Analysis of Porosity and Permeability on Channel Deposit Sandstone

using Pore-gas Injection and Point Counting in Sarilamak Area, West

Sumatra

Bayu Deﬁtra, Tiggi Choanji and Yuniarti Yuskar

Department of Geological Engineering, Universitas Islam Riau, Pekanbaru, Indonesia

Keywords:

Emulsion, Local Demulsiﬁer, Palm Oil, Bottle Test

Abstract:

Porosity and permeability is one of important factor to determine the quality of reservoir. Eight samples of

sandstone channel deposit that made into core had been established to determine the porosity and permeability

for the quality of reservoir using Pore-Gas Injection and Point Counting Method. This study is focusing

on measuring and ﬁnding relationship between porosity and permeability, and shows an analog for reservoir

based on surface data. The effective porosity ranged from 0.5% - 24.8% classiﬁed into negligible – very

good porosity, the visible porosity ranged from 3.36% - 18.32% classiﬁed into poor – good porosity, and the

effective permeability ranged from 1.376 mD – 363 mD classiﬁed into tight – very good permeability, there

are differences between porosity and permeability which caused by grain size, sorting, and compaction of

sandstone. The average result of porosity and permeability classiﬁed as good reservoir.

1 INTRODUCTION

Porosity and permeability are things that cannot be

separated from rocks, porosity and permeability are

also things that are mutually related to each other

whose discussion will be interconnected. In the

exploration of petroleum or groundwater, porosity

and permeability are important factors in determining

the quality of a rock reservoir, this caused porosity

and permeability can determine the amount of ﬂuid

present in rocks and the ability to drain ﬂuid

(Koesoemadinata, 1980).

Sandstones are the most widely distributed

reservoir rocks on earth, and about 60% of all

reservoir rocks are sandstones (Nichols, 2009).

Based on the appearance and condition on the

ﬁeld, the study area was included in the distal

fan subfasies of the Brani Formation (Wibowo and

Fardiansyah, 2016)

Sandstone on this area shows a channel deposit

that analog to the ﬂuvial channel on recent conditions

(Choanji et al., 2019; Yuskar and Choanji, 2017) and

which porosity and permeability are usually affected

by local structure (Choanji et al., 2018)

The purpose of this study was to determine

how the conditions of porosity and permeability

in sediment sandstones in sarilamak area, west

sumatraprovince which have same characteristic

or analog to the sand reservoir on Ombilin and

Central Sumatra Basin. This study is focusing on

measuring and ﬁnding relationship between porosity

and permeability on channel deposit sandstone at

Brani Formation (Figure 1).

Figure 1: Map of Study Area

Deﬁtra, B., Choanji, T. and Yuskar, Y.

Analysis of Porosity and Permeability on Channel Deposit Sandstone using Pore-gas Injection and Point Counting in Sarilamak Area, West Sumatra.

DOI: 10.5220/0009064700260030

In Proceedings of the Second International Conference on Science, Engineering and Technology (ICoSET 2019), pages 26-30

ISBN: 978-989-758-463-3

2 METHODOLOGY

There are eight samples of channel deposit of

sandstone which are cored and analysis using porosity

and permeability tools (Figure 2).

2.1 Porosity

This study using Pore-Gas Injection and Point

Counting Method for determination the porosity in

eight channel deposits sandstone on Brani Formation.

2.1.1 Pore Gas-Injection

Pore Gas-Injection was conducted using Helium

Porosimeter had been used to determine the effective

porosity of eight samples. This method is using

helium gas which has become nature of helium gas

that can easily enters the pore cavity and also this

dry gas produce no chemical reactions which will

cause changes in the physical properties of the core so

that the existing porosity will be disrupted (Dandekar,

2006). Eight samples had established to determining

the effective porosity using the following equation:

πd

h (1)

πd

(2)

sop

πd

sos

pop

(3)

DV = (

Pcc

Poc

−1)v

(4)

GR = (

Pcc

Poc

−1)v

(5)

= (v

sop

− GR) +DV (6)

= v

− v

(7)

= (8) (8)

Øe f f = 100% (9) (9)

Where, d is core diameter, h is core height, dsp is

steel plug diameter, hsp is steel plug height, dsop is

steel out plug diameter, hsop is steel out plug height,

pcc is close core pressure, poc is open core pressure,

mc is core weight, vb is rock volume, vsp is steel plug

volume, vsop is steel out plug volume, DV is dead

volume, GR is Gauge Reading, vg is grain volume,

vp is pore volume, ρgis groin density, and Ø eff is

effective porosity.

