Checkshot_Survey

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General Information

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Name Checkshot_Survey
Entity Type Table
Description The checkshot is used to associate travel time (a measure of velocity) with each of a number of depths in a well. This can be used to understand the velocity relationship between depths and two-way acoustic travel times. This is an important bridge between seismic data and the known geophysical properties in the vicinity of the well. (Geoshare DM)
Submodel Velocity
Entity Scope Project
Primary Key Id
Natural Key
Generalizations Velocity_Function , Entity , IT_Object , Tracked_Object
Specializations


Columns

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NameValue DomainProperty /
Storage Unit		DescriptionRequired /
Default		Type
Acquisition_Date DATE NA
 The date on which the checkshot survey was run. No
 DATE
Area_Of_Validity_Id Area
The area in which the velocity function is considered valid. No
 NUMBER(38)
Borehole_Id Borehole
The borehole in which the checkshot was acquired or is attributed to. No
 NUMBER(38)
Bulk_Array_Id Bulk_Array
The bulk array that stores the time depth pairs of a checkshot survey. No
 NUMBER(38)
Corrected_Time_Flag boolean NA
 This flag denotes whether the time picks in the checkshot are times corrected for source offset and elevation(1) or raw uncorrected times(0). Yes
1		 NUMBER(1)
Correction_Velocity double Acoustic_Velocity
m/s		 The velocity used to correct this function to the datum. No
 NUMBER
Datum_Elevation double Length
m		 The elevation of the datum to which the velocity - Z pairs are referenced. This may differ from the Seismic Reference Datum. The elevation is relative to the Vertical_Reference of the Velocity_Set No
 NUMBER
Depth_Property R_Property
The depth property used for Velocity_Datum_Depth time-depth pairs, for example, True_Vertical_Depth or Measured_Depth. Yes
 VARCHAR2(64)
Depth_Vertical_Reference_Id Coordinate_System
The coordinate system in which the checkshot depth datum is defined as the vertical reference. Yes
 NUMBER(38)
Existence_Kind REF_EXISTENCE_KIND NA
 A reference value that describes the state of existence in the lifecycle of the entity, for example, Planned, Predicted, Required, Simulated, and Actual. Yes
Actual		 VARCHAR2(64)
GUID STRING128 NA
 Globally Unique IDentifier for an instance of a class. USAGE NOTES: There are two cases: 1) GUID is not populated or used; and 2) it is populated with a value that is globally unique. If the GUID is populated there are two means of doing so for a given project: 2a) Seabed automatically generates and populates the GUID when an instance is created (valid only on Oracle based systems); and 2b) the GUID is generated and populated by an application (other than Seabed) on instance creation. Whether Seabed automatically generates GUIDs for a project is determined by the Auto_GUID flag in SDS_Account. Note that techniques 2a and 2b can coexist in the same project. When GUIDs are automatically generated an application can override the automatically generated GUID with its own GUID by simply supplying the GUID value. Applications that generate their own GUIDs and populate the GUID column will function correctly on projects which have automatic GUID generation turned on. No
 VARCHAR2(128)
Id ID No_Unit
 Unique identifier for this entity. Yes
 NUMBER(38)
Index_Correction double No_Unit
 Delta index correction value in the same units as the INDEX channel (time or depth). This value, when added to the INDEX vector values can be used for correction from the function datum to the set datum this correction can be performed even if the Datum_Elevation is null. Times are always two-way acoustic travel times. No
 NUMBER
Insert_Date DATE NA
 Date the entity was created in the repository No
 DATE
Insert_User STRING64 NA
 The name of the user responsible for the creation of this entity in the repository. No
 VARCHAR2(64)
Interpretation_Status R_Survey_Interp_Status
The interpretation status of the checkshot survey. For example Raw, Processed No
 VARCHAR2(64)
Logging_Activity_Id Logging_Activity
The logging activity corresponding to the checkshot acquisition and processing. No
 NUMBER(38)
Name ENTITY_NAME NA
 The name given to any object or data item, e.g. name of Well, name of Field, etc. No
 VARCHAR2(255)
Original_Deviation_Survey_Id Deviation_Survey
The original deviation survey used for processing the checkshot survey. No
 NUMBER(38)
Original_Source STRING64 NA
 The name of the person, Organization or project source that originally provided this entity, e.g. "IHS-EnergyData" or "FinderUpper Stratton Deeper Pool 15" No
 VARCHAR2(64)
Preferred_Flag boolean NA
 Denotes whether this is the preferred checkshot to use for this borehole. Yes
0		 NUMBER(1)
Produced_By STRING64 NA
 The name of application role that created the entity, for data created programmatically. No
 VARCHAR2(64)
Raw_Checkshot_Survey_Id Checkshot_Survey
The raw checkshot survey from which a processed survey is computed, if available. No
 NUMBER(38)
Remarks STRING2000 NA
 Any type of remarks added to an entity instance. No
 VARCHAR2(2000)
SDAT_Label int No_Unit
 Label used by the security system for entitlements. SDAT is Secure Data Access Technology. No
 NUMBER(10)
Source STRING64 NA
 Name of the person or organization responsible for this entitys E and P content and quality. Not the data technologist or IT expert creating the entity, for which see IT_Object.Insert_User and Update_User. No
 VARCHAR2(64)
Synthetic_Point_Depth double Depth
m		 A point located between the top checkshot and the vertical reference in the depth coordinate system. It is used with the synthetic point velocity improve the velocity in the layer between the synthetic point and the top checkshot. If a checkshot survey is acquired in a vertical well in 1000 ft of water with a depth vertical reference given as sea level and the first checkshot is at 2000 ft, 1000 ft would be entered as the Synthetic_Point_Depth and 5000 ft/s as the velocity_to_datum to get a better estimate of the velocity in the layer from 1000 - 2000 ft. This assumes a 5000 ft/s water velocity. The depth is vertical depth relative to the Vertical_Reference in the Depth_Coordinate_System. No
 NUMBER
Synthetic_Point_Velocity double Acoustic_Velocity
m/s		 The average velocity from the depth vertical reference to the Synthetic_Point_Depth. This is used with the Synthetic_Point_Depth to improve the velocity of the layer between the between the Synthetic_Point_Depth and the top checkshot. The velocity is typically obtained from a priori knowledge of the near surface. No
 NUMBER
Time_Property R_Property
The time property used for time-depth pairs, One_Way_Time or Two_Way_Time. Yes
 VARCHAR2(64)
Time_Vertical_Reference_Id Coordinate_System
The coordinate system in which the time datum is defined as the vertical reference. This is an elevation not a time value. Yes
 NUMBER(38)
Update_Date DATE NA
 Date of the most-recent modification to the entity. No
 DATE
Update_User STRING64 NA
 The name of the user responsible for the last modification to this entity. No
 VARCHAR2(64)
Value_Property R_Property
The property of the function value, such as interval velocity or two way time. No
 VARCHAR2(64)
Velocity_Set_Id Velocity_Set
The collection of velocities to which this velocity location belongs, if any. No
 NUMBER(38)
Velocity_Source R_Velocity_Source
The source of the velocity data. Seismic, Seismic DMO, Seismic Migration, Pseudo Velocity, Sonic Log, Borehole (VSP,checkshot), Computed, and Refraction are the options. No
 VARCHAR2(64)
Version STRING255 NA
 The form or variant of the entity. Yes
1		 VARCHAR2(255)
Work_Order_Number STRING64 NA
 The ID number used by the vendor to reference the survey. No
 VARCHAR2(64)


