Structure

class wellcad.com.Structure(dispatch)

Structures are picked features (strata, lineations, fractures, breakouts) within a Structure, Lineation or Breakout Log.

Sinusoidal structures (for example factures crossing a borehole) can be partial with only limited visible portions. Lineations are penetrative linear elements within a rock and can be of various origin (mineral lineation, fold axis etc.) Breakouts structures are vertical fractures caused by compression forces on the borehole walls. Their length, aperture and orientation helps to understand the constraints applied to the rock formation.

+-------------------------------------------------+-------------------------------------------------+
|                                                 |                                                 |
|                                                 |                                                 |
|         Full structure with aperture            |      Structure with partial features            |
|                                                 |                                                 |
| 0                    180                     360| 0                    180                     360|
+-------------------------------------------------+-------------------------------------------------+
|                                                 |                                                 |
|         XXXXXXX                                 |         .......                                 |
|      XXX:::::::XXX                              |      ...       ...                              |
|    XX:::::::::::::XX                            |    ..             ..                            |
|   X:::::XXXXXX::::::X                           |   .                 .                           |
|  X:::XXX      XXX::::X                          |  .                   .                          |
| X::XX            XX:::X                         | .                     .                         |
|X::X                X:::X<- depth               X|.                       .<- depth                |
|::X                  X:::X                     X:|                         .                       |
|:X                    X:::X                   X::|                          X                   X  |
|X                      X:::X                 X::X|                           X                 X   |
|                        X:::XX             XX::X |            feature_depth ->XX             XX    |
|                         X::::XXX       XXX:::X  |                              XXX       XXX      |
|                +-        X:::::XXXXXXX::::::X   |                                XXXXXXX          |
|       aperture |           XX:::::::::::::XX    |                                                 |
|                |             XXX:::::::XXX      |                                                 |
|                +-              XXXXXXX          |                                                 |
|                                                 |                                                 |
+-------------------------------------------------+-------------------------------------------------+

 +------------------------------------------------------------+
 |                    Breakout log                            |
 |                                                            |
 |      azimuth                                               |
 |         |                                                  |
 | 0       v                   180                         360|
 +------------------------------------------------------------+
 |                                                            |
 |                                                            |
 |      +++++                          +-         +++++       |
 |      +:::+                          |          +:::+       |
 |      +:::+                          |          +:::+       |
 |       +:::+                         |         +:::+        |
 |       +:::+                         |         +:::+        |
 |       +:::+                         |         +:::+        |
 |        +:::+  <- depth    length -> |        +:::+         |
 |        +:::+                        |        +:::+         |
 |        +:::+                        |        +:::+         |
 |         +:::+                       |       +:::+          |
 |         +:::+                       |       +:::+          |
 |         +:::+                       |       +:::+          |
 |         +++++                       +-      +++++          |
 |                                                            |
 |         |____|                        mirrored breakout    |
 |        aperture                                            |
 |                                                            |
 +------------------------------------------------------------+

 +------------------------------------------------+
 |                    Lineation log               |
 |                                                |
 |        trend                                   |
 |          |                                     |
 | 0        v           180                    360|
 +------------------------------------------------+
 |                                                |
 |                                                |
 |                     *=========*                |
 |        *                             *         |
 |       .\\                           //         |
 |       . \\                         //          |
 |       .  \\                       //           |
 |       .   \\                     //            |
 |       .____\\                   //             |
 |         ^   \\                 //              |
 |         |    *                //               |
 |         |                    //                |
 |     plunge                  //                 |
 |                            //                  |
 |                           //                   |
 |                          *                     |
 |                                                |
 +------------------------------------------------+

Example

>>> log = borehole.log("Structure")
>>> struct = log.structure(0)  # The Structure object at depth index 0
>>> struct.tilt
37.59
>>> struct.get_attribute_value("Type")
'2 - Bed / Lamina'
property aperture

The vertical aperture of the sinusoidal structure in meters or the opening angle of a breakout structure in degrees.

Type:

float

property azimuth

The azimuth angle for a structure in degrees.

Azimuth is the angle of inclination of the structure measured downward from horizontal. Depending on the log type, azimuth has a different meaning:

  • dip direction for planar features (i.e. Structure log).

  • azimuthal position for breakouts and tensile fractures (i.e. Breakout Log).

  • trend for vector like structures (i.e. Lineation Log).

Type:

float

property depth

The depth of the center of a structure object in current depth units.

This is different from feature_depth if part of the structure is not visible.

Type:

float

property eccentricity

Describes the offset between lineation (vector) and the center of the borehole.

The property has a value of 0 for a lineation crossing right through the center of the borehole. Lineation intersecting the borehole off center have an eccentricity between -1 and 1.

Type:

float

property feature_depth

The depth of the centre of the range of all visible parts of a sinusoidal structure in current depth units.

Type:

float

get_attribute_value(attribute_name)

Gets the value from the specified attribute class belonging to the structure object.

Attributes are elements of a key-value map specified by the user.

Parameters:

attribute_name (str) – Name of the attribute class from which to retrieve the code.

Returns:

The code associated with this attribute

Return type:

str

property length

The length of a breakout structure in meters.

Type:

float

set_attribute_value(attribute_name, attribute_value)

Sets the value from the specified attribute class belonging to the structure object.

Parameters:
  • attribute_name (str) – Name of the attribute class from which to modify the code.

  • attribute_value (str) – The code from the above attribute class you would like to assign to the picked feature.

property tilt

The tilt angle for a structure in degrees.

Tilt is measured from the horizontal. It corresponds to the structural dip angle. Depending on the log type, tilt has a different meaning:

  • dip angle for planar features (i.e. Structure log)

  • tilt angle between breakout and borehole axis (i.e. Breakout Log)

  • plunge for vector like structures (i.e. Lineation Log).

Type:

float

property visible_azimuth_ranges

The range of visible azimuths of the item.

If there are partial sinusoidal structures, this property specifies the azimuth ranges where the structure is visible, otherwise it returns an empty string.

Examples

  • stucture entirely visible : ""

  • 1 visible azimuth range : "25.00-189.00"

  • 2 visible azimuth range : "12.00-36.00-100.00-150.00"

Type:

str