TABLE OF CONTENTS :

NOTOPICSPAGES

1Abstract / Summary1

2Introduction2

3Aims / Objectives2

4Theory3

5Apparatus5

6Procedures5

7Results6

8Calculation9

8Discussion10

9Conclusions11

10Recommendations11

11References12

12Appendix12

ABSTRACT

The objective of the experiment is to determine the absolute permeability of membrane samples with different thickness using a liquid permeameter and to study the effect of pressure towards the membrane samples. In this experiment, membrane samples with thickness of 0.1, 0.2, and 0.5mm is tested with different pressure of 5, 10, 15, 20 and 30 psi. The results obtained from this experiment are 0.04061 Darcy for 0.1mm sample, 0.032288 Darcy for 0.2mm sample, and 1.6395 Darcy for 0.5mm sample. For sample of 0.5mm, it has the highest permeability compared to 0.1 and 0.2mm sample when tested with 5 psi. For 30 psi, sample 0.5mm still has the highest permeability compared to 0.1 and 0.2mm sample. From this, it can be conclude that sample 0.5mm has the highest permeability.

INTRODUCTION

For a rock to act as a reservoir, it must have two essential properties: porosity and permeability. Porosity is the ability of a rock to hold hydrocarbon (act as storage) whereas permeability is the ability of fluids to pass through a porous material. Porosity alone is not enough for a rock to be good reservoir. Thus it must have permeability, where the pores are connected to each other so that the hydrocarbon can flow through the reservoir rock to the trap where the hydrocarbons will accumulate. The original work on permeability was carried out by Henry Darcy in 1856, thus creating Darcys equation. Darcys equation defining permeability is linked to laminar flow in porous media, and it is not valid for turbulent flow. The unit for permeability is the Darcy. This is defined as the permeability that allows a fluid of 1 centipoise (cP) viscosity to flow at a velocity of 1 cm/s for a pressure drop of 1 atm/cm. Because of most reservoirs have permeabilities much less than a Darcy, milidarcy (md) is commonly used. Average permeability in reservoirs is commonly in the range of 5 to 500 md. Permeability is generally referred to by the letter K.OBJECTIVES

In this experiment, the objectives are:

1. To determine the absolute permeability of mediums (membrane samples) with different thickness using a liquid permeameter. 2. To study the effect of different pressure towards the mediums (membrane samples).

THEORY

In applying Darcys Law, there must be no chemical reaction between the fluid and the rock in order for the law to be valid. The pores also must be completely fills with only one fluid phase. Darcy has performed a series of experiments on the relationship affecting the downward flow of water through sands. Writing the flow velocity as the ratio of volumetric rate to cross sectional area perpendicular to flow q/A in distance L, Darcys Law can be expressed as below:

Where:

q (cm3/s) = total discharge

A (cm2) = cross-sectional area

(cm/s) = flow velocity

(Darcy) = permeability

(cp) = viscosity

(atm) = pressure drop along the sample

(cm) = length

The dimensions of permeability can be developed by substituting the units of the other in the equation. The unit Darcy results from the selection of cgs system units. The permeability in SI systems has dimension of m2.

In defining permeability, Darcys Equation is linked with laminar flow. However, laminar flow is not always achieved especially in gas flows. If the flow rate is high, Darcys Equation is not valid. The range of flow rates in which laminar flow exist depends on the Reynolds number. Reynolds number for porous media is written as follows:

For example, in sand, transition from laminar to turbulent flow occurs in the range of Reynolds number from 1 to 10.

APPARATUS

1. Liquid permeameter (PMI)

2. Sample membranes (0.1, 0.2, 0.5 cm)

3. Distilled water

4. Adapter plate

5. Pressure tank

6. PC (data acquisition and gathering)

7. Ceramic chamberPROCEDURE

1. The samples are prepared to be tested and the o-ring inside the chamber must be covered thoroughly by the sample ( all the samples must be large to cover the o-ring)

2. The samples (membrane) that are used in this experiment, each has different thickness which is 0.1 cm, 0.2 cm, and 0.3 cm.3. The chamber was closed by using the adapter after the sample is inside.4. The pressure valve at the nitrogen gas tank was turned slowly in clockwise direction so that the nitrogen gas can flowed in the chamber.5. Different pressure was used in each test which is 5psi, 10 psi, 15 psi, 20 psi and 30 psi.

