This experiment aimed to determine the filtration rate of mud under 90-100 psi pressure using a standard API filter press. Mud was prepared using water and bentonite and tested in the filter press, which applied pressure for 30 minutes. The mud formed a 4 mm thick cake and 18.7 cc of filtrate was collected. Temperature affects viscosity and filtration rate, so should be reported. The experiment showed how mud cake thickness and filtrate volume can be measured under controlled pressure and temperature using a filter press.

1. Soran University
Faculty of Engineering
Department of Petroleum Engineering
Drilling Engineering I [ PETE 308]
Title: Filtration
Experiment No.: 7
Name: Muhammad Sulaimon Rasul
Group: B2
Date: 28 OCT 2019
Supervisors: Mr. Jagar Ali, Mr. Fouad Yossifi, Mr. Rawezh Najat

2. Contents
Aim………………………………………………………………………………………….…….1
Theory…………………………………………………………………………………….…….…1
Apparatus…………………………………………………………...…………………………..…2
Test Equipment…………………….……..………………………...…………………………..…3
Procedure………………………………………………………………………………………….4
Calculation………………………………………………………………………………...………5
Result and Discussion……………………………………………………………………………..6
Conclusion………………………………………………………………………………………...6
References…………………………………………………………………………………………7
List of Figures
Figure 1 Electronic mud mixer………….…………………………………...….….……….….…2
Figure 2 Beaker. …………………………………………….………..........…………….….…….2
Figure 3 Lab Spatula ……………….…….….…………………….…………………………..….2
Figure 4 Standard API Filter Press …...…………………………….…………………………….2
Figure 5 Bentonite …...…………………………….……………………………….…………….2
Figure 6 Filter Paper …...……………………………………..…….…………………………….2
List of Tables
Table 1 Experimental and Theorical Results……………………………………………………..6

3. Aim
Determining the filtration rate of mud under 90-100psi and the thickness of mud cake which form
under the condition using a device named Standard API Filter Press.
Theory
Mud filtration create due to the differential pressure between Hydrostatic pressure that developed
due to the mud column fluid and formation pressure. However, the hydrostatic pressure exceeded
over the formation pressure causing an injection of mud filtrate into a porous and permeable
formation leaving behind deposited mud cake on the wall of the borehole (Churchill et al., 1977).
Fluid loss usually occurs when the formation permeability allows the filtrated mud to pass thought
a porous path. The lost of fluid into the formation used to be a Mud Filtrate and the solid particles
that form on wall of the borehole side used to be a Mud Cake. The rate of fluid lost is controlled
by the solid particles of mud cake which formed on the wellbore wall. Since, two type of filtration
can occur. First while circulating which recognized as dynamic filtration and the Static filtration
while the mud at rest. The static filtration will make mad cake thicker with time, since the rate of
fluid loss decreases with growing the mud thickness (Steffe, 1996).
The test is used to monitor the rate of mud filtrate and how much mud can be thick while being
forced by a filter press device at specified time range, temperature and pressure. The mud cake
used to be filtrated via a filter paper then measuring the residual deposits upon it (Swamee et al.,
2011).
Filtration mostly affected by the pressure while compressing the filter cake, causing reduction in
permeability that affects reducing filtration rate. At the down wellbore an increase in temperature
can have effect on filtration rate by reducing the viscosity of a fluid which makes fluid injection
into the formation easer (Churchill et al., 1977).
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4. Apparatus and Materials
Apparatus
• Electronic mud mixer: Is a device used to mix liquid with solid particles. Shown in
Figure 1.
• Lab Spatula: Used to mix mud and water manually. Shown in Figure 3.
• Beaker: is a cylindrical container used to measure volume of a liquid. Shown in Figure 2.
• Standard API filter Press: Is a device used to measure mud thickness and mud Filtrate.
Shown in Figure 4.
• Filter Paper: Is a paper used to filtrate the fluid and hold the solid particles. Shown in
Figure 6.
Materials
• Water.
• Bentonite: Is a weighting material used to create a WBM. Shown in Figure 5.
• Mud.
Figure 1 Electronic mud
mixer
Figure 2 Beaker
Figure 3 Lab Spatula Figure 4 Standard API Filter Press
2
Figure 5 Bentonite
Figure 6 Filter Paper

