REPORT ON SOIL RESISTIVITY AT UP-GRADING / MODIFICATION FACILITY OF INJECTION AIR PILOT WATERFLOOD, RANTAU FIELD, KECAMATAN RANTAU, KABUPATEN ACEH TAMIANG, PROVINCE OF NAD

REPORT ON

SOIL RESISTIVITY

AT UP-GRADING / MODIFICATION FACILITY OF INJECTION AIR PILOT WATERFLOOD, RANTAU FIELD,

 KECAMATAN RANTAU, KABUPATEN ACEH TAMIANG,

PROVINCE OF NAD

CHAPTER I. INTRODUCTION

1.1.The General Information

This report contains the results of soil resistivityat up-grading / modification facility of injection air pilot waterflood       pipe line on RantauOil Field, Kabupaten Aceh Tamiang, theProvinceof NAD.

The proposed of survey is to investigate value of resistivity layer for underground beds design  based on the obtained information and data collected. A total 9 ofsoil resistivityhave been carried out on the location.The field work activity was done from the 20^ft of April 2011to 21^th of April 2011.

The analyses and writing report were one week afterward. The information obtained from the soil resistivity data, the geological condition  and theliteratures.Those all materialshad been contributed for preparing this report.

The soil resistivity carried out with the Wenner four pin methods on the site as shown on Figure 1.The data collected and interpretation of resistivity layer shown on Appendix 1 and 2. The interpretation of resistivity data was used the software IPI2Win from Dept. of Geophysics ,Geological Faculty, Moscow State University.

1.2. The Purpose of Investigation

The purpose of soil resistivitywas to define the soil resistivity characteristics of the subsurface with emphasis on determining the near-surface characteristics. This information would then be available for possible use in the design of ground beds for a cathodic protection system. The data of soil resistivity and the soil resistivity graphic shown on the Appendix 1 and 2.

1.3. TheEquipments

The equipment has been used for investigation are:

1. Resistivity Meter Naniura NRD 300 HF, made by Mr. Marpaung, officer of PusatSumberDayaGeologi, Bandung, Indonesia.
2. GPS eTrex H Garmin
3. Geology compast MERIDIAN. Switzerland
4. 4 stainless steel electrodes
5. 4 cables a’ 50 m and 50 m measure tapes.
6. Camera Mpixs 3.1. Megapxel

1.4. The Scope of Works

The soil resistivity is done with Wenner electrodes arangementas shown on the Fig.1. The four pin consists of 4 electrodes with using the Wenner array of a spacing of 1, 1.5, 2.0 3. 5. 7. 10, 12, 15, 20, 25 and 30m to make current penetration up to 30 meter depth. The result of soil resistivity for ground bed design and soil resistivity graphic are described on Chapter 3.

Figure 1. Wenner four pin method for measuring soil resistivity

CHAPTER 2. TOPOGRAPHY AND GEOLOGY

2.1.Topography         

The area is located on the elevation among 10 ma.s.l to 30 m a.s.l.. In general, the region is flat shape.  The SR 01 located on the excavation area of PPP.Rantau. Five (5) resistivity point located on the east of PPP Rantau. SR 02 located on W.I.P AlurBamban. SR 03 and SR 04 closed to Sungai Tamiang.

The all location of soil resistivity closed to oil well location.

2.2.Geology

The area located on the map of the geology of Langsa Quadrangle scale 1: 250.000, Sumatra. The geological description is done by Cameron N.R., et.all. , 1981.

The oldest rock is Kluet Formation of Perm Carbon (Puk) rock which is located on the south of map sheet. The young formation is Unnamed Superficial Deposits and Fluviatile (Qh) of Holocene. 

The Rantau Oil Field area covered by Unnamesupervisial deposits, coastal and fluviatil (Qh) and Idi Formation (Qpi). Underneath of  those formation is Seureula (Tps). Unnamesupervicial deposits, coastal danfluviatil  is consist gravels, sands and clays. The Idi Formation (Qpi) which is consisting of semi consolidated sands, gravels and clays. Seureula Formation (Tps) is consist of rhythmics sandstone and  mudstone.

