion data. There have been various display techniques developed to facilitate the visualization of seismic volumes for 1-component and for multi-component data.

There is presently an unmet need for an efficient and effective means to visualize multi-component data, with a particular need for means to display rotational seismic data, and a particular need to visualize multiple components simultaneously.

SUMMARY

In one embodiment there is provided a method for visualize multi-component seismic data comprising a plurality of display element volumes, sometimes referred to as SeisBalls, which dynamically can change position, change size, change shape, change color, and rotate to represent seismic motion including linear motion with up to 3-Components, rotational motion with up to 3-Theta components, scalar pressure, and Pressure Gradient with up to 3-Component

In another embodiment there is provided a system to visualize multi-component seismic data comprising one or more display devices, and software to display one or more display element volumes which dynamically can change position, change size, change shape, change color, and rotate to represent seismic motion including linear motion for 1, 2, or 3 Components, rotational motion for 1, 2, or 3 Theta components, scalar pressure, and Pressure Gradient for 1, 2, or 3 Components.

Further embodiments are disclosed herein or will become apparent to those skilled in the art after having read and understood the specification and drawings hereof. This summary may be more fully appreciated with respect to the following description and accompanying figures and attachments.

BRIEF DESCRIPTION OF THE DRAWINGS

Different aspects of the various embodiments of the invention will become apparent from the following specification, drawings and claims in which:

FIG. 1 is a diagrammatic representation of the use of SeisBall motion and parallax to depict linear seismic motion components;

FIG. 2 is a diagrammatic representation of SeisBall rotation to depict rotational seismic motion components;

FIG. 3 is a diagrammatic representation of the use of SeisBall size to depict pressure;

FIG. 4 is a diagrammatic representation of the use of SeisBall color to depict pressure;

FIG. 5 is a diagrammatic representation of the use of SeisBall shapes to depict pressure gradients;

FIG. 6 is a diagrammatic representation of the use of SeisBall color gradients to depict pressure gradients;

FIG. 7A is a diagrammatic representation of a time- or horizon-slice of a 3-D seismic volume, utilizing a rectangular grid of SeisBalls;

FIG. 7B is a diagrammatic representation of a time- or horizon-slice of a 3-D seismic volume, utilizing a hexagonal grid of SeisBalls and

FIG. 8 is a diagrammatic representation of the visualization of polarization trends in a horizon-slice of a 3-D seismic volume.

The drawings are not necessarily to scale. Like numbers refer to like parts or steps throughout the drawings.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

Before proceeding with the detailed description, it is to be appreciated that the present teaching is by way of example only, not by limitation.

In the following description, specific details are provided to impart a thorough understanding of the various embodiments of the invention. Upon having read and understood the specification, claims and drawings hereof, however, those skilled in the art will understand that some embodiments of the invention may be practiced without adhering to some of the specific details set forth herein. Moreover, to avoid obscuring the invention, some well-known methods, processes and devices and systems finding application in the various embodiments described herein are not disclosed in detail. Persons having ordinary skill in the art will recognize that there may be many implementation-specific details that are not described here, but that would be considered part of a routine undertaking to implement the inventive concepts of the present invention.

Several embodiments of the present invention are discussed below. The appended drawings illustrate only typical embodiments of the present invention and therefore are not to be considered limiting of its scope and breadth. In the drawings, some, but not all, possible embodiments are illustrated, and further may not be shown to scale.

The object of the present invention is to improve the ability to visualize multi-component seismic data, particularly for data sets including rotational seismic data, by using a novel combination of visualization techniques

The invention includes, in its many aspects and embodiments, a method to enhance the visualization of multi-component seismic data. The invention enhances the ability to visualize and analyze many various attributes, aspects, and trends in seismic data including but not limited to polarizations, fracture effects, fluid effects, lithology effects, porosity effects, wavefield separations, and wave propagation effects. More particularly the method comprises: selecting some or all of linear motion, rotational motion, pressure, and pressure gradient seismic data; and by means of dynamic animation/motion, color, size, and shape, displaying said seismic data in a manner to allow visualization of multiple components simultaneously.

Seismic data volumes consist of sets of traces which are time series of a particular component of motion. Said data sets are typically organized in various geometric orderings such as common source (i.e., shot records), common receiver, or common midpoint. For 3-D and 4-D data sets there are various binning schemes for the data sets that are also possible. Typical prior art displays consist of time series, or of time slice or horizon slices of a 3-D or 4-D seismic data volume.