5. Test Equipment
1. The low-pressure test is made using standard cell under the API condition of 100psi for 30
min at room temperature.
2. Another special cell will be used to measure filtration rate at elevated temperature. The
filter press used for filtration tests consists of four independent filter cells mounted on a
common frame.
3. Each cell has its own valve such that any or all cells could be operational at the same time,
and toggle valve on the top of each cell could be operated independently for the supply of
air for each individual cell.
4. Special high pressure and high temperature filtration test are run in the laboratory
simulating formation temperature and formation back pressure.
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6. Procedure
1. Loosen the T-screw until the filter cell can be removed from the frame. Then remove the
filter cell and disassemble it.
2. Be certain that all parts of the filter cell are dry and clean. And check to see that the rubber
gasket in the base cap is evenly placed.
3. Check the filtrate tube in the base cap to be certain it is free of obstruction. After that place
the screen in the base cap with the wide rim up.
4. Place filter paper on the top of the screen, also place the second rubber gasket on top of the
filter paper. Then replace the cell body.
5. Turn the cell body clockwise until it securely fastens into the J slots and check to see that
the rubber gasket is evenly fitted into the top cap. Then fill the filter cell to within the
drilling mud sample.
6. Check to see that the hole in the top cap is free of obstruction. Now place the top cap on
the filter cell and place the cell body into the frame.
7. Tighten the T-screw securely.
8. Place a graduated cylinder under the filtrate tube and adjust the support to keep the cylinder
under the filtrate tube.
9. Close the pressure-relief valve and until the pressure is 100 (± 5) psi. Start timing
immediately. And allow the test to continue for 30 minutes.
10. Read and make note of the amount of filtrate in the graduated cylinder to the nearest 0.1
cc, then open the valve on the regulator by turning counterclockwise.
11. Wait until all pressure is released. Then remove the cell from the frame by loosening the
T-screw.
12. Remove the top cap and pour the mud out. Remove the bottom cap from the cell. And turn
the bottom cap upside down on a solid surface and remove the filter paper.
13. Measure the thickness of the filter cake to the nearest 1/32 in.
14. Wash and dry all parts of the filter press.
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7. Calculation
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8. Result and Discussion
Table 1 Experimental and Theorical Results
Regarding to the Table 1, a drilling mud was prepared with the volume of 200 cc using a mixture
of water and bentonite as mentioned their properties in the table as the Density Test report. A
Standard API Filter Press used to press the mud and filtrated via a filter paper to a graduated
cylinder and the volume of filtrate has been measured after 30min of compressing. The mud
thickness in the table has measured via a rule injected to the mud and has 4 mm thick. Should note
that at which temperature the experiment has done because the viscosity changes with temperature
and also the rate of filtration change. Addition to range of pressure should not exceed 100psi for
accurate data. Also, in borehole condition temperature and pressure vary in each point according
to their depth.
Conclusion
This experiment can conclude that, a drilling mud could form a mud cake and mud filtrate in
different pressure and temperature condition that can measure their rate of filtration and mud
thickness with a device named Standard API Filter Press.
Material Mass (gm) Volume (cc) Density (ppg)
Thickness
(mm)
Water - 195.67 8.33 -
Bentonite 10.825 4.33 20.8 -
WBM - 200 8.6 -
Mud Filtrate - 18.7 - -
Mud Thickness - - - 4
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9. References
Churchill, S.W. (1977). "Filtration factor equation spans all fluid-flow regimes". Chemical
Engineering: 91–92.
Steffe, J.F. (1996). Rheological Methods in filtration Process Engineering (2nd ed.). ISBN 0-
9632036-1-4.
Swamee, P.K. and Aggarwal, N. (2011). "Explicit equations for laminar flow of Bingham plastic
fluids". Journal of Petroleum Science and Engineering. doi:10.1016/j.petrol.
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