Changes

Anticipating the availability of various seismic display types (such as stack, [[seismic migration|migration]], inversion, or attribute) is facilitated by creating several data files, each containing a different process. This allows the user to select which data type to work with. Addition of seismic data files is simple and can be done at any time during a project.

Anticipating the availability of various seismic display types (such as stack, [[seismic migration|migration]], inversion, or attribute) is facilitated by creating several data files, each containing a different process. This allows the user to select which data type to work with. Addition of seismic data files is simple and can be done at any time during a project.

Files with optional ''x''–''y'' information contain cultural or specialty information. Cultural information, that is, lease or topographic data, is considered map enhancement not critical to a project. Cultural information allows technical information and subsurface interpretations to be related to natural or man-made surface features. These files are at times used to highlight certain information to augment map displays. Examples of customized files might include man-made features (towns, roads, pipe lines, and leases), geomorphic data (waterways and topographic relief), highlighted wells (horizon penetrations, exploratory wells, and platform locations), or contour data (gravity, [[magnetics]], and bathymetry).

Files with optional ''x''–''y'' information contain cultural or specialty information. Cultural information, that is, lease or topographic data, is considered map enhancement not critical to a project. Cultural information allows technical information and subsurface interpretations to be related to natural or man-made surface features. These files are at times used to highlight certain information to augment map displays. Examples of customized files might include man-made features (towns, roads, pipe lines, and leases), geomorphic data (waterways and topographic relief), highlighted wells (horizon penetrations, exploratory wells, and platform locations), or [[contour]] data ([gravity]], [[magnetics]], and bathymetry).

===Seismic preparation===

===Seismic preparation===

Well information is used in a variety of ways. The most basic is incorporation of geological tops into the [[seismic interpretation]] ([[:file:two-dimensional-geophysical-workstation-interpretation-generic-problems-and-solutions_fig3.png|Figure 3]]). These tops are input digitally or via keyboard entry. Once in the database, this information is easily manipulated and can be used for modeling.

Well information is used in a variety of ways. The most basic is incorporation of geological tops into the [[seismic interpretation]] ([[:file:two-dimensional-geophysical-workstation-interpretation-generic-problems-and-solutions_fig3.png|Figure 3]]). These tops are input digitally or via keyboard entry. Once in the database, this information is easily manipulated and can be used for modeling.

Models generated from log data aid the seismic interpreter in relating seismic reflections to lithological information. Well tops associated with horizons on the seismic profiles fully integrate an exploration concept. Lithology types from the log model can be superimposed on the seismic traces for display or modification. By integrating a sonic log and density log (if available), one-dimensional seismograms that are created can help to identify seismic reflections representing geological interfaces. Log models can also be converted to 2-D synthetic seismic models by integrating velocity information and convolving the model with a seismic wavelet. Models can imitate seismic response to test geological concepts. Seismic resolution of geological features are determined, and simulated profiles are generated to tie wells.

Models generated from log data aid the seismic interpreter in relating seismic reflections to lithological information. Well tops associated with horizons on the seismic profiles fully integrate an exploration concept. Lithology types from the log model can be superimposed on the seismic traces for display or modification. By integrating a sonic log and [[density log]] (if available), one-dimensional seismograms that are created can help to identify seismic reflections representing geological interfaces. Log models can also be converted to 2-D synthetic seismic models by integrating velocity information and convolving the model with a seismic wavelet. Models can imitate seismic response to test geological concepts. Seismic resolution of geological features are determined, and simulated profiles are generated to tie wells.

Velocity information is important in relating geological data to seismic data. This information is derived by the interpreter from a variety of sources, the most common being check shot surveys obtained from wells, time-depth charts derived from stacked seismic data or seismic to well correlation, and velocity function curves. These data are input in digital form via digitizer pad or keyboard entry ([[:file:two-dimensional-geophysical-workstation-interpretation-generic-problems-and-solutions_fig3.png|Figure 3]]). When concatenated to a well, the wellbore, log curves, and geological tops can be displayed with the seismic. A three-dimensional velocity field can be created for conversion of time surfaces to depth maps.

Velocity information is important in relating geological data to seismic data. This information is derived by the interpreter from a variety of sources, the most common being check shot surveys obtained from wells, time-depth charts derived from stacked seismic data or seismic to well correlation, and velocity function curves. These data are input in digital form via digitizer pad or keyboard entry ([[:file:two-dimensional-geophysical-workstation-interpretation-generic-problems-and-solutions_fig3.png|Figure 3]]). When concatenated to a well, the wellbore, log curves, and geological tops can be displayed with the seismic. A three-dimensional velocity field can be created for conversion of time surfaces to depth maps.

The workstation has the capability of [[displaying seismic data]] with a wide range of vertical and horizontal preset scales. These window scales can be coupled with zoom or magnification options that provide the interpreter with countless scale combinations to view data. No longer is the interpreter confined to one or two fixed display scales or types because the data can be viewed in multiple ways. One can enlarge a limited time and shot point range within a window to focus on a particular feature of interest. Regional interpretation can optimally use decimated data. Similar effects are achieved in map view: a map can be enlarged to show each trace or reduced to show regional trends.

The workstation has the capability of [[displaying seismic data]] with a wide range of vertical and horizontal preset scales. These window scales can be coupled with zoom or magnification options that provide the interpreter with countless scale combinations to view data. No longer is the interpreter confined to one or two fixed display scales or types because the data can be viewed in multiple ways. One can enlarge a limited time and shot point range within a window to focus on a particular feature of interest. Regional interpretation can optimally use decimated data. Similar effects are achieved in map view: a map can be enlarged to show each trace or reduced to show regional trends.

Also, seismic annotation is tailored to show as much or as little information as desired. Options include the following: (1) shot point, CMP, or trace numbers; (2) seismic line ties; (3) time annotation and/or timing lines; (4) line direction; (5) line name or internal identification; (6) data file used; (7) well type or identifiers; and (8) horizon and fault intersections. Map view annotation is also a feature that is customized to the situation. Options that can be modified on the base map are (1) line, shot point, CMP, or trace numbers; (2) wells and well tops; and (3) cultural data. Customizing options for an interpreted map are (1) sequence of appearance and color of display items; (2) ribbon or contour display of a horizon; and (3) fault contours, heaves, or polygons. A similar array of options are available for perspective views.

Also, seismic annotation is tailored to show as much or as little information as desired. Options include the following: (1) shot point, CMP, or trace numbers; (2) seismic line ties; (3) time annotation and/or timing lines; (4) line direction; (5) line name or internal identification; (6) data file used; (7) [[well type]] or identifiers; and (8) horizon and fault intersections. Map view annotation is also a feature that is customized to the situation. Options that can be modified on the base map are (1) line, shot point, CMP, or trace numbers; (2) wells and well tops; and (3) cultural data. Customizing options for an interpreted map are (1) sequence of appearance and color of display items; (2) ribbon or [[contour]] display of a horizon; and (3) fault contours, heaves, or polygons. A similar array of options are available for perspective views.

Use of color further increases the dynamic range visible in the seismic display. The value of color graphic displays is increasingly recognized. Admittedly, colors may be overused by novices; however, subtle features can be brought into focus with proper use of color schemes. Color schemes can be specifically tailored to complement selected attributes and display types.

Use of color further increases the dynamic range visible in the seismic display. The value of color graphic displays is increasingly recognized. Admittedly, colors may be overused by novices; however, subtle features can be brought into focus with proper use of color schemes. Color schemes can be specifically tailored to complement selected attributes and display types.

[[Category:Integrated computer methods]]

[[Category:Integrated computer methods]]