Multi-component seismic data includes multiple components recorded for one or more common geometric locations, such as receiver locations or common midpoints. To display multi-component seismic data, prior art typically utilizes multiple time series or multiple time- or horizon-slices. In the present invention, a finite representative display element is utilized to simultaneously depict one or more of the multiple components at a particular geometric location. This representative display volume is typically a finite volume, rather than a point or areal element, and typically is generally spheroidal in shape, although it may change shape or size as part of the inventive display. An aspect of the present invention is the use of use of such a dynamically portrayed element, sometimes referred to as a SeisBall, to portray seismic wavefields representative of a voxel element within a seismic data volume that is a representation of the subsurface of the earth. A SeisBall is any solid body including, but not limited to, a sphere, an ellipsoid, a distorted sphere, a distorted ellipsoid, or any other relatively compact body.

It is well known that six degrees of freedom are required for a complete description of motion of a finite body, such as a part of the earth. Typically three linear components may be measured at two nearby points, or three linear and three rotational components may be measured at any one point.

In a simple isotropic homogeneous model of the earth it is well known that the divergence of the infinitesimal vector displacement vector wavefield is representative of pressure, and is a scalar representation of, selectively, compressional seismic waves rather than shear seismic waves. Further, it is well known that the vector gradient of the scalar pressure wavefield is a vector representation of, selectively, compressional seismic waves rather than shear seismic waves.

In the present invention, the multiple components to be displayed may be selected as some or all of: three linear motions, rotations around three axes, pressure, and three components of pressure gradient. The present invention enables the ability to visualize wavefield components that nominally represent separate modes of propagation such as compressional waves or shear waves.

FIG. 1 depicts three orthogonal linear axes, 1-3, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 4 undergoes linear motion, shown for example, between positions 5 and 6. The x and y linear seismic motions are portrayed as linear shifts within the plane of the display. The z linear seismic motion is portrayed by changes in the size of the SeisBall utilizing simple parallax.

For such displays of 3-Component linear seismic motion, it is necessary to scale/amplify the “earth” motions to appropriate “display” motions. Such scaling/amplification can be done by means of an appropriately chosen scalar applied to each of the components of linear motion. For example, in general, “earth” motions may be microns, whereas “display” motions on a graphics display device may be millimeters, or perhaps larger. An appropriate scalar can also be chosen for use in representing the third linear axis, in and out of the plane of a planar display, in a numerically scaled parallax display. These scalars can be applied to each successive time sample in a display. Measured and recorded 3-Component linear motion seismic data often are particle velocity or particle acceleration data. As desired, these data may be numerically integrated or differentiated before display, performed separately on each component. This can be done, for example, if it is desired to display 3-Component displacements.

FIG. 2 depicts three orthogonal linear axes, 201-203, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 204 employs a patterned surface so as to render rotations readily visible. The SeisBall undergoes rotational motion that depicts rotational seismic motion components.

In general physics prior art there are multiple ways to numerically represent rotational motions, such as Euler angles with various conventions, rotation matrices, quaternions, and other techniques. Persons having ordinary skill in the art will understand that seismic rotational motions experienced in the earth during oil and gas seismic surveys are typically very small angles, on the order of milli-radians or micro-radians. For these motions, the concepts of infinitesimal rotations are appropriate. It is noted that rotational seismic sensors, such as those from MetTech, Eentec, or Applied Technology Associates measure rotations around all 3 orthogonal axes simultaneously. These sensors operate in the manner described by the known theory of Simultaneous Orthogonal Rotation Angles. Such a measurement of rotation can be expressed in terms of a single rotation angle around an appropriately determined single axis of rotation. There is a well-known Euler's Theorem of Rotation that states that such a single angle of rotation around a properly chosen single angle of rotation can represent any possible rotation, when there is some single relative fixed point of reference for the rotation.

In the present invention it is typically necessary for display purposes that the angles must be amplified, typically by orders of magnitude, in which case the ordering of rotations is significant if using technologies such as Euler angles. We have “earth” rotations in the earth that are very small, and for which the order of Euler angle rotations doesn't matter. In contrast, we also have “display” rotations that are large, and for which the order of rotations does matter if using certain technologies such as Euler angles.

Present typical rotational seismic sensors measure rotational velocity. It is well-understood that each of the 3-Theta components can be numerically integrated to obtain displacement relative to some arbitrary starting position. Rotational displacement can thus be utilized for display, if desired. Each time sample of the rotational data can be scaled/amplified as appropriately for display.