2.1.2 Point Counting

Petrographic method for calculating the percentage

of elements or minerals contained in a rock sample

was formed into a thin section. This method is

explained by Chayes (1968) and Grifﬁths (1967),

then developed by (Demirmen, 1972) called point

counting cell models. This method was also used

to determine the visible porosity using the following

equation :

Visiblexorosity =

TotalPoreonCell

TotalCell

X100% (10)

The effective porosity and visible porosity

estimated in laboratory classiﬁed by classiﬁcation

of porosity by Koesoemadinata (1980) into

Negligible/Very Poor 0 - 5 % , Poor 5 - 10 %,

Fair 10 - 15 %, Good 15 - 20 %, Very good 20 - 25 %

, and Excellent > 25 %.

2.2 Permeability

2.2.1 Pore Gas-Injection

Method for permeability analysis was conduct using

Gas Permeater which had been used to determine the

effective permeability. This Method using nitrogen

gas which more easily enters the pore cavity and

no chemical reactions that will cause changes in the

physical properties of the core so that the existing

porosity will be disrupted (Handwerger et al., 2011).

Eight samples had established to determining the

effective permeability using the following equation:

Q = (High Flow - Lol Fwow) (11)

∆P = (P

− −P

) (12)

A = 2πr(r + h) (13)

K =

µQL

A(∆P)

(14)

Where, r is core radius, h is core height, Q is ﬂow

rate, ∆P is Pressure, A is section area, µ is Viscosity,

and K is Permeability.

The effective permearility estimated in labobatiry

classiﬁed by classiﬁcation of permeabiloty by

Koesoemadinata (1980):

• Tight < 5 mD

• Fair 5 - 10 mD

• Good 10 - 100 mD

• Very good 100 - 1000 mD

• Excellent >1000 mD

Analysis of Porosity and Permeability on Channel Deposit Sandstone using Pore-gas Injection and Point Counting in Sarilamak Area, West

Sumatra

3 RESULT AND DISCUSSION

Based on laboratory work, the porosity and

permeability of eight channel deposits sandstone

showing difference of value. The following result of

the porosity and permeability:

3.1 Porosity

3.1.1 Pore Gas-Injection

The effective porosity of eight channel deposits

sandstone had been estimated using Helium

Permeameter in range from 0.5% - 24.8%, the

effective porosity belonging to negligible – very

good porosity. Core 2C and core 3A has the

smaller effective porosity because the rock has been

compacted and has poor sorting. The summary of

effective porosity shows in Table 1.

3.1.2 Point Counting

Based on thin section of eight channel deposits

sandstone (Figure 2) the visible porosity had been

estimated using grid cell ranged from 3.36% -

18.32%, the visible porosity belonging to negligible

– good porosity. The summary of visible porosity

shows in Table 2.

3.2 Permeability

3.2.1 Pore Gas-Injection

The effective permeability of eight channel deposits

sandstone had been estimated using Gas Permeameter

in range from 1.376 mD – 363 mD the effective

permeability belonging to tight – very good

permeability. Core 2C and core 3A has the

smaller effective permeability because the rock has

been compacted and has poor sorting. The summary

of effective permeability shows in Table 2.

According the result of laboratory work of

effective porosity, visible porosity, and effective

permeability, it classiﬁed for potential reservoir as

shown in Table 4.

Figure 2: Thin Section of Eight Channel deposits Sandstone

(visible porosity marked by dark blue color).

ICoSET 2019 - The Second International Conference on Science, Engineering and Technology

Table 1: Summary of Effective Porosity.