The geological map of investigation and surrounding area shown on the Fig. 2. The geological map adopted from the Bennett, J.D. et.all, 1981.

Figure 3.The geological Map of Langsa Quadrangle, Sumatra (after, Bennett, J.D. et.all, 1981 Scale 1: 250.000

CHAPTER 3. THE RESULTS OF INVESTIGATION

3.1. The Basic of Interpretation

The soil resistivity is a function of soil moisture and the concentration of ionic soluble salts and is considered to ne most comprehensive indicator of a soil’s corrosivity. Typically, the lower the resistivity, the higher will be corrosively as indicated in a following Table. The corosivity rating is based on reference of Pierre R. Roberge (2006).

Table 1. Corrosivity ratings based on soil resistivity.

Soil resistivity (ohm – m )	Corrosivity Rating
> 200	Essentially non-corrosive
100 – 200	Mildly corrosive
50 – 100	Moderately corrosive
30 – 50	Corrosive
10 – 30	Highly corrosive
< 10	Extremely corrosive

The soil resistivity is measured with Wenner four pin methods as shown on Figure 1.

The interpretation for groundwater resistivity used with software of IPI2Win. The software is made by Dept. of Geophysics, Geological Faculty, Moscow State University  in year of 2000.

3.1. The Soil Resistivity

Location map of soil resistivity is shown on Figure 3. The soil resistivity data and soil resistivity graphic are shown on Appendix 1 and 2. The data of soil resistivity has been plotted for soil resistivity graphic.

Generally, the upper section indicated the high resistivity  from depth of (a) = 1,1,5.2,and 3m.  On the lower part indicated middle resistivity and low resistivity from depth of (a) = 5,7,10, 12,15,20,25 and 30 m.

The result of soil resistivity for ground bed design would be used the average resistivity value from (a) = 1 m to (a) = 3 m.The value of average resistivity for ground bed design is shown on Table 2.

Table 2. The result of soil resistivity

No. No. Depths (a) Average Resistivity (ohm-m)  for ground bed design Corrosivity Rating 1 SR 01 1 m  to 3m 92.2 Moderately corrosive 2 SR 02 1 m  to 3m 71.73 Moderately corrosive 3 SR 03 1 m  to 3m 50.61 Moderately corrosive 4 SR 04 1 m  to 3m 523.81 Essentially non corrosive 5 SR 05 1 m  to 3 m 22.85 Higly corrosive 6 SR 06 1 m  to 3 m 77.53 Moderately corrosive 7 SR 07 1 m  to 3m 81.48 Moderately corrosive 8 SR 08 1 m  to 3 m 8.01 Extremely corrosive 9 SR 09 1 m  to 3 m 82.68 Moderately  corrosive

The interpretation of resistivity curve has been done with using the IP12Win. The result of interpretation represented with assumed of soil types, resistivity layer, resistivity value and corrosivity rating. The result of interpretation of curve is shown on Table 3.

Table 3. Result of interpretation resistivity curve using the IPI2Win.