For some embodiments, one technology that can be used is the Rodrigues Equation for rotation. The appropriate single axis of rotation from “earth” rotational motion is used for the “display rotation”. However, the angle of rotation around this axis can be scaled/amplified as appropriate for visual display. For example, in general, “earth” rotational motion may be scaled from approximate orders of magnitude of micro-radians or milli-radians to “display” rotational motion which may be of the approximate order of magnitude of tenths (0.1) of a radian for larger rotations, so as to be readily visible.

There is also a well-developed technology of utilizing quaternions to numerically represent and display rotations in various applications such as consumer electronics and computer gaming systems. See, for example, Hanson, A. J., Visualizing Quaternions, 2006, Morgan Kaufmann Publishers. For some embodiments, quaternion technology can enable the ability to handle large rotational angles, such as needed for rotating SeisBall displays in the present invention.

Persons having ordinary skill in the art will understand that to properly amplify rotational motions for display, it is critical to note the particular technologies and algorithms, such as Euler angles, Rodrigues equation, quaternions, or others that may be employed in any display software systems being utilized. Persons having ordinary skill in the art will recognize that in many cases it will be best, or necessary, to refer to the “earth” rotations for purposes such as updating from one display depiction to another at a different depth or two-way travel-time within a seismic data volume.

FIG. 3 depicts three orthogonal linear axes, 301-303, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 304 undergoes changes in size to portray different pressures, as for example seen at 305 and 306.

FIG. 4 depicts three orthogonal linear axes, 401-403, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 404 undergoes changes in color, or intensity of illumination, to portray different pressures, as for example seen at 405 and 406, which diagrammatically represent the same location on the earth, but at different two-way travel-times or depths within the earth. The transitions 407 are enabled by gradational changes in color or intensity.

FIG. 5 depicts three orthogonal linear axes, 501-503, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 504 undergoes changes in shape to portray different pressure gradients, as for example seen at 505 and 506, which diagrammatically represent the same location on the earth, but at different two-way travel-times or depths within the earth. The transitions 507 are enabled by gradational changes in shape.

FIG. 6 depicts three orthogonal linear axes, 601-603, which are conceptually centered on the geometric point at which seismic motion is to be displayed. A SeisBall element 604 undergoes changes in color gradient to portray different pressure gradients, as for example seen at 605 and 606, which diagrammatically represent the same location on the earth, but at different two-way travel-times or depths within the earth. The transitions 607 are enabled by gradational changes in color gradient.

Pressure Gradient data due to seismic wavefields may be scaled/amplified as appropriate for displays, such as in FIG. 5 and FIG. 6, by means of multiplicative scalars applied to each individual component of the Pressure Gradient.

The use of color on SeisBall display elements, such as for Pressure or Pressure Gradients, can be done by arbitrary assignment of color palettes as appropriate for the display devices being utilized. Color palettes are scaled appropriately for the maximum and minimum data values to be displayed.

FIG. 7 is a diagrammatic representation of a time- or horizon-slice of a 3-D seismic volume, utilizing rectangular or hexagonal grids of SeisBalls, as depicted in FIG. 7A and FIG. 7B, respectively. Horizontal axes, x and y are shown as 701 and 702. Such axes may represent Easting and Northing coordinates in a map of the earth. Each SeisBall 703 or 704 represents a bin within a grid in the x-y plane. The dimensions of bins typically range from approximately 6.25 meters to 50 meters, or more, or less. Each SeisBall 703 or 704 can represent a voxel volume element within the earth, for a particular time-slice or horizon slice within a seismic data volume.

FIG. 8 is a diagrammatic representation of a time- or horizon-slice of a 3-D seismic volume, utilizing rectangular or hexagonal grids of SeisBalls. Horizontal axes, x and y are shown as 801 and 802. Each SeisBall 803 represents a bin within a grid in the x-y plane. Each SeisBall 803 can represent a voxel volume element within the earth, for a particular time-slice or horizon slice within a seismic data volume. For each SeisBall voxel element, an orientation of the polarization of rotational motion is shown, such as to allow visualization of the trends of polarization over geologically meaningful areas.

In various embodiments that display polarization trends, statistical processing can be utilized to enhance the visibility of trends. Statistical techniques, including Fisher statistics and others, may be used for calculations regarding polarization axis orientations in a three-dimensional spherical sense. Statistical and filtering techniques may be used within time and/or depth windows, and within horizontal spatial windows.

