The document details a laboratory experiment conducted in the Petroleum Department of Koya University, focused on cleaning core samples using various solvents to improve measurements of porosity and permeability. It outlines the procedures, including the use of a Soxhlet extractor and specific solvent mixtures to remove contaminants from hydrocarbon samples. Additionally, it discusses the importance of the number of extraction cycles and the drying process for accurate measurements.

1. Koya University
Faculty of engineering
Petroleum department
Reservoir engineering laboratory
(Core cleaning)
Dec.10th
.2015
Lab EXP.(2)
Supervised By Prepared By
Mr. Haval Bakhtiar star m.
Mr. Barham
Submitted on: Dec. 17th
2015

2. Table of Contents
Objective…………………………………………………………………………………………………………3
Abstract…………………………………………………………………………….4
Theory ……………………………………………………………………………….5
Introduction of experiment …………………………………………………………..6
Procedure ……………………………………………………………………………..7$8
Calculation ……………………………………………………………………………9
Discussion………………………………………………………………………….....10$11
Reference ……………………………………………………………………………..12

3. Objective
The object of this experiment is to clean the core by toluene or
ethanol to remove contaminants from the Hydrocarbon of the core .

4. Abstract
when sample pull out from the well it contain many
impurities and solid particles that effect on porosity and
permeability measurement .also the sample undergo
many conversion due to difference in temperature and
pressure though bottom hole till surface .so the samples
must be placed in the bottom hole temperature and
pressure then the sample must be cleaned before
measuring porosity and fluid saturation
The best solvent for rock types was a 50/50 mixture of
toluene/methanol, or the equivalent, containing I %
ammonium hydroxide. Toluene, the most commonly
used solvent for core cleaning, was one of the poorest
solvents tested. The solvents that are effective in
removing poorest solvents tested. The solvents that are
effective in removing surfactants can be used to clean
contaminated core. (Soxhlet, F. (1879))

5. Theory
A Soxhlet extractor is a piece of laboratory apparatus
invented in 1879 by Franz von Soxhlet. It was originally
designed for the extraction of a lipid from a solid material.
Typically, a Soxhlet extraction is used when the desired
compound has a limited solubility in a solvent, and the
impurity is insoluble in that solvent. .( Soxhlet, F. (1879))
It allows for unmonitored and unmanaged operation while
efficiently recycling a small amount of solvent to dissolve a
larger amount of material. Predictions of reservoir
performance are usually based on laboratory measurements of
core properties. The measurement of permeability and
porosity using core cleaning. The solvents used to remove oil
must not react with the rock; they include toluene and xylene.
Jensen, William B. (December 2007). Typically, water is
removed by heating the rock, many special core analyses,
including capillary pressure, relative permeability, and
saturation exponent, are affected by the wettability of the
core. (Harwood, Laurence M.; Moody, Christopher J. (13 Jun 1989)

6. Introduction of experiment
Apparatus

7. Procedure
1- Remove the sample from the oil and carefully blot dry an excess oil.
2- Place the sample inside the Wathman thimble and quickly weight the
sample and sample using the analytical balance.
3- Leave the sample in the thimble.
4- Re- assembles the apparatus as shown in the figure 1, tighten the
ground joint fitting but don’t apply sealing or lubricant.
5- Turn on the water supply to begin circulation in the condenser.
6- Turn on the heater and adjust the rate of the boiling so that the reflex
from the condenser is a few drops of solvents (toluene) per second.
7- Allow the extraction to continue for several hours with a minimum of 7
cycles or until the thimble content dissolved oil stain and is close to original
color.
8- Monitor the toluene level during the extraction to ensure that the
sample remains completely submerged in addition.
9- When the extraction is complete the solvent will be clean or water white
depending on the color of oil removed.
10- Read the volume of the water collected in the water trap, if any.
Note
In many cases the sample have been prepared using oil only to saturate
the core sample, therefore the absence of water does not mean an invalid
test.
11- Return the thimble containing the sample to the instructor, who will
place them in the drying oven at (105 - 120) degree centigrade.
12- The instructor will advise when to return to collect the dried sample
(sometimes will be the next day).
13- Place the dried sample in desiccators for a few hours prior to weighting
to ensure that they are completely dried.

8. 14- Place the thimble containing the sample in the analytical balance,
measure the weight of the thimble and dried core sample and record the
result.
15- Remove the sample and then weight the empty thimble, record the
results or note if there are any grains of the sample remaining in the
thimble in the space provide.

9. DISCUSION
Core cleaning is the one of all-important test performed for core
sample cleaning methods must be developed to remove these
surfactants, allowing restoration of plugs to their natural wettability.
We have main reasons for doing this experiment the first one for
cleaning a sample because when we obtain a sample in a reservoir
very dirty and not proper for getting a property like porosity &
permeability…. later we can get any property of a sample accurately
Some point in this experiment we noticed, we can discuss like that:
1-Number of cycles is important to clean the sample completely
.heater arrangement is critical since if determine time of each cycle
and rate of solvent condensation that must be few drops in each
second to clean the sample efficiently.
2- We used a carbon sylysium and put it in the bottom of the flask
in order to that makes a uniform temperature (bubble) during
making a bubble.

10. 3- When a sample entirely cleaned must be put it in oven until the
sample completely dried to more accurately & remove saturation
water in a sample then weigh the sample.
Q-What’s the main solvent that used to cleaning?
A-It has been shown that mixtures of solvents work better than single
solvents, Common solvent mixtures are chloroform/methanol,
toluene/methanol, toluene/ethanol, benzene, and carbon disulphide among
others. Some mixtures work better for different types of rocks and fluids.

11. References
1. Harwood, Laurence M.; Moody, Christopher J. (13 Jun 1989).
Experimental organic chemistry: Principles and Practice
(Illustrated ed.). Wiley-Blackwell. pp. 122–125. ISBN 0-632-
02017-2.
2. Soxhlet, F. (1879). "Die gewichtsanalytische Bestimmung des
Milchfettes". Dingler's Polytechnisches Journal (in German) 232:
pp. 461–465.
3. Jensen, William B. (December 2007). "The Origin of the Soxhlet
Extractor". Journal of Chemical Education (ACS) 84 (12): pp.
1913–1914. doi:10.1021/ed084p1913.
4. Cumpson, Peter; Sano, Naoko (February 2013). "Stability of
reference masses V: UV/ozone treatment of gold and platinum
surfaces". Metrologia (IOP) 50 (1): pp. 27–36. doi:10.1088/0026-