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

Table of Contents

Objective…………………………………………………………………………………………………………3

Abstract…………………………………………………………………………….4

Theory ……………………………………………………………………………….5

Introduction of experiment …………………………………………………………..6

Procedure ……………………………………………………………………………..7$8

Calculation ……………………………………………………………………………9

Discussion………………………………………………………………………….....10$11

Reference ……………………………………………………………………………..12

Objective

The object of this experiment is to clean the core by toluene or

ethanol to remove contaminants from the Hydrocarbon of the core .

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))

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)

Introduction of experiment Apparatus

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.

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.

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.

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.

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-