8.3.2 - Calculators
8.3.2.1 - Geomagnetics
This option opens the Geomagnetic Calculator dialog, which is a standalone tool that performs the following functions:
Convert latitude and longitude to map co-ordinates and vice versa.
Calculate and print magnetic data based on the co-ordinates entered.
Set the default magnetic model used in Ellipse of Uncertainty (EOU) calculations.
Convert between NAD83 and NAD27 co-ordinates.
In order to use the Geomagnetic Calculator a co-ordinate reference system (CRS), also known as a mapping grid, must be selected from the drop-down menu at the top of the dialog. The “Scale factor” box will then display the scale factor of the selected CRS. Clicking on the Mapping Grid button will open the CRS Editor. See section 8.3.2.2 – Co-ordinate Reference System (CRS) Editor.
Co-ordinates can be entered either as a latitude & longitude or as a map co-ordinate. This is defined by selecting the “Grid North / East” or “Lat / Long” radio button. The grid convergence is displayed in the edit box marked “grid convergence”. This value will be applied when converting between grid north and true north.
Once a CRS has been selected and co-ordinates have been entered, the user can display the location on a map using the Show Map button. Note that this map is generated using Google Maps, which will likely not be using the same CRS as the one selected by the user. This means that the location plotted on the map will not be completely accurate.
Magnetics data can be calculated for the co-ordinates entered by selecting a date and entering an altitude in the “location data” section.
It should be noted that the date selected must be within range of the geo-magnetic model selected or an error will be displayed.
To select the geomagnetic model, open the drop-down menu next to the model edit box and all the models which are currently in the install directory “Magnetics” folder will be displayed. The location for the “Magnetics” folder is C:\Program Files (x86)\Innova Drilling and Intervention\Well Seeker X (x64)\Magnetics.
Well Seeker X comes as standard with the IGRF and WMM magnetic models, however it also supports HDGM, BGGM and mvHD magnetic models. To use BGGM, copy the BGGMXXXX.dat file into the magnetics directory and make sure there is a copy of bggm32_v3_8.dll in the magnetics directory. For HDGM models simply paste the hdgmxxxx.dll into the magnetics directory.
If the Geo Mag converter dialog is open and a new model is added to the magnetics folder, the dialog will have to be closed and reopened before Well Seeker X can see it.
It should be noted that world magnetic model .COF files must start with “WMM” as the first three letters of the filename, IGRF files must start with “IGRF”, BGGM must start with “BGG” and HDGM must start with “HDGM”.
Once the date and model have been selected, the magnetic data will be displayed. The user can export their magnetic data to either PDF or Excel format using the Print button. The Set as Defaultbutton will set the selected magnetic model as the default model when creating a new Actual or Planned Well.
The NAD83 / NAD27 Conversion section can be used to convert map co-ordinates & latitude/longitudes plotted on a NAD83 Datum CRS to their equivalent in a NAD27 Datum CRS, and vice versa. Note: An internet connection is required for this function to work.
To perform a conversion, the user should select a CRS in the Projection details that uses a NAD83 or NAD27 Datum. Then enter their co-ordinates into the Location data section and click on the Convertbutton. The converted nothing, easting, latitude, and longitude results will then be displayed in the results boxes. If there is an error with the conversion, then a message will be displayed in the “Errors” box.
8.3.2.2 - Co-ordinate Reference System (CRS) Editor
The CRS Editor is where the user can create, delete, and edit their available Co-Ordinate Reference Systems. Well Seeker X comes with several of the most common CRS installed by default.
The available CRS are listed on the left-hand side of the window. The user can filter the list by entering a name into the Search box at the top of the window. The CRS Editor is controlled using the toolbar at the top of the window:
Save CRS: Saves any changes made in the CRS Editor.
Add new CRS: Creates a new blank CRS titled ‘New CRS.’
Delete CRS: Deletes the currently selected CRS.
Export CRS: Exports the selected CRS as .json file, allowing it to be sent to other users.
Import CRS: Imports a CRS from a .json file and adds it to the list.
Select CRS: Closes the CRS Editor and sets the currently selected CRS as the one in use in the Field Properties/Geo-mag Calculator.
Edit CRS: Allows the currently selected CRS to be edited. The CRS details on the right of the window will no longer be greyed out and the user can edit each line by left clicking on it.
