Using Targets
To use targets in well planning, the planner must have the location and geometry of any drilling and geological targets defined within the Target Editor. These targets must be assigned to the current wellpath before they can be used. Most of the planning methods enable you to select a target to which to plan. By default, the planning methods designs to the aiming point of the target, though an Adjust button is usually available that allows you to manually move the aiming point. If a target is not defined, the well planner can usually enter the location as a point in space: TVD, Northing and Easting from the local
coordinate origin.
Plans designs that are designed to target locations remain linked to those targets. If a target location is changed, all linked plans are updated automatically. Therefore, the plan editor and target editors can be used concurrently while directional well planning.
In the COMPASS™ software, a target is a subsurface location (TVD, N, or E) with an assigned geometry and orientation that may be used for planning or wellpath monitoring.
After they are created, targets can be used by the Survey and Planning modules, can appear on most of the available graphics, and can be referenced in planning and survey reports.
Target Geometry
Each target can have a shape defined about its location. A target can be geometric (either a point, rectangle, circle, or ellipse) or nongeometric (defined as a polygon with any number of points).
COMPASS™ Software Release 5000.1.7 Training Manual 5-3 Chapter 5: Planning Module
The following graphic depicts geometric and polygonal targets:
Each target has an aiming point, which is the location that the Plan Editor methods aim toward. For geometric targets, the aiming point defaults to the geometric center. However, this aiming point can be offset laterally and vertically from the geometric center by using X and Y offsets and thickness up and down. Thickness enables a planar depth to be assigned to the geometrical target. Polygonal targets can have variable thicknesses defined, which enables wedge or drillers cones to be modeled. All targets can be rotated about the aiming point and inclined from the horizontal along any azimuth; this enables a target to model geologic dip and strike.
Target geometry is discussed in more detail later in this chapter.
Accessing the Target Editor
Several ways to access the Target Editor include:
• selecting File > Properties > Project > Targets.
• selecting a project or wellbore in the Well Explorer, and then double-click the target entry in the Data Viewer.
• Click the icon on the toolbar.
Chapter 5: Planning Module
Using the Target Editor
Click the Project icon to view all targets for the project.
Click the Wellbore icon to view only the wellbore targets.
Select the check box associated with a target to indicate the target is a Wellbore target.
In the Target Properties section, you can specify the location, shape, size, and orientation of the target.
Local coordinates are from the local coordinate origin.
Map coordinates are based on the grid system specified by selecting File > Properties > Project > Properties > Map Info.
Polar coordinates are a distance and azimuth from the local center.
Target Viewer.
COMPASS™ Software Release 5000.1.7 Training Manual 5-5 Chapter 5: Planning Module
Defining the Target Geometry
Use the Geometry tab to enter information on the target’s shape. A target can be a simple point location, a radius about an aiming point, a box or rectangular shape to define lateral tolerance, an ellipse, or a complicated polygonal target with any kind of irregular geometry.
The Geometry tab in the Target Editor is used to define the shape for the selected target or for a new target. When you select a shape on this tab, appropriate entry fields are enabled so that you can define the shape in detail.
Target shapes can be one of a number of pre-defined shapes, including:
• Circle – circle, semicircle, or pie slice
• Ellipse – ellipse or a semi-ellipse
• Rectangle – square or rectangle
• Polygon – user-defined shape
Circular Targets
The following graphic depicts the Circular Target Editor window:
This window enables you to enter a circular target or, by giving the circle height and a dip angle, define a cylinder.
Select the desired of the target from the plan-to point by entering X (local East) and Y (local North) offset.
Start and End Angles enables
“pie-shapes” to be defined for circular and elliptical targets.
For a full circle shape, use zero for the start and end angles.
Type a value in
minus the inclination of the target. This is the direction a ball would roll if placed in the formation bedding plane.
Chapter 5: Planning Module
Elliptical Targets
The following graphic depicts the Elliptical Target Editor window.
Rectangular Target
The following graphic depicts the Rectangular Target Editor window.
Rotation angle enables the target to be turned relative to Site North. Target rotation is about the aiming point.
Thickness Up and Down enable the aiming point to be offset vertically within
Type the dip angle you want to be on at the target. This is 90° minus the inclination of the target. Type the azimuth (direction from local north) of the down dip direction. This is the direction a ball would roll if placed in the formation bedding plane. This is not the
COMPASS™ Software Release 5000.1.7 Training Manual 5-7 Chapter 5: Planning Module
Polygonal Targets
The following graphic depicts the Polygonal Target Editor window:
A polygon can have any number of points defined on it using the points defined using the grid (shown above).
