6.0 – Drill String, Well Geometry and Fluids Tab
Figure 127: Drill string, Well Geometry and Fluids Tab
Figure 128: Project name & description
The project name and the project description can be entered in the edit boxes at the top of the main dialog. These are used in Chart titles and on the Reports
Figure 129: Drill string grid
This grid allows the user to enter the details of the drill string, which is used in all calculation modules. Different types of assembly can be modelled, and data entry is identical for each.
New lines can be added to the grid by clicking on the insert above and below buttons at the bottom of the grid or by pressing the space bar. The insert functions can also be accessed from the context menu by right clicking on the grid. Components can also be moved up and down unless the component is the bit. Rows can be deleted by clicking the delete button or by pressing the backspace key. Multiple rows can be deleted by highlighting multiple rows and pressing the delete button.
Data can be copied and pasted into the grid by using the standard copy and paste methods from the clipboard.
The length of the last component does not have to be specified exactly and the program adjusts its length depending on the calculation depth. If for instance the last item in the BHA is drill pipe just enter 9.9 for its length regardless of the actual length.
The following describes what the various columns in the grid do.
Description: A description of the component entered, this is only used in the generation of reports and plays no part in any of the calculations
OD: The outer diameter of the component in inches
ID: The inside diameter of the component in inches
TJ OD: If the component has a tool joint (such as drill pipe) enter the OD in inches in to this column. If the “Include TJ in calculations” menu option is turned off this column will be disabled.
TJ ID: If the component has a tool joint (such as drill pipe) enter the ID in inches in to this column. If the “Include TJ in calculations” menu option is turned off this column will be disabled.
Weight: This is the weight per unit length of the component, this is either calculated automatically based on the OD / ID of the component or can be entered manually by the user if the “Auto Calculate Weight” option is turned off. This is used for torque and drag calculations as well as SAG calculations.
Component: Select the component type from the drop-down list. The type of component that is selected will determine the properties displayed in the lower components grid. The following is a list of the components available, and a description of their properties can be viewed in Appendix E - Component Details.
- Hole Opener / Under Reamer
- Circ Sub
- Cross Over (X/O)
- RSS – Rotary Steerable system
- MWD / LWD
- Drill Collar
- Drill Pipe / HWDP
- Casing / Tubing
Length: The length of the component in the system units
Total lengths: The cumulative length of the drill string components up to that point. This is automatically calculated.
Non-Magnetic: Is the component steel of non-mag material. This is used for the magnetic interference calculations.
Figure 130: Well geometry
This section allows the user to define the well construction. The section type is selected from the combo box in the type column and the depth is entered in the MD column. The TVD is interpolated from the actual survey listing and if the depth cannot be found the well plan listing is searched. If no survey data has been entered the cell will remain blank. The TVD is not used in any of the calculations and is just displayed for reference.
The ID of the section in inches is entered in the ID column, and the OD is entered in the OD column. ID and OD’s must get progressively smaller and MDs must get progressively deeper. When Open Hole is selected, the OD cell will automatically populate with the same value entered in the ID cell.
Rows can be inserted using the buttons or the context menu. Backspace and the spacebar keys delete and insert rows respectively. A list of the hole section types can be found below.
- Open Hole – This must always be the last item in the geometry list
- Casing – Casing can be positioned below a riser, open water, or an air gap but must be above a liner or open hole. Multiple casing sections can be added to represent a tapered casing string.
- Liner – Must be positioned below casing and above open hole
- Air Gap – Must be the first item entered and if this is detected, riserless drilling mode is enabled. The next item must be open water
- Open Water – Must be below air gap and the second item, used for riserless drilling mode
- Riser – must be the first item entered
Figure 131: Fluid Properties
This section of the main tab allows all the mud properties to be specified. The mud properties are used for all calculation modules.
- Mud weight – Mud density in the units specified
- PV – Mud plastic viscosity. Only used if Bingham plastic hydraulics model is selected
- YP – Mud yield point. Only used if Bingham Plastic hydraulics model is selected
- Cuttings Density – The density of the cuttings in the mud units specified, used in the hole cleaning calculations of the hydraulics module. Default is 21.7ppg
- Cuttings Diameter – Diameter of the cuttings in inches used for the hole cleaning calculations in the hydraulics module. Default is 0.125 inches
- Cuttings Thickness – Thickness of the cuttings in inches used for the hole cleaning calculations in the hydraulics module. Default is 0.125 inches
- Mud Rheology – The Fann dial readings of the drilling fluid, used for all hydraulics models except Bingham Plastic. Included in the rheology section are the N and k values, which represent the Flow Index (N) and the Consistency Index (k). These cells are populated automatically based on the input PV & YP values. If no PV & YP values are input, the 600 & 300 values are used to generate the values in these cells.
- Additional fluids – Allows the user to simulate pumping pills and sweeps. Enter the volume and the density of the fluid and this will be included in the hydraulics calculation. The program effectively calculates a new mud weight for running the calculations based on the additional fluid being added to the system. Multiple fluids can be entered. The cementing module provides more detailed outputs for users interested in modelling pills and sweeps.
- Add Fluid – This radio button adds the populated fluid properties data into a “New Fluid” line in the Fluid Library. When selected, this will open the Fluid Library dialogue and the user can then rename the fluid appropriately and where required add additional information.
- Calculate N & K – Allows the user to manually enter the N & k values. This overrides any PV, YP and Rheology data entered.
- Fluid Library – This radio button opens the fluid library
Figure 132: Fluid Library
The fluid library comes with the above fluids as part of the install. These basic fluids can be edited or deleted and there is no limit to the number of new fluids which can be added. Any fluid from the library can be assigned by selecting it from the drop-down menu in the fluid properties dialogue.
New fluids are saved to a file located in the Engineering folder called Def_fluids.txt. It should be noted that this file will be overwritten if the program is reinstalled for any reason, so if the user has a large fluids library, this should be backed up before removing and reinstalling the software.
- 10 Sec Gel – 10 Sec Gel strength of the fluid. Not used in any calculations.
- 10 Min Gel – 10 minute Gel strength of the fluid. Not used in any calculations.
- Vis – Viscosity of the fluid. Not used in any calculations.
- Temp – Temperature of the fluid. Not used in any calculations.
- Add New – Creates a blank row allowing the user to add a new fluid
- Edit – Allows the user to edit which ever fluid they have selected
- Apply – Saves any changes made
- Reset to Default – Resets the Library back to its default values. This will delete any new fluids added since the initial install.
- Delete – Deletes whichever fluid is selected
- Shear Stress vs Shear Rate Chart – This chart plots the selected fluids 3, 6, 100, 200, 300 and 600 rpm viscometer readings and presents it alongside the Bingham, Power Law, Herschel Bulkley and Robertson Stiff model lines. This can be used as a guide for selecting the best hydraulic model for a specific fluid.
Figure 133: Well Schematic
The well Schematic gives a visual representation of information populated in the Well Geometry section of the main tab. If the user is viewing the program on a large enough screen, this schematic can be found at the right-hand side regardless of which tab is being viewed.
If the program is being viewed on a smaller screen e.g. on a laptop, to maximise space, the schematic will be hidden. It can be viewed at any time though by selecting Tools – Well Schematic from the top menu.