# Linear Borehole Oriented Core

**NOTE**: The **Linear Borehole Oriented Core** Traverse type in **Dips** is exactly equivalent to the **Borehole** Traverse type in **Dips** version 6 and earlier. Only the name has been changed for consistency with the new curved borehole Traverse type names in **Dips**.

The **Linear BH Oriented Core** Traverse Type should be used when you have **oriented core** taken from a **linear** **borehole** (i.e., a borehole which is assumed to have a constant Trend / Plunge orientation for the length of the borehole). If the mapping has been conducted on core recovered from a **linear borehole**, then *three *orientations are required in the Traverse Information dialog to define the **Linear BH Oriented Core** Traverse:

000; 000; 000 (Orient 1 / Orient 2 / Orient 3)

If you have oriented core from a non-linear (curved) borehole which has curvature defined by a survey file, then you should use the Curved BH Oriented Core Traverse type rather than the **Linear BH Oriented Core** option.

## Traverse ID

For a **Linear BH Oriented Core** Traverse, the default Traverse ID will have an "LBH-OC" prefix (e.g. LBH-OC1, LBH-OC2, ...) when you initially add/create Traverses. After adding Traverses you can change the default ID values to any numeric or alpha-numeric values.

## Data Format

For a **Linear Borehole Oriented Core** Traverse, the Data Format is always **Alpha / Beta**, which refers to the local angles **Alpha **and **Beta **for discontinuities logged on oriented core.

In the **Dips** Grid Data view you must enter **Alpha / Beta** values in the Orientation Columns for Linear BH Oriented Core Traverses. This *overrides *the Global Orientation Format, which is not applicable for Traverses which use oriented core. See the oriented core data topic for the definitions of **Alpha / Beta**.

## Traverse Format

The Traverse Format for a **Linear BH Oriented Core** Traverse requires *three *values: **Orient 1/2/3** as described below.

*Example of Traverse Information dialog with two Linear BH Oriented Core Traverses*

### ORIENT 1

**Orient 1** is the angle from the top of core to the reference line (measured clockwise looking in the down core direction). Use **Orient 1 = 0** if the borehole is vertical.

The **Orient 1 **value entered in the **Traverse Information **dialog for a borehole Traverse, is required because the **Beta **angle measured for each discontinuity on the core, must be measured with respect to some reference line along the length of the core.

See the Borehole Orientation Data Pairs topic for more info.

If the reference line is the *top *of the core (i.e., a line along the physical top of the core), then **Orient 1 = 0**. If the reference line is along the *bottom *of the core, then **Orient 1 = 180 **degrees. These are the most common situations. However, Dips allows the reference line to be located at any position with respect to the top of the core, hence an “arbitrary” value can be entered, if the reference line is at some arbitrary position (e.g., 45 degrees from the top line of the core).

The **Orient 1** value serves to orient the rotational position of the core, with respect to the borehole. Without the reference line, you do not know how the core was positioned with respect to the borehole, therefore this is always a required input for oriented core analysis.

**NOTE**: For a vertical borehole, there is no longer a “top” or “bottom” of core, therefore you should enter **Orient 1 = 0**, and the **Orient 3** value is used to determine the position of the reference line. As stated in the help for **Orient 3**: For a vertical borehole, use the clockwise angle from true north to the reference line, looking along the direction of borehole advance.

### ORIENT 2

**Orient 2** is the inclination of the borehole axis from the zenith. Use Orient 2 = 0 for a borehole oriented vertically upwards, and Orient 2 = 180 if the borehole is oriented vertically downwards.

### ORIENT 3

**Orient 3** is the azimuth of the borehole measured from true north. For a vertical borehole, use the clockwise angle from true north to the reference line, looking along the direction of borehole advance.

For a vertical borehole, the **Orient 3** value serves to define both **Orient 1** and **Orient 3**.

For a vertical borehole, **Orient 1**, as defined in **Dips**, cannot technically be defined because there is no "top" of core, since the core is vertical. That is, there is no "top" line from which to measure an angle to the reference line. So you should simply enter **Orient 1 = 0** since it is not actually used.

**Orient 3** serves both purposes of defining the azimuth direction, and orienting the core within the borehole, by defining the orientation of the **Reference Line** on the core, with respect to north. Combined with the fact that the hole is vertical, that gives you all the information you need to correctly orient the core within the borehole.

For a vertical borehole, **Orient 2** is either **0** or **180** degrees, according to whether the borehole was drilled downwards ( **Orient 2 = 180**) or upwards ( **Orient 2 = 0**).