No.	Point	Depth (meter)	Resistivity Value(ohm-m)	Presumptive Soil type	Corrosivity rating	Depth of Soil excavation
1	SR 01	0.0             - 0.50 0.50 – 2.28 2.28 – 13.00 > 13.00	667 47.60 5.16 4470	Clay soil Sandy soil Clay Gravel	Ess. noncorrosive Corrosive Highly corrosive Ess.non corrosive	3 m with cathodic protection.
2	SR 02	0.0             -2.46 2.46 – 9.50 > 9.50	73.37 62.17 16.81	Clay soil Sandy soil Sandy clay	Moderately corr Moderately corr Highly corrosive	3 m with cathodic protection.
3	SR 03	0.0             – 0.81 0.81 – 1.48 1.48 – 3.38 3.38 – 8.5 > 8.5	96 13 141 4.96 4112	Clay soil Clay Sand Clay Gravel	Moderately corr Highly corrosive Mildy corrosive Extremly corr. Ess.non corrosive	3 m with cathodic protection.
4	SR 04	0.0             – 0.5 0.5 – 0.51 > 0.51	631.5 1.57 51.6	Compact. soil Clay Sand	Ess. noncorrosive Extremely corr. Moderately corr.	3 m with cathodic protection
5	SR 05	0.0             – 0.5 0.5 – 0.51 0.51 – 2.63 2.63 – 8.49 > 8.49	227 0.04 36.8 0.9 733	Compact. soil Clay Sand Clay Gravel	Ess. noncorrosive Extremely corr. Corrosive Extremely corr. Ess. noncorrosive	3 m with cathodic protection
6	SR 06	0.0             – 0.5 0.5 – 8.64 > 8.64	128 68.5 261	Compacct.Soil Sand Gravel	Mildly corr. Moderately corr. Ess. noncorrosive	3 m with cathodic protection
7	SR 07	0.0             – 0.6 0.6 – 3.0 3.0 – 6.7 6.70 – 15.0 >15.0	278.9 49.92 4.3 48.45 636	Compact.soil Sand Clay Sand Gravel	Ess..noncorrosive Corrosive Extremely corr. Corrosive Ess.noncorrosive	3 m with cathodic protection
8	SR 08	0.90-0.6 0.6 – 1.3 1.3 – 3 3 – 15.64 >15.64	8.6 3.8 34.83 4.7 8.2	Clay Clay Sand Clay Clay	Extremely corr. Extremely corr. Corrosive Extremely corr. Extremely corr.	3 m with cathodic protection
9	SR 09	0.0             – 1.1 1.1             – 4.04 4.04 – 26.8 > 26.8	162 23.2 126 51	Compact. soil Sandy clay Gravel Sand	Mildly corr. Highly corr. Mildly corr. Moderately corr.	3 m with cathodic protection

CHAPTER 4. DISCUSSION

1.     The soil resistivity graphic indicated that average resistivity for groundbed to 3 m varied between 50.00 ohm-m to 100 ohm-m. However, exception at SR 05 and SR 08with 22.85 ohm-m nd 8.01 ohm-m. The corrosivity rating are moderately corrosive except at SR 05 and SR 08 which is highly corrosive and extremely corrosive.

2.     The interpretation of resistivity curve indicated that layer consist of brown soil, clay, sand and gravel at the various depth. The clay layer indicated the low resistivity and extremely corrosive.  The sand layer indicated middle resistivity with resistivity around 40 ohm-m to 100 ohm-m with corrosive and mildly corrosive.

CHAPTER 5. CONCLUSIONS AND RECOMMENDATION

The average soil resistivity for ground bed design can be used as shown on the Table 1. The average soil resistivity has been calculated on (a) 1 m to 3 m.The all sounding point indicated moderately corrosive with exception at SR 04, SR 05  and SR 08 with corrosivity rating essentially .non corrosive, corrosive and extremely corrosive.

It recommended that to buried pipe should using cathodic protection up to depth of 3 m. 

REFERENCES

1. Bemmelen, van R.W., 1949, The Geology of Indonesia General Geology. Volume 1 A. The Hague, MartinusNijhoff.
2. Orellana and Mooney, 1966, the Master Tables and Curves for Vertical Electrical Sounding over Layered Structures, Intercienca, Madrid.
3. Bennett J.D. et.all1981, Geological Map of the LangsaQuadrangle, Sumatra, Lembar (Quadrangle) : LANGSA -0420 Scale 1 : 250.000., P3G, GRDC
4. Ir. Masdjuri and Ir.Suryaman, 1989, SurveiPotensiAirtanah Daerah LhokseumawedanSekitarnya, Daerah Istimewa Aceh. Laporan N.26/HGKA/1989, DitjenGeologidan SDM, Dit GTL, Sub DitHidrogeologi, DepartemenPertambangandanEnergi.
5. Roberge, P.R.,2006, CORROSION BASICS, An Introduction, Second Edition, NAFE International Publication Committee.

Software:

IPI2Win, Interpretation of geoelectricdata from Dept. Geophysics, Geological Faculty, Moscow State University.

LAMPIRAN 1

(APPANDIX 1)

DATA LAPANGAN ASLI

(FIELD DATA SHEET ORIGINAL)

LAMPIRAN 4

(APPANDIX 4)

FOTO KEGIATAN LAPANGAN

(PHOTOS OF FIELD ACTIVITY)

Photo 1.  SR 01 at PPP Rantau

 

Photo 2. SR 02 at W.I.P Alure Bamban

Photo 3. SR 03 on the eastern part of river.

