This document describes an experiment conducted using a helium porosimeter to determine rock porosity. The experiment was supervised by Mr. Haval Hawez and Mr. Barham Sabir, and conducted by Muhammad Faisal on May 5, 2016. The helium porosimeter uses helium gas expansion and Boyle's law to calculate a rock sample's grain and pore volume, from which porosity and grain density can be determined. The procedure involves connecting the helium porosimeter to a gas source, calibrating it, loading a rock sample, and using software to collect and analyze pressure and volume measurements to calculate porosity.

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Petroleum department
3rd stage
Group (A4)
Reservoir Lab
4th
Experiment:
Helium Porosimeter
Date of experiment: May 5th
2016
Supervised by:
Mr. Haval Hawez &
Mr. Barham Sabir
Prepared by:
Muhammad Faisal

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Aim of experiment:
This test can be used and conduct on a new generation of Helium
Porosimeter Production educational series, and new generation of
Helium with hand-operated valves. HeP is a Helium Porosimeter
for Grain volume determination on samples (standard, irregular or
coated) based on Boyle-Marriott’s law.

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Theory:
The Helium gas expansion porosimeter enables the
determination of a sample’s (1” or 1.5” diameter) grain and pore
volume via an isothermal helium expansion and the application of
Boyle’s law and Charles’ law. Subsequently, porosity and grain
density can be calculated. A provided excel template facilitates the
computation of these parameters as well as calibration.
The grain density and porosity is measured on cleaned and
dried plugs by a helium porosimeter. The Helium-porosimeter
measures the grain volume Vg of the sample. The empty sample
container of the porosimeter has a volume VS before the sample is
inserted. A reference volume Vr is filled by helium and the pressure
Pr is recorded. The gas is expanded from the reference volume to
the sample container and the resulting pressure PX is recorded.
The grain volume is determined by applying Boyles low: PIVI = P2V2
or Pr*Vr = P*(Vr+Vs-Vg).
Helium porosimetry. For helium porosimetry, effective
porosity is determined by first placing the specimen into a steel
chamber (known volume) of the Boyle's law double-celled helium
porosimeter (Loman et at 1993). Helium is then allowed to
isothermally expand into the chamber from a reservoir of known
volume and pressure until equilibrium pressure is reached (20-60
min). The grain volume can be calculated from measurement of the

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new gas pressure. The bulk volume of the specimen is determined
by immersion of the specimen in mercury. Or Mathematically.
Effective porosity is calculated by taking the difference
between the grain volume and bulk volume:
∅ℎ𝑒 = (𝑉𝑏 − 𝑉𝑔)/𝑉𝑏
Where ∅ℎ𝑒 is the effective porosity determined by helium
porosimetry, Vb is is the bulk volume of the specimen determined
by mercury immersion and Vs is the grain volume. Further details
on the method and procedures can be found in the literature (e.g.
American Petroleum Institute 1960; Luffel & Howard 1988). As
described here, this method is based on the Boyle—Mariotte law.
That is a change in gas volume or gas pressure causes a
commensurate change in gas pressure or volume, assuming that
temperature remains constant.

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Introduction to instruments and devices:
HePLEX® Helium Porosimeter & computer

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Helium Gas bottle (source)
Procedures:
1- Connect process fitting at front side of the cabinet to a suitable dry gas facility, rating up
to 220 psi.
2- Remove the cap at the bottom of the transmitter. Plug cable from the transmitter to the
USB at right side of computer.
3-
4- Reset pressure display (offset) You can reset pressure sensor LEX locally as follow:
• Press SELECT (left button) 3 times to display MANO at the bottom of the screen
• Press ENTER (right button)
• ZERO is displayed at the bottom of screen
• Press ENTER to offset the device.
Alternatively, you can remotely offset pressure reading from AppliLab software by Click
on Offset button labeled”0” on the interface. Operator is guide to operate valves in
sequence.

