During a leak off test, this program will read and record the pressure changes realtime and, at the end of the test, will calculate the fracture pressure and equivalent mudweight. By default, the casing pressure sensor will be the one monitored for pressure readings, so you should ensure that the test is being conducted on the same manifold as your sensor.
Required information: -
Sampling interval i.e. how often data will be recorded. Input by the user, typically 5 seconds.
TVD Taken from realtime system hole depth - this may need to be edited for
the depth of the test.
Mud Density Taken from the realtime system - this may need to be edited to show the value determined by the mud engineer and thus the value to be used for calculations.
Mud Pump or Auxiliary pump
Pump number The pump output can then be determined from the pump data file. Volume or Time The parameter that the pressure will be plotted against.
If Mud Pump is selected above, you can select either volume or time so that the pressure will be plotted against either the mud volume pumped or time.
If Auxiliary is selected, you have to select time here, since you will not have a stroke indicator.
Once all the data has been entered, press F3 to start. The program will then start collecting data based on the sample interval selected.
Once the test has finished, press any key to stop the data acquisition. Press F7 to calculate.
The program will determine the maximum pressure recorded, and from that it will calculate the Fracture Gradient in terms of Equivalent Mud Density. Beware that the ‘Fracture Pressure’ quoted is the maximum Applied Pressure recorded during the test, not the actual Fracture Pressure.
8.2 Kick/Kill Program
This program takes data both from the realtime system and from user input. Any data taken from the realtime system can be edited if required.
Page 1 Data
Pump speed and pressure for Slow Circulation Rates. These should be performed regularly by the driller and the mudlogger should update this program every time they are performed. The pump output will be calculated automatically from the pump speed and the output stored in Realtime-Pump Data. Use ‘enter’ to update the calculation.
Pump to use i.e. which pump are they going to use to circulate kill mud. Drillpipe and Annular Capacities Calculated automatically from hole and pipe profiles
Original Mudweight Taken from the realtime system.
Trip Margin Enter the required pressure if a certain overbalance on the kill mudweight is required.
Down Strokes and Lag Strokes Calculated from the current profiles, but they will only be updated if the rig is circulating and the system is registering pump strokes.
Since, when running this program, the well is likely to be shut in, you may have to enter the correct strokes manually.
Casing Burst Pressure Obtain from the drilling engineer
Depth of Last Casing Shoe Taken from the hole profile but remember that this will be measured depth. If the well is deviated, the True Vertical Depth should be entered here.
Formation Fracture Gradient Manually entered from the last Leak Off or Formation Integrity Test.
Page 2 Data
Shut in Pressures Drillpipe and Casing - these will be read from the realtime system, but should be confirmed with the driller when the pressures have stabilized.
Pit Volume Increase i.e. the pit gain due to the kick. Remember to subtract surface line run off, if applicable.
Pit Volume Total This should be the total volume of the pits that will be used to make up and circulate the kill mud. This volume is required to
determine how much barite is required to increase the mudweight.
Total Vertical Depth Taken from the system (hole depth) but it will have to be edited if the kick does not occur at the bottom of the hole.
Kill Method 1 for Drillers, 2 for Wait and Weight, 3 for Concurrent
Stroke/MW increment For the Drillers and Wait and Weight methods, this is the stroke increment for the pressure step down when the kill mud is being circulated to the bit (as the kill mud goes from surface to bit, the pressure should be reduced from the Initial to the Final Circulating Pressure).
For the Concurrent Method, it is the incremental increase in mudweight that should be entered - the program will then determine how many circulations will be required.
Options
F7 to calculate: Initial Circulating Pressure
Kill Mudweight
Final Circulating Pressure
Maximum Allowable Casing Pressure
Total Barite Required
Sacks of Barite to Add
Fluid Invasion Type
Trip Margin Mudweight ie kill mudweight + increment necessary to give the defined pressure overbalance Trip Margin Sacks (of barite)
F3 for Table:
For Driller/Wait and Weight methods, this will be a table of strokes vs pressure for the pressure step down (Initial to Final) as the kill mud is circulated to the bit.
For Concurrent method:- for each circulation required with an incremental increase in the mudweight, the final circulating pressure is shown.
F2 to Print: Prints out the table above