In the present invention, many combinations of the display concepts shown above are utilized. The present invention includes, among other combinations, the means to simultaneously view:

• • 3-C linear and 3-Theta rotational motions
  • 3-C linear, 3-Theta rotational, and scalar Pressure
  • 3-Component Pressure Grad and 3-Theta rotational
  • Scalar Pressure and 3-Theta rotational

In the present invention, successive seismic two-way travel-time or depth samples of the inventive displays of seismic data are to be displayed in many embodiments, analogous to prior art practice of displaying 3-D seismic conventionally. The inventive displays can be static at a particular time or depth level. They can be animated such as to portray a ‘movie’ with successive movie frames for successive time or depth levels. These movie type displays may be played at various speeds. Movie type displays may be cycled repeatedly through some specified time or depth window range.

Further, the inventive displays can portray SeisBall elements at a particular static two-way travel-time or depth level, wherein the motions are animated at a speed that is proportional to the instantaneous frequency of the various seismic components. Alternatively, in some embodiments an animation speed may be arbitrarily chosen based on subjective visual judgment.

In some embodiments, 3-Theta rotational data are represented by rotating SeisBalls.

In some embodiments, 3-Component linear earth motion is represented by exaggerated parallax for linear motion of SeisBalls.

In some embodiments, 3-component Pressure gradient is represented by color gradations across SeisBalls

In some embodiments, Pressure is represented by the size of SeisBalls, by the color of the SeisBalls, or by the intensity of illumination of the SeisBalls.

In some embodiments, up to ten components are visually represented, including some or all of: 3-Components of linear motion, 3-Theta components of rotational motion, 3 components of Pressure Gradient, and scalar Pressure.

In some embodiments 3-D or 4-D seismic data are represented by a 2-Dimensional square, rectangular, or hexagonal grid of SeisBalls.

In many embodiments, combinations of linear motion, rotational motion, color changes, shape changes and size changes of SeisBalls are utilized. The present invention enables the display of multi-component seismic data, up to ten components, in various combinations.

A limited number of embodiments have been described herein. Those skilled in the art will recognize other embodiments within the scope of the claims of the present invention.

It is noted that many of the structures, materials, and acts recited herein can be recited as means for performing a function or step for performing a function. Therefore, it should be understood that such language is entitled to cover all such structures, materials, or acts disclosed within this specification and their equivalents, including any matter incorporated by reference.

It is thought that the apparatuses and methods of embodiments described herein will be understood from this specification. While the above description is a complete description of specific embodiments, the above description should not be taken as limiting the scope of the patent as defined by the claims.

Other aspects, advantages, and modifications will be apparent to those of ordinary skill in the art to which the claims pertain. The elements and use of the above-described embodiments can be rearranged and combined in manners other than specifically described above, with any and all permutations within the scope of the disclosure.

Although the above description includes many specific examples, they should not be construed as limiting the scope of the method, but rather as merely providing illustrations of some of the many possible embodiments of this method. The scope of the method should be determined by the appended claims and their legal equivalents, and not by the examples given.

Claims

1. A method for visualize multi-component seismic data comprising a plurality of display element volumes, sometimes referred to as SeisBalls, which dynamically can change position, change size, change shape, change color, and rotate to represent seismic motion including linear motion with up to 3-Components, rotational motion with up to 3-Theta components, scalar pressure, and Pressure Gradient with up to 3-Components.

2. The method of claim 1 wherein dynamic spinning motion is used to depict rotational seismic motion for 1, 2, or 3-Theta components.

3. The method of claim 1 wherein dynamic linear vibrational motion with exaggerated parallax is used to depict linear seismic motion for 1, 2, or 3 Components.

4. The method of claim 1 wherein color changes are used to depict temporal scalar pressure changes due to seismic wavefields.

5. The method of claim 1 wherein color changes are used to depict spatial scalar pressure gradients due to seismic wavefields, for 1, 2, or 3-Components of Pressure Gradient.

6. The method of claim 1 wherein changes in the size of the display element volumes are used to depict temporal scalar pressure changes due to seismic wavefields.

7. The method of claim 1 wherein changes in the shape of the display element volumes are used to depict spatial pressure gradients due to seismic wavefields, for 1, 2, or 3 Components of Pressure Gradient.

8. A system to visualize multi-component seismic data comprising one or more display devices, and software to display one or more display element volumes which dynamically can change position, change size, change shape, change color, and rotate to represent seismic motion including linear motion for 1, 2, or 3 Components, rotational motion for 1, 2, or 3 Theta components, scalar pressure, and Pressure Gradient for 1, 2, or 3 Components.