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5- Set reference pressure:
According to option, the reference pressure is 100 psig or 200 psig. Adjust the pressure
supply at the regulator of the gas facility (upstream N2 Porosimeter) to get about 120 or
220 psig (according to option). There is no need to get sharp 100 psig or sharp 200 psig.
A pressure from 95 to 105 or respectively 190 to210 psig is acceptable. A relief valve built-
in HeP will flow out exceeding pressure.
• Open valve V01
• Read the pressure on the cabinet
• If the pressure reading is less than set point, turn clockwise the cabinet regulator knob
to obtain the expected value and close back valve V01
• If pressure reading is greater than set point:
• Close valve V01
• Open valve V02 while matrix is open to atmosphere to decrease pressure
• Turn anti clockwise the knob
• Close back V02
• Open valve V01, turn clockwise the regulator knob to obtain the expected value and
close back valve V01
6- Select matrix in line:

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7- Billets (calibrated discs):
Billets are used during calibration and may be used to reduce free room when small
sample is loaded into matrix.
8- Report and Template:
Template and reports files are EXCEL files with three tabs: REPORT, CALIB and PRINT.
Operator is not allowed to edit manually template. Template is updated at tab CALIB by
AppliLab software during calibration.
9- Run number:
10- Trend facility:
11- Actions:

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12- Measure operation:
Remember that steady temperature is primordial to correct calibration and measure. If
you touch the reference tank under pressure, you willnotice a drift in the pressure reading.
 Loading sample into matrix:
For sample of 1 or 1.5” nominal diameter we use the same matrix and a liner. Open matrix by
unscrewing (anti clockwise) the top handle for about one revolution. Then remove the metal
cylinder from the frame. For sample of nominal diameter 1”, drive gently sample into the liner.
For sample of nominal diameter 1.5”, remove the liner then load sample into the matrix. Make
sure that there are no sand particles on the top of the metal cylinder (or wipe them with the
finger). Drive back the metal cylinder into its frame. Tight the matrix by rotating the top
handles clockwise.
 Input sample information:
Such as sample name, field, well, sample description, sample weight, diameter and length and
test operators name as well.
13- Click on START and follow the instructions of AppliLab program.
14- Shutoff procedure:
1. Click STOP or No at prompt YES: process measure. No: stop.
2. Bleed off the pressure of gas at the gas supply.
3. Switch off all the valves.

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4. Quit AppliLab application.
5. Pressure display on cabinet is auto switched off.
6. Shut down Windows operating system and switch off the computer.
7. set back the billets (calibration discs) in their case.

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Discussion:
Q1) why do we have to reset the pressure display?
A1) resetting is required to prevent any erroneous results.
Q2) what happens if the pressure of the helium gas that goes from the gas
facility to the porosimeter is too large?
A2) a relief valve built-in HeP will flow out exceeding pressure.
Q3) what are the billets used for?
A3) Billets are used during calibration and may be used to reduce free room
when small sample is loaded into matrix.
Q4) why if you touch the reference tank under pressure, you will notice a
drift in the pressure reading?
A4) because any alternation in the temperature of the tank causes change
in the pressure of the gas.
Q5) when the gas is expanding inside the matrix cup the system waits till
stability is reached, what happens if this step is skipped?
A5) this action results in erroneous consequences and results such as
negative porosity.
Q6) what are the advantages and limitations of porosity acquisition by this
method?
A6) the results of the conducted experiments prove that the helium
porosimeter provide the repeatability of measurements, high precision and
small random error of the obtained results in the repeatability conditions.
The basic problems may arise in reference to the methods and calibration

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procedures, deciding about the correctness of the results and level of
systematic errors (laboratory loading).
References:
Ahmed, U. & Mehan, N., 2016. Unconventional Oil and Gas
Resources: Exploitation and Development. NewYork: CRC
Press.
Aplin, A. C., 1999. Muds and Mudstones: Physical and Fluid-
flow Properties. 158ed. London: Geological Societyof
London.

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