11.6.4.7 - MWD
11.6.4.7.1 - MWD Config
The MWD Probe Config tool allows the user to build the M/LWD probe string inside the BHA. Well Seeker will then combine this information with the BHA details to calculate the sensor offsets. The Probe Config requires the individual probe data to be present in the Probe Catalog (see MWD Probes).
If string templates have been defined in the Probe Catalog, the user can select one using the dropdown in the Probe Config section.
If no templates are available, you will need to build the string manually. The probes entered into the Probe Catalog are displayed in the Catalogsection. Use the Add and Remove buttons to add probes from the Catalog to the probe string. Use the Move Up and Move Down buttons to re-arrange the order.
Note: If a probe has the always on top or bottom cell checked then you will not be able to move this using the Move Up / Down buttons.
Note: Bit direction is down in the probe string, meaning that the bottom of the template should be the probe closest to the bit.
For each probe added to the probe string, enter a serial number and a version number. If you entered the details of the probes into the Inventory dialog, then the serial numbers will be available in dropdown boxes.
In the BHA section, fill in additional details for the probe string. Fields highlighted in green are editable.
Probe Length: The total length of the probes in the Probe Config section. This is automatically calculated and is displayed in the selected length unit.
Carrier Length: The length of the component above the MWD/LWD component, if the string is using a bottom mounted transmitter. If the string is using a top mounted transmitter, it will show the length of the component below the MWD/LWD component.
UBHO Pin to Set Screw: If the string is using a bottom mounted transmitter, this is the distance between the UBHO pin end and the set screw. The software assumes that the end of the last probe is sitting on the set screw. If the string is using a top mounted transmitter, this is the distance between the UBHO pin end and the anchor point on the transmitter.
UBHO Box to Set Screw: The difference between the pin to set screw value and the length of the UBHO / Transmitter Sub.
Bit to UBHO: The distance between the bit and the pin end of the UBHO.
Insertion gear: The distance between the top of the probe string and the end of the carrier component, and represents how much space you have left in your carrier. If this is a negative number, it means the probe string is sticking out of the end of the carrier.
The rest of the inputs in this section do not have any effect on the sensor offsets, but can appear in reports:
Pulser type: Enter a description for the pulser type (e.g. positive pulse).
Helix type: The helix material.
MWD collar type: Choose from either Slick or Flex.
Telemetry Type: Choose from either MP (Mud Pulse), EM, Dual or Wired Pipe
Fin Size: Enter a size for the probe centralizing fins.
Stickup: Enter a stickup length for the MWD.
Gamma Correction: Enter the amount of gamma correction, if applicable.
Retrievable: Select whether the probe string is retrievable or not.
The Sensor Offsets section displays the sensor offsets. The sensors displayed here depend on the types of probes selected in the Probe Config section. The offset values are calculated using the probe length and sensor distance from bottom values entered in the probe catalog, along with the lengths entered in the Drill String Editor for the specific BHA. When you are finished, click on the Apply button to save your changes, and then close the dialog. The sensor offset values will be sent to the MWD/LWD component in your drill string.
Access the MWD Reporting Guide for more information.
11.6.4.7.2 - Surface System
This dialog allows the user to enter the serial numbers for the MWD surface equipment at the rig site. Details entered here are applied to all BHAs for the well, so that the user does not need to enter their information multiple times. If surface system components have been entered into the Inventory, they will be available here as dropdowns. If not, their serial numbers can be entered manually.
11.6.4.7.3 - NM Spacing
This feature allows the user to predict the amount of non-magnetic material required above and below the directional sensor to keep interference from the drill string within a user definable tolerance for uncorrected magnetic surveys. It can also evaluate whether the BHA meets these requirements.
To run the calculation, the following inputs are required:
A completed BHA in the Drill String Editor. This BHA must include:
An MWD/LWD component, with the directional sensor offset entered into the component properties / calculated within the MWD Config dialog.
The non-mag checkbox checked for all non-magnetic components.
Lengths and OD values entered for every component.
Geomagnetic values entered and marked as active in the Magnetics section of the Actual Wellbore Properties dialog for the well.
The Co-ordinate Reference System selected in the Field Properties dialog.
Select Grid or True for the north reference in the Facility Properties dialog.
Enter a well location in the Well Properties dialog.
A survey or principal plan covering the desired depth interval.
In the Settings section, enter the depth interval of the BHA run in the Depth In/Out fields. If you wish to use your principal plan instead of your surveys, toggle the Use Wellplan option. In the Max Azi Errorfield, set your maximum acceptable error in the raw azimuth measurements. The default is 0.5.
The Pole Strengths section displays the pole strength in mWb of the components below (P1) and above (P2) the non-magnetic collars. This is based on their component type and OD. You can manually override these values by toggling the Auto option off.
For each survey/plan station, the table displays the following results.
MD: The measured depth of the survey/plan station.
INC: The inclination of the survey/plan station.
AZI (GRID/MAG): The azimuth of the survey/plan station, referenced to grid north and magnetic north, respectively.
AZI Err: The estimated error in the azimuth readings due to axial magnetic interference from the steel components in the BHA. This column will be colour coded depending on the Max Azi Error limit that you set. Green means the error is below the acceptable limit, orange means it violates the limit by a small margin, and red means it violates the limit by a large margin.
Dip/BTotal Err: The estimated error in the dip and field strength measured by the directional sensor, due to axial magnetic interference.
Req NM Above/Below: An estimation of the length of non-magnetic collars that would be needed above/below the directional sensor, in order to reduce axial magnetic interference enough to get the Azi Error below the Max Azi Error limit.
If any station violates the Max Azi Error limit, the calculator will conclude that there is not enough non-magnetic spacing. It will also report the largest Req NM Above/Below value and compare it to the actual lengths of non-magnetic collars in the BHA.
The user can save their changes by clicking on the Save icon and print their results using the Print icon.
11.6.4.7.4 - Pressure Drop
The pressure drop calculator tool can be used to estimate the pressure drop across the transmitter.
Selected: Poppet only. Select a row and then click on apply. The inputs and results from the selected row will be added to the component properties of the MWD/LWD component.
Type: Choose either Poppet or Restrictor. This will affect the input and output columns available.
Orifice ID: Poppet only. Select the size of the orifice in inches from the dropdown.
Poppet OD: Poppet only. Select the size of the poppet in inches from the dropdown.
Restrictor Size: Restrictor only. Enter the restrictor size in 32nds of an inch – the same as a bit jet.
Flow Rate: Enter the drilling fluid flow rate during the BHA run.
Mud Weight: Enter the mud weight for the BHA run.
Depth: Poppet only. Enter a measured depth value. This is used to calculate the surface amplitude result.
Pulse Width: Poppet only. Enter the pulse time in seconds.
Pressure Drop: The calculated pressure drop across the poppet/restrictor based on the above inputs.
Surface Amplitude: Poppet only. The estimated amplitude of the pulse when it reaches surface. Requires a value entered into the Depth field.
Error: If any required inputs are missing or have invalid values, an error message will appear in this column.
Last updated
Was this helpful?