DRILLING FLUIDS, VOLUMES,& TRIPPING JOBS
Synopsis:
Drilling fluid plays an important role in any drilling activity. It is the main controlling parameter in well control. Its main function is to control the bottom hole pressure (BHP) and stabilize the borehole. Therefore, it is very important to properly design the mud to avoid any fluid loss or cause formation damage.
This project aims at giving students the opportunity to have a comprehensive idea of the overall activities and the process related to mud use starting from mixing it up to tripping jobs. The product of this project (Excel sheet) can be used as a tool to make any calculation related to the use of mud in any drilling activity in the future. In other words, you will be able to use the Excel sheet in your future jobs if you ever get involved in any drilling activity.
Project Objective:
The aim of this project is to develop an Excel sheet that calculates the following for typical drilling fluid and well configurations:
- Required densities of drilling fluids
- Rheological properties of a given mud
- Volumes of typical wells, pump pressure, output, and strokes,
- Effect of tripping jobs on the hydrostatic pressure.
Project Requirements:
You are expected to take your own mud properties (i.e., measurements made in the lab) and select a typical well configuration as well as the mud pump (use both duplex and triplex pumps) to calculate the following:
1. Average mud weight (ppg) when mixing two densities
2. Required fluid volumes of two unknown fluid densities to obtain desired final volume and density
3. Use any of your lab data to calculate:
a. Plastic viscosity
b. Yield point
4. Amount of barite (100 lb/sx) needed to weight-up the mud
5. Amount of water (bbls) needed to dilute the mud
6. Total volume in the hole when the drillstring is completely out of the hole.
7. Mud volume in the drillstring of a typical well (select your own drillstring sizes)
8. Mud volume in the annulus of a typical well
9. Buoyancy factor
10. Hook load when drillstring is fully submerged in the well.
11. Number of pump strokes from surface to bit
12. Number of pump strokes from bit to surface
13. Total number of pump strokes
14. Total circulation time
15. The drop in mud level for a specified number of stands pulled
a. Dry pull out
b. Wet pull out
16. The corresponding pressure drop for
a. Dry pull out
b. Wet pull out
17. If you are drilling in a field with a the formation pressure gradient of 0.55 psi/ft, indicate in your program if a kick takes place or not depending on the hole depth and mud density. Take a pressure of 150 psi as a safety margin (i.e., BHP + 150 = formation pressure).
Recommendations:
- For calculations 11 - 14, you need to select standard sizes of duplex and triplex pumps and perform the calculations.
- It will be nice if you can draw a schematic diagram of the selected well with the drillistring showing the drop of the mud level, its corresponding pressure drop as well as the bottom hole pressure during tripping jobs.
Project Execution:
You are required to do the following:
1. Search through the net or refer to textbooks, handbooks, standards, and lecture notes to get the required information for the above calculations.
2. Write down the required equation for each calculation used in Excel and include them in an appendix of your report.
3. Write a short description of how any of the equations can be used and what it is used for.
4. Develop an EXCEL sheet that computes all the required parameters listed above (1 - 16)