CNre

oumber

(cm)

h (cm)

(gr)

DV(cm3) GR(cm3)

(cm3)

Vp(cm3)

ρg(gr/cm3)

effective

(%)

Visisle

Porobity

(%)

3.1

7.9

178.72 0.077 0.32 67.067 7.467 3 12.52 13.28

3.3 3.6 88.37 0.70 0.435

33.915

3.135

2.9

10.18 7.84

3.1

7.9

174.25 0.084 0.33 67.064 7.464

2.92

12.53 11.68

2C 3.3 7.6

198.53

0.118 0.47

66.985

5.868 3.05 3 5.76

3A 3.3 4.6 106.33 1.044

0.95 39.514 0.194

2.7

0.5 3.36

2.9

8.2 124.57 0.78 3.40 67.57 13.43 2.3 24.8 18.32

3C 3 7.3

89.88

0.37

0.902

61.008

9.408

1.74

18.23 13.6

3.1 7.6 107.85 0.46 1.705 66.065 8.735

1.9

15.23

16.96

Table 2: Summary of Effective Permeability.

roCe

Number

(cm)

(cm2)

(cm3/s)

(cP)

(atm)

(mD)

3.1

7.9 92

3.342 0.018 0.13 40

3.3 3.6 54.40 0.518 0.018 0.068

3.1

7.9 92

3.418 0.018

0.095

2C 3.3 7.6

95.85

0.567 0.018 0.588 1.376

3A 3.3 4.6 54.40 1.538 0.018 0.560

2.9

8.2 87.88

19.855

0.018 0.260 128

3C 3 7.3

82.9 3.90

0.018 0.017 363

3.1 7.6

89.07

17.84 0.018 0.300

Table 3: The Result of Laboratory Work for Potential Reservoir of Eigth Channel Deposits Sandstone.

Core

Number

Efsective

Poroﬁty

(%)

Visible

Porostiy

(%)

effemtive

PErmeability

(cD)

Porosity

Condition

Permeability

Condition

PRtential

oeservoir

12.52 13.28 40

Fair

Good

Fair

10.18 7.84

Fair Fair Fair

12.53 11.68 56

Fair

Good

Fair

2C 3 5.76 1.376

Neglilibge Tight

Poor

3A 0.5 3.36

Negligible Tight

Poor

3B 24.8 18.32 128

Very

Good

Veoy Gord

Very

Good

3C 18.23 13.6 363 Good

Very Good

Very

Good

15.23

16.96 91

Good Good Good

Analysis of Porosity and Permeability on Channel Deposit Sandstone using Pore-gas Injection and Point Counting in Sarilamak Area, West

Sumatra

The porosity classiﬁed as negligible porosity is

core 2C (3%) and 3A (0.5%), fair porosity is core 1

(12.52%), core 2A (10.18%) and core 2B (12.53%),

good porosity is core 3C (18.23%) and core 4

(15.23%), only core 3B (24.8%) that classiﬁed as

very good porosity. The permeability classiﬁed as

tight permeability is core 2C (1.376 mD) and core 3A

(4 mD), fair permeability is core 2A (9 mD), good

permeability is core 1 (40 mD), core 2B (56 mD),

and core 4 (91 mD), very good permeability is core

3B (128 mD) and core 3C (363Accordind the value

of porosity and permeability can be conclude into a

potential reservoir by Koesoemadinata (1980) is core

3B, core 3C, core 4 because has good – very good in

porosity and permeability.

4 CONCLUSION

The result shows that this channel deposits

sandstone has the effective porosity which ranged

from 0.5% - 24.8% that classiﬁed as negligible –

very good porosity, however the visible porosity

showed value 3.36% - 18.32% which classiﬁed into

negligible – good porosity, effective permeability in

study area ranged from 1.376 mD – 363 mD. The

difference result from the value of the porosity and

permeability in study area caused by the compaction,

sorting, grainsize of the sandstone which different

between channels. According the value of porosity

and permeability in study area, can be conclude as

potential reservoir are only three core (3B, 3C, and 4)

cause has good – very good porosity and permeability.

ACKNOWLEDGMENTS

Authors would say thanks to all of the ﬁeld team,

and also Department of Geological Engineering,

Universitas Islam Riau for giving support for this

study.

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ICoSET 2019 - The Second International Conference on Science, Engineering and Technology