ABSTRACT meaning of porosity (Peter & Kersey). Porosity can

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.

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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.