Parameters highlighted in GREEN are required and affect the output - Care should be taken to enter the data correctly:
Name: This can be anything you want as it has no impact on any of the calculations. In Well Seeker, the naming convention is the System/ and then the Map Projection, and it is recommended that this convention is followed.
Area of use: Description of which part of the earth this CRS references and has no effect on any of the calculations.
Datum: This is just text and does not directly affect any calculations.
System: This is just text and does not directly affect any calculations.
Ellipsoid: The name of the Ellipsoid. This does not have any effect on the output.
SemiMajor Axis (m): This is the Equatorial Radius of the Ellipsoid in metres and is required for the CRS to work.
Semi Major Axis (UOM): This is the equatorial radius of the ellipsoid in the units of measure which the CRS is using and is optional.
Units of Measure: This is a drop-down menu option, and you can choose from 7 options.
Inverse Flattening: Also called ‘1/f’, this is the inverse Flattening of the Ellipsoid and is required for the CRS to work.
Map Projection: This is just text and does not directly affect any calculations.
Projection Type: This is a drop-down menu, and you can choose from 4 options – TM, 1SP (Standard Parallel), 2SP or STEREO.
False Easting: A linear value applied to the origin of the x-coordinates. Usually applied to ensure all x-values are positive.
False Northing: A linear value applied to the origin of the y-coordinates. Usually applied to ensure all y-values are positive.
Latitude of Origin: This should be input as a decimal.
Longitude of Origin: This should be input as a decimal.
Scale Factor: Ratio between measured distance on the map and on the ground.
1st Standard Parallel: This information will be required if you select 1 SP or 2 SP from the Projection Type Drop down menu.
2nd Standard Parallel: This information will be required if you select 2 SP from the Projection Type Drop down menu.
8.3.2.3 - DDI
This option will only be available if user has a Plan or Survey opened. It will open the Directional Difficulty Index (DDI) dialog, that provides a first pass evaluation of the relative difficulty expected when drilling a directional well.
DDI is one of the metrics by which directional drilling performance can be measured. By plotting the planned DDI against the actual DDI, the separation between the two can be used as a metric for directional drilling performance. The smaller the difference the better the directional drilling performance, (it should be noted this is not applicable to wells which are modified while drilling or wells that are geo-steered).
The DDI has also proved useful in other areas of planning. It allows various proposed well paths targeting the same reserves to be ranked in terms of their directional complexity. This is particularly useful in mature assets where a number of candidate wells may be available as side tracking options. By ranking these options, unsuitable host wells may be eliminated. It also ensures that the most cost-effective option from a directional drilling viewpoint is known. This can then be weighed against other influencing factors allowing the most suitable host well to be selected.
For more details relating to this feature refer to IADC/SPE 59196 (The Directional Difficulty Index - A New Approach to Performance Benchmarking)
The DDI dialog will also calculate the tortuosity index of the wellbore, split into vertical (VTI), lateral (LTI) and the total 3D tortuosity (3D TI).
8.3.2.4 - Motor Yield
The Motor Yield calculator can be used by the directional driller to quickly calculate their motor yield from a recorded slide, or to calculate how much sliding is required to achieve the desired dogleg base on a specified motor yield.
To use the motor yield calculator: Enter the slide length, stand length and the dogleg achieved over the course of the stand. The calculator will output the motor yield over the stand.
To use the slide length calculator: Enter the stand length into the motor yield calculator section. Enter a motor yield and the desired dogleg over the course of the stand. The calculator will output how much of the stand needs to be slid, as a raw distance and a % of the stand.
8.3.2.5 - TF Conversion
The Toolface (TF) Conversion dialog allows the user to convert between a gravity toolface and a magnetic one, for a specific survey station. To use the conversion follow these steps:
In the Survey Data section, enter the Inc and Azi of the survey station.
In the Reference Data section, choose whether the survey station azimuth is referenced to grid north or true north. Enter the dip, declination and grid convergence.
In the Toolface Input Data, choose if you are converting from magnetic toolface to gravity toolface, or vice versa. Then enter the original toolface in the Input Toolface.
The converted toolface will be displayed in the Output Toolface field, with the size of the conversion displayed in the Magnetic -> Grav Offset field.
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