Photo 4. SR 04 closed to S. Tamiang

Photo 5. SR 05 above the pipeline on the west of Sanggar Pramuka

Photo 6. SR 6 at the south of golf field.

Photo 7. SR 07 at the eastern of golf field.

Photo 8. SR 08 closed to Well R 130.

Photo 9. SR 09 closed to Well R 117

 REPORT ON

SOIL RESISTIVITY

AT UP-GRADING / MODIFICATION FACILITY OF INJECTION AIR PILOT WATERFLOOD, RANTAU FIELD,

 KECAMATAN RANTAU, KABUPATEN ACEH TAMIANG,

PROVINCE OF NAD

CHAPTER I. INTRODUCTION

1.1.The General Information

This report contains the results of soil resistivityat up-grading / modification facility of injection air pilot waterflood       pipe line on RantauOil Field, Kabupaten Aceh Tamiang, theProvinceof NAD.

The proposed of survey is to investigate value of resistivity layer for underground beds design  based on the obtained information and data collected. A total 9 ofsoil resistivityhave been carried out on the location.The field work activity was done from the 20^ft of April 2011to 21^th of April 2011.

The analyses and writing report were one week afterward. The information obtained from the soil resistivity data, the geological condition  and theliteratures.Those all materialshad been contributed for preparing this report.

The soil resistivity carried out with the Wenner four pin methods on the site as shown on Figure 1.The data collected and interpretation of resistivity layer shown on Appendix 1 and 2. The interpretation of resistivity data was used the software IPI2Win from Dept. of Geophysics ,Geological Faculty, Moscow State University.

1.2. The Purpose of Investigation

The purpose of soil resistivitywas to define the soil resistivity characteristics of the subsurface with emphasis on determining the near-surface characteristics. This information would then be available for possible use in the design of ground beds for a cathodic protection system. The data of soil resistivity and the soil resistivity graphic shown on the Appendix 1 and 2.

1.3. TheEquipments

The equipment has been used for investigation are:

1. Resistivity Meter Naniura NRD 300 HF, made by Mr. Marpaung, officer of PusatSumberDayaGeologi, Bandung, Indonesia.
2. GPS eTrex H Garmin
3. Geology compast MERIDIAN. Switzerland
4. 4 stainless steel electrodes
5. 4 cables a’ 50 m and 50 m measure tapes.
6. Camera Mpixs 3.1. Megapxel

1.4. The Scope of Works

The soil resistivity is done with Wenner electrodes arangementas shown on the Fig.1. The four pin consists of 4 electrodes with using the Wenner array of a spacing of 1, 1.5, 2.0 3. 5. 7. 10, 12, 15, 20, 25 and 30m to make current penetration up to 30 meter depth. The result of soil resistivity for ground bed design and soil resistivity graphic are described on Chapter 3.

Figure 1. Wenner four pin method for measuring soil resistivity

CHAPTER 2. TOPOGRAPHY AND GEOLOGY

2.1.Topography         

The area is located on the elevation among 10 ma.s.l to 30 m a.s.l.. In general, the region is flat shape.  The SR 01 located on the excavation area of PPP.Rantau. Five (5) resistivity point located on the east of PPP Rantau. SR 02 located on W.I.P AlurBamban. SR 03 and SR 04 closed to Sungai Tamiang.

The all location of soil resistivity closed to oil well location.

2.2.Geology

The area located on the map of the geology of Langsa Quadrangle scale 1: 250.000, Sumatra. The geological description is done by Cameron N.R., et.all. , 1981.

The oldest rock is Kluet Formation of Perm Carbon (Puk) rock which is located on the south of map sheet. The young formation is Unnamed Superficial Deposits and Fluviatile (Qh) of Holocene. 

The Rantau Oil Field area covered by Unnamesupervisial deposits, coastal and fluviatil (Qh) and Idi Formation (Qpi). Underneath of  those formation is Seureula (Tps). Unnamesupervicial deposits, coastal danfluviatil  is consist gravels, sands and clays. The Idi Formation (Qpi) which is consisting of semi consolidated sands, gravels and clays. Seureula Formation (Tps) is consist of rhythmics sandstone and  mudstone.

