10.0 - Cementing Tab
Figure 152: Cementing Tab
This section displays the various volumes, capacities and displacements of the drill string and the annulus.
The top of this section details the different capacities of the drill string components. These components are taken directly from the drill string entered in the drill string tab, and the capacities are automatically calculated based on the dimensions (OD & ID) associated with these components. The annular capacities are detailed for the components, based on each of the lines entered in the Well Geometry section of the drill string tab. NOTE: A String Depth MUST be entered for this section to display correctly.
Figure 153: Volumes
The middle part of this section shows the various capacities, volumes and displacements for the well. NOTE: A String Depth MUST be entered for this section to display correctly.
The lower part of this section is the most important as the inputs here affect the entire cementing calculations.
- String Depth: Depth of the string when performing the cement job. The calculation will not run without a value entered here.
- Displacement Type: Select Open Ended or Close Ended. This affects the Displacement and Total Displacement calculated values.
- Flow Rate: Flow rate of cement job. This is used to calculate the Top Down, Bottoms Up and Full Circulation values. This input is not required to run the cementing calculation, as the pump rate for this is entered in the pumping schedule section.
- Pump Output: Volume pumped per stroke. Pump efficiency should be factored into this input i.e. if the book output is 0.1bbl/stroke and the pump is 95% efficient, then output should be entered as 0.095bbl/stroke. This input is essential as it is required for calculating the number of strokes in the Pumping Schedule section.
- Stroke Rate: This cell auto calculates based on the values entered for flow rate and pump output.
- Hydraulics Model: Select from Bingham, Power Law, Herschel Bulkley or Robertson Stiff. This affects the calculated Annular Pressure, Pump Pressure and ECD values in the Cementing Results dialog.
This section allows the user to quickly calculate the volumes required for the cementing operation.
Row 1 should contain the first fluid to be pumped and the user can enter the required top, and the bottom will be automatically populated. The top and bottom depths of the fluid represent where they will be in the Annulus at the end of the cementing operations. The user can then enter as many additional lines as required. It should be noted that the bottom depth of the fluid in the last row will always be equal to the String Depth value input in the Volumes section.
Figure 154: Cement Volumes
The user can also enter the desired excess and the volume column will update automatically to reflect this excess percentage.
Once the Cement Volumes and Cement Job Calculation sections have been input, the user can select Create, which will populate the Pumping Schedule table, with the description and calculated volumes from the Cement Volumes section. Note that this also takes into account the data input in the Cement Job Calculation section. It is also possible to complete this section manually.
If the Include Spacer box is checked and then Create is selected, row one of the table will be created for a spacer, but the volume cell will need to be populated manually by the user. If the user has included a spacer in the cement volumes section, then the include spacer box should not be checked.
The Use Rheometer Readings check box toggles the Pumping Schedule table between PV, YP and 600 – 3 rpm dial reading inputs.
The user should fill in the Description, Volume, Wt, Pump Rate, and rheology values for each row. These inputs affect the calculated Annular Pressure, Pump Pressure and ECD values in the Cementing Results dialog.
Figure 155: Pumping Schedule
For conventional cement jobs the user should enter the Shoe – Float Distance. The shoe track capacity will be automatically calculated.
If cementing with a stinger, the user should check the Cementing with inner string box and enter the Description, OD, ID and Length of the stinger string. The capacity and total capacity of the inner string will be automatically calculated.
Figure 156: Cement Job Calculation
Once the cementing tab has been completed, selecting Calculate opens the Cementing Results Dialog.
Figure 157: Cementing Results Dialog
The Cementing Results dialog displays all the information and results relevant to the cementing module. By utilising the scroll bar at the bottom of the dialog the user can view the three charts at different stages of the cement job.
Figure 158: Cementing Schematic
This is a visual representation of the well geometry, string and fluids at a given stage in the cement job, dictated by the position selected on the scroll bar. The values used to generate this schematic (MD, Component OD & ID’s and well geometry OD & ID’s) are taken from the values entered in the Drill String, Well Geometry and Fluids Tab. The fluid labels can be toggled on or off by selecting Chart Options and checking or unchecking Show Schematic Fluid Labels.
- Changes in well geometry are marked by a label and dashed line.
- Areas out with the fluid flow path are white.
- Sea water is dark blue
- Drilling mud is brown.
- Spacer is light blue.
- Lead cement is dark grey.
- Tail cement is light grey.
- Displacement fluid is a variable colour.
Figure 159: Pumping Schedule Chart
The Pumping Schedule chart depicts:
- The annular pressure at the string depth entered in the volumes section
- The equivalent circulating density (ECD) at the string depth entered in the volumes section
- The pump pressure at surface at a given stage in the cement job
- The Flow Rate
All the above outputs are dictated by the position selected on the scroll bar.
The X-axis can be toggled to display either Elapsed Time or Strokes by selecting Chart Options and checking or unchecking X Axis – Strokes.
Figure 160: Cementing Results Dialog Scroll Bar
The position of the slider on the scroll bar dictates the stage of the cement job depicted on the Cementing Schematic, Pumping Schedule and ECD Snapshot. The user can click the play button for the slider to commence movement at a specific speed. This speed can be adjusted using the + and – keys to speed up and slow down the slider progression respectively. The user can then select the pause button to stop the slider at any point. The slider can also be manually dragged to any point in the scroll bar by the user.
Figure 161: Cementing ECD Snapshot Chart
The ECD Snapshot chart depicts the equivalent circulating density and the annular velocity, across all depths from surface to the string depth, at a given stage in the cement job, dictated by the position selected on the scroll bar.
The right-hand side of the chart shows the flow regime across all depths from surface to the string depth, at a given stage in the cement job, dictated by the position selected on the scroll bar. Red is Laminar Flow and Green is Turbulent.
Additionally, markers display the respective depths of the top of the various fluids in the annulus and any changes in the well geometry.
Within the Cementing Results dialog, the user can output the following via the file menu:
Figure 162: Cementing Results File Menu
File > Print PDF Report. This generates a report which can be saved to pdf format.
Figure 163: Cementing PDF Report Layout
The report includes all the relevant data used in the cementing calculation and the charts displayed within the Cementing Results dialog, as they appeared when the report was created.
File > Print Excel Report. This generates a report which can be saved to excel format.
Figure 164: Cementing Excel Report Layout
The report includes all the relevant data used in the cementing calculation and the charts displayed within the Cementing Results dialog, as they appeared when the report was created. These charts are allocated their own sheet within the excel document.
This option allows the user to export the data used to generate the Pumping Schedule and ECD Snapshot Charts, in Excel format.
Figure 165: Cementing Chart Options Menu
X-Axis – Strokes – This option allows the user to switch between Strokes and Elapsed Time as the units for the X-axis of the Pumping Schedule Chart in the Cementing Results dialog.
Show Schematic Fluid Labels – This option allows the user to turn the fluid labels on and off in the Cementing Schematic section of the Cementing Results dialog.
Annular Contact Time Chart – This option opens the Annular Contact Time Chart. This chart shows the length of time any of the individual fluids in the pumping schedule are in contact with the annulus at any given depth.
Figure 166: Annular Contact Time Chart