| 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 |
| Name | Value Domain / Measurement | Description | Required / 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) |
| 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 |
The velocity used to correct this function to the datum. | No |
NUMBER |
| Datum_Elevation | double Length |
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. This GUID is not generated by the database, but is the GUID used by the application on first access of this object. Use of this property is optional and completely under the control of application developers. | 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) |
| 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 |
ID of the activity that was executing when the entity was created, 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 entity"s 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 |
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 |
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) |
| From Entity | Link | Description | Implementation Technique | Required |
|---|---|---|---|---|
| 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 |
| Link | To Entity | Description | Implementation Technique | Required |
|---|---|---|---|---|
| Borehole | Borehole | The borehole in which the checkshot was acquired or is attributed to. | Cascade | 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 |
| Raw_Checkshot_Survey | Checkshot_Survey | The raw checkshot survey from which a processed survey is computed, if available. | Nullify | 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 |
| Velocity_Set | Velocity_Set | _ | Cascade | No |
| Original_Deviation_Survey | Deviation_Survey | The original deviation survey used for processing the checkshot survey. | Nullify | No |
| Depth_Vertical_Reference | Coordinate_System | The coordinate system in which the checkshot depth datum is defined as the vertical reference. | Restrict | Yes |
| Velocity_Source | R_Velocity_Source | _ | Restrict | No |
| Area_Of_Validity | Area | _ | Control | No |
| Value_Property | R_Property | _ | Restrict | No |
| Logging_Activity | Logging_Activity | The logging activity corresponding to the checkshot acquisition and processing. | Nullify | No |