ABSTRACT

Porosity

is one of the two most essential reservoir rock properties, of which the other

is permeability. Porosity is an indicator of the storage capacity of a

reservoir. It may be characterized as the proportion of pore volume to bulk

volume of a reservoir. Porosity can be accounted for as either a fraction or as

a percentage.

The

porosimeter was outlined specially to gauge the effective porosity of a core sample.

The effective porosity is the proportion of the interconnected pore spaces to

the bulk volume of the reservoir rock. It is vital to precisely quantify the effective

porosity of a reservoir rock when evaluating the reserves.

In

this experiment, the core porosimeter was utilized to appraise the effective

porosity of a core sample with a diameter of 3.7cm and length of roughly 6cm.

The effective porosity was later assessed to be 22.2%.

CHAPTER 1: INTRODUCTION

Porosity

represents the void within a solid media. Almost all hydrocarbon reservoirs are

made up of sedimentary rocks in which porosity values 10 to 40% in sandstones

and 5 to 25%in carbonates (Peter & Kersey).

There

are frequently disparities between porosity values derived from laboratory analysis

and porosity values decided from well logs. A considerable lot of these

disparities can however be clarified by taking note of contrasts in the meaning

of porosity (Peter & Kersey).

Porosity

can be categorized as total or effective porosity. Total porosity is the proportion

of all the pore spaces in the rock to the bulk volume of the rock, while

effective porosity is the proportion of interconnected void spaces to the bulk

volume (Torsaeter & Abtahi, 2000). Accordingly, only the

effective porosity contains fluids which can be delivered (Torsaeter & Abtahi, 2000).

Figure

1: Sketch of Cross Section of Reservoir Rock

CHAPTER 2: EXPERIMENTAL

APPARATUS & MATERIALS

2.0 INTRODUCTION

With

the end goal of this experiment being to estimate the porosity of a core plug, the

equipment used incorporates the core porosimeter and the Vernier caliper, while

the material utilized was a core plug.

2.1 CORE POROSIMETER

This

is an instrument used for measuring the porosity of a core sample (Schlumberger Oilfield Glossary, n.d.).

Figure

2: Core porosimeter

2.2 VERNIER CALIPER

This

is a measuring instrument used to read directly the dimension of an object, for

this situation, a core plug (American Heritage Dictionaries, 2011).

Figure

3: Vernier Caliper

2.3 CORE PLUG

Core

plugs are samples taken from conventional core for analysis/ investigation. (Schlumberger oilfield glossary, n.d.).

Figure

4: Core plugs

CHAPTER 3: EXPERIMENTAL PROCEDURE

The

procedure for this experiment (Porosity determination using core porosimeter)

was as follows:

1. Before

commencement of experiment, I placed all the valves in a vertical condition and

ensured the regulator in the front panel was rotated fully clockwise.

2. I

turned the unit on and allowed it to warm up for 5-10 minutes.

3. I

then measured and recorded the diameter and length of the core using a vernier

caliper.

4. I

unscrewed the sample holder and inserted the core specimen. I then screwed the

sample holder back into place.

5. Next,

I turned the P2 test valve to the off position.

6. I

then rotated the regulator clockwise until the pressure read 180psi.

7. I

then turned the P1 lock in valve to the off position and allowed P1 to

stabilize before recording the value.

CHAPTER 4: RESULT DISCUSSION

4.1 CONSTANTS OF THE

POROSIMETER

V1 = 60.18cm³

V2 = 165.31cm³

4.2 RECORDED PARAMETERS

Initial Pressure Value, P1

= 180.65psi

Final Pressure Value and

Expansion, P2 = 96.5psi

Diameter, D = 3.7cm

Length, L = 6.3cm

4.3 CALCULATED PARAMETERS

4.3.1 CORE BULK VOLUME, VB

VB

=

………………………………………………………………………………….. (4.1)

Where:

VB

= Bulk Volume

D

= Diameter

L

= Length

VB =

= 67.7cm³

4.3.2 V3

V3

=

………………………………………………………………………………… (4.2)

Where:

P1 = Initial Pressure

Value

P2 = Final Pressure Value

and Expansion

V1 = Constant of

Porosimeter

V3 =

=

112.7cm³

4.3.3 CORE GRAIN

VOLUME, VG

VG = V2 – V3 ………………………………………………………………………………..

(4.3)

Where:

VG

= Core Grain Volume

V2

= Constant of the Porosimeter

VG = 165.31 – 112.7 = 52.7cm³

4.3.4 CORE PORE VOLUME, VP

VP = VB – VG

…………………………………………………………………………………. (4.4)

Where:

VB

= Bulk Volume

VG = Core

Grain Volume

VP = 67.7 – 52.7 = 15cm³

4.3.5 POROSITY,

=

* 100 …………………………………………………………………………………

(4.5)

Where:

VB

= Bulk Volume

VP

= Core Pore Volume

=

* 100

=

22.2%

CHAPTER 5: CONCLUSION

In conclusion, the porosimeter

quickly and precisely measures the effective porosity of a core sample, which

was estimated to be 22.2% for a core plug of length roughly 6cm and diameter of

3.7cm. This information obtained is quite useful to estimate the reserves of a

reservoir.