6. The test result was being observed and analyzed by using CapWin software.

7. Before the sample was changed, the pressure valve was turned slowly in anticlockwise direction so that no pressure are being applied.8. Step 1 until 5 was repeated by using different type of samplesRESULTS

Diameter: 3 cm

Fluid viscosity (cp): 1.0

Differential pressure

(psi)Average permeability (Darcy)

Sample 1

(0.1 cm)Sample 2

(0.2 cm)Sample 3

(0.3 cm)

50.171680.0282845.1898

100.0182310.0253231.7664

150.00515900.0447010.59919

200.00455930.0376740.38939

300.00342070.0254580.25225

Differential pressure, P (psi)Differential pressure, P (atm)Flow rate, q

(cc/s) q/A

(cm/s)P/L

(atm/cm)

0.653780.044490.0185100.0026190.1483

0.659210.044860.351790.049770.1495

0.831860.056602.55540.36150.1887

1.27650.086865.90690.83570.2895

1.73700.118211.3411.60460.3940

2.15140.146412.8131.81280.4880

2.58230.175714.6752.07630.5857

3.06220.208415.8912.24830.6947

3.51150.238912.5201.77140.7963

Table 1: Membrane samples no 3 at 5psi.

Graph 1: Membrane sample no 3 at 5psi.SAMPLE OF CALCULATION

For sample no 3 at differential pressure 5psi,

Sample no

: 1

Length / thickness (cm) : 0.300

Diameter (cm)

: 3.000

Fluid viscosity, (cP)

: 1.000

Area, A (cm2)

: 7.068

Unit conversion

(a) 1 psi

0.068 atm

3.5115 psi 0.2389 atm

*The rest of differential pressures (psi) are converted into (atm) as shown in (a)

(b) q/A

cm/s

*The rest of the distilled water velocities are calculated by using the same method of calculation shown in (b).

(c) P/L

0.7963 atm/cm

DISCUSSIONS

The main objective of doing this experiment is to determine the permeability of different samples of membranes. We use water as the fluid with known viscosity. Darcys equation is used by taking the average Darcy permeability constant. Each sample is tested for 5 times at different values of pressure gradient which are 5, 10, 15, 20 and 30 psi. From the results, it shows that the permeability for sample PP1 with thickness 0.1mm get from this experiment is 0.04061 Darcy. The permeability for sample PP2 with thickness 0.2mm is 0.032288 Darcy. The permeability for sample PP5 with thickness 0.5mm get from this experiment is 1.6395 Darcy. Permeability of a rock is a measure of the ability of a porous material connected to allow fluids to pass through it. The exits of permeability of the rock cause fluid to pass through into it. The hydrocarbon which is oil and gas will flow through the rock with high porosity and permeability. Therefore, the hydrocarbon can be stored in the rock for the concentration and accumulation of oil and gas.From the above results, it can be seen that for sample PP1, PP2 and PP5 the average permeability is decreasing. In conclusion, all the average Darcy permeability constants are declining. It can be concluded that as the pressure increases, the permeability will decrease. As for PP 5 has the highest permeability compared to PP1 and PP2 based on 5 psi. As for 30 psi, PP5 still has the highest permeability compared to PP1 and PP2. This can be concluded that PP5 has the highest permeability compared to others.

CONCLUSION

As a conclusion, different type of membranes will give different permeability. Pressure may also affect the rate of permeability. The permeability is presented as the results of the permeability are obtained by using the Darcys equation. As the results can be obtained from the Darcys equation, it shows that laminar flow was occurred. From the result, we can conclude that the permeability of the sample PP5 with thickness 0.5mm is higher compared to sample PP1 and PP2. It shows that sample PP5 has larger capacity of fluid can pass through it. In a conclusion, the larger the thickness of the membrane, the greater capacity of fluid can pass through it. Good reservoir has higher porosity and permeability so that it has the least problem for fluid to flow. Therefore the objective which is to determine the permeability by relating to Darcys equation is achieved.

RECOMMENDATION1. The pressure of the liquid permeability should be set at the correct value in order to get accurate data.

2. The chamber plate and adapter plate should be open or close carefully by using the tools provided to prevent any disturbance to the sample to be tested.

3. The water in the chamber should be continually refilled before it is reduced because it indicates the machine operated appropriately.

4. The sample should be placed at the centre of the adapter plate so that there is full-flow of fluid through the area of the sample.

5. The pressure valve should be closed during the changing of the sample for safety precaution.

1) REFERENCES

2) Richard C.S (1998). Elements of Petroleum Geology 2nd Edition. California, USA. Academic Press.

3) Norman J.H (2001). Nontechnical Guide to Petroleum Geology, Exploration, Drilling and Production 2nd Edition. Oklahoma, USA. PennWell Corporation.

4) http://www.glossary.oilfield.slb.com/en/Terms/p/permeability.aspx (31/10/2013, 11.00 pm)5) http://en.wikipedia.org/wiki/Permeability_(earth_sciences) (31/10/2013, 11.00pm)6) Basic Petroleum Engineering Laboratory Manual APPENDICES