Defining Equivalent Formation Thickness
Target up and down thicknesses are used to define equivalent formation thickness.
This method is useful because you can define the aiming point at a given depth below the formation top. For example, if you have a dipping formation that is 30 m thick but want to drill down dip 5 m below the formation top, you define the aiming point as 5 m up, 25 m down. This method is applicable to all
target geometries.
Each point on a polygon may be given its own name or label.
Wedge targets may be defined by changing thickness Up and Down for each polygon point.
Enter the orientation of the target from local north. The orientation is zero when aligned to local north and increases clockwise. If you define a dip angle, this is the down dip direction of the equivalent formation.
Chapter 5: Planning Module
Three methods are available to define points on a polygon:
• X and Y – Enter local x- and y-coordinates from the target aiming point to define a polygon shape. By default, the last point is joined to the first to close the polygon. The Y dimension is parallel to the local N/S, if no orientation is applied.
• Map E and Map N – Alternatively, enter the map coordinates of the target as given by the geologists. The local x- and y-coordinates are computed based on the target center. If the target center is moved, these periphery points move as well.
• Well Viewer – Define Polygonal Targets – With the target created, click the Define Polygonal Targets icon ( ). The viewer displays a plan view of the target, on which you can use the mouse to click each point on the polygon. Depress the icon after all points are clicked, and the Target Editor will join up the first and last points.
For help on other target geometry, see the online help.
Defining Drilling Targets
If the geologist gives you the dimensions for a target and you drill to it using MWD, you may hit it near the edge. When the path is later surveyed by using a gyro, quite often the wellbore ends up outside the target.
To prevent this situation, the planners should reduce the geologists target by the expected survey error radius to be found by drilling with MWD (which might be tied to a gyro at the previous casing). The reduced target is known as a drilling target. It is a zone within the geological targets that, when drilled within and monitored by using survey instruments with inaccuracies, has a good chance of hitting the geological target boundary.
The drilling target tool creates a new target that has been reduced in size from the original by the survey errors at the target depth. It requires a target that is big enough to fit the survey errors and a survey program that penetrates the target.
You should create a survey program from a plan with the survey tools for the situation when drilling the final section of the hole to the target (that is, gyro in intermediate casing and MWD in open hole).
COMPASS™ Software Release 5000.1.7 Training Manual 5-9 Chapter 5: Planning Module
The drilling target tool may be used to design a cost-effective survey program applied to the given geological target sizes.
Select Design
Use this tree control to select the wellbore design that contains the survey program, and hence the survey errors, you want to use to compute the drilling target.
Confidence Level
Enter the confidence level (1% - 99%) required to hit the target using the survey errors from the selected design.
Create Drilling Target
After a design has been selected and a confidence level entered, click this button to create the drilling target.
Delete Drilling Target
Click this button to delete a drilling target.
View Points in NotePad
Click this button to display the computed target points in text format.
For an explanation of the differences between geologist’s and driller’s targets, see the online help.
Using the Target Viewer
The target view displays the currently selected target, which you can toggle as a Section, Plan, or 3D view with the usual 3D tools available.
You can use the Target Viewer to define polygonal targets and to change the landing point for directional well planning calculations. For more information about using the Target Viewer for designing polygonal targets, see the online help.
Chapter 5: Planning Module
Target Landing Point Adjust
When planning or doing project ahead, the Target Viewer has another use. If a target is selected from a pull-down list, click Adjust to adjust the landing point. The Target view is invoked in Adjust mode. Click anywhere on the Section or Plan view to adjust the landing point. The plan or projection immediately updates the calculations using this new point. The target location is not changed.
To change the landing point for planning calculation:
The landing point or aiming point is defined in the Target Editor.
1. Create a new plan or open an existing plan.
2. Select a planning method that lets you select a target (for example, a 2D slant well).
3. In the Plan Editor, select a target.
4. Click Adjust.
5. In the Target View window, move the cursor to the coordinates for which you want to aim and click MB1.
6. The plan is automatically recalculated to hit that point.
• To change the horizontal location, click the Plan view icon ( ).
• To change the vertical location, click the Section view icon ( ).
• You can also type in the landing point coordinates and click Set.
• To revert to the original coordinates, click Reset.
COMPASS™ Software Release 5000.1.7 Training Manual 5-11 Chapter 5: Planning Module