Referenced By

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From EntityLinkDescriptionImplementation TechniqueRequired
Checkshot_Survey Raw_Checkshot_Survey The raw checkshot survey from which a processed survey is computed, if available. Nullify No
Seismic_Energy_Source Checkshot The checkshot that the source was used to acquire. Cascade Yes
Study_Checkshot_Survey Checkshot The identifier of a checkshot survey that is an element of the study. Nullify No
Time_Depth_Pair Checkshot The checkshot to which the time-depth pairs belong. Cascade Yes


Refers To

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LinkTo EntityDescriptionImplementation TechniqueRequired
Bulk_Array Bulk_Array The bulk array that stores the time depth pairs of a checkshot survey. Control No
Depth_Property R_Property The depth property used for Velocity_Datum_Depth time-depth pairs, for example, True_Vertical_Depth or Measured_Depth. Restrict Yes
Depth_Vertical_Reference Coordinate_System The coordinate system in which the checkshot depth datum is defined as the vertical reference. Restrict Yes
Interpretation_Status R_Survey_Interp_Status The interpretation status of the checkshot survey. For example Raw, Processed Restrict No
Time_Vertical_Reference Coordinate_System The coordinate system in which the time datum is defined as the vertical reference. This is an elevation not a time value. Restrict Yes
Time_Property R_Property The time property used for time-depth pairs, One_Way_Time or Two_Way_Time. Restrict Yes
Velocity_Set Velocity_Set _ Cascade No
Original_Deviation_Survey Deviation_Survey The original deviation survey used for processing the checkshot survey. Nullify No
Raw_Checkshot_Survey Checkshot_Survey The raw checkshot survey from which a processed survey is computed, if available. Nullify No
Borehole Borehole The borehole in which the checkshot was acquired or is attributed to. Cascade No
Area_Of_Validity Area _ Control No
Value_Property R_Property _ Restrict No
Velocity_Source R_Velocity_Source _ Restrict No
Logging_Activity Logging_Activity The logging activity corresponding to the checkshot acquisition and processing. Nullify No


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