The geological map of investigation and surrounding area shown on the Fig. 2. The geological map adopted from the Bennett, J.D. et.all, 1981.

Figure 3.The geological Map of Langsa Quadrangle, Sumatra (after, Bennett, J.D. et.all, 1981 Scale 1: 250.000

CHAPTER 3. THE RESULTS OF INVESTIGATION

3.1. The Basic of Interpretation

The soil resistivity is a function of soil moisture and the concentration of ionic soluble salts and is considered to ne most comprehensive indicator of a soil’s corrosivity. Typically, the lower the resistivity, the higher will be corrosively as indicated in a following Table. The corosivity rating is based on reference of Pierre R. Roberge (2006).

Table 1. Corrosivity ratings based on soil resistivity.

Soil resistivity (ohm – m )	Corrosivity Rating
> 200	Essentially non-corrosive
100 – 200	Mildly corrosive
50 – 100	Moderately corrosive
30 – 50	Corrosive
10 – 30	Highly corrosive
< 10	Extremely corrosive

The soil resistivity is measured with Wenner four pin methods as shown on Figure 1.

The interpretation for groundwater resistivity used with software of IPI2Win. The software is made by Dept. of Geophysics, Geological Faculty, Moscow State University  in year of 2000.

3.1. The Soil Resistivity

Location map of soil resistivity is shown on Figure 3. The soil resistivity data and soil resistivity graphic are shown on Appendix 1 and 2. The data of soil resistivity has been plotted for soil resistivity graphic.

Generally, the upper section indicated the high resistivity  from depth of (a) = 1,1,5.2,and 3m.  On the lower part indicated middle resistivity and low resistivity from depth of (a) = 5,7,10, 12,15,20,25 and 30 m.

The result of soil resistivity for ground bed design would be used the average resistivity value from (a) = 1 m to (a) = 3 m.The value of average resistivity for ground bed design is shown on Table 2.

Table 2. The result of soil resistivity

No. No. Depths (a) Average Resistivity (ohm-m)  for ground bed design Corrosivity Rating 1 SR 01 1 m  to 3m 92.2 Moderately corrosive 2 SR 02 1 m  to 3m 71.73 Moderately corrosive 3 SR 03 1 m  to 3m 50.61 Moderately corrosive 4 SR 04 1 m  to 3m 523.81 Essentially non corrosive 5 SR 05 1 m  to 3 m 22.85 Higly corrosive 6 SR 06 1 m  to 3 m 77.53 Moderately corrosive 7 SR 07 1 m  to 3m 81.48 Moderately corrosive 8 SR 08 1 m  to 3 m 8.01 Extremely corrosive 9 SR 09 1 m  to 3 m 82.68 Moderately  corrosive

The interpretation of resistivity curve has been done with using the IP12Win. The result of interpretation represented with assumed of soil types, resistivity layer, resistivity value and corrosivity rating. The result of interpretation of curve is shown on Table 3.

Table 3. Result of interpretation resistivity curve using the IPI2Win.

No.	Point	Depth (meter)	Resistivity Value(ohm-m)	Presumptive Soil type	Corrosivity rating	Depth of Soil excavation
1	SR 01	0.0             - 0.50 0.50 – 2.28 2.28 – 13.00 > 13.00	667 47.60 5.16 4470	Clay soil Sandy soil Clay Gravel	Ess. noncorrosive Corrosive Highly corrosive Ess.non corrosive	3 m with cathodic protection.
2	SR 02	0.0             -2.46 2.46 – 9.50 > 9.50	73.37 62.17 16.81	Clay soil Sandy soil Sandy clay	Moderately corr Moderately corr Highly corrosive	3 m with cathodic protection.
3	SR 03	0.0             – 0.81 0.81 – 1.48 1.48 – 3.38 3.38 – 8.5 > 8.5	96 13 141 4.96 4112	Clay soil Clay Sand Clay Gravel	Moderately corr Highly corrosive Mildy corrosive Extremly corr. Ess.non corrosive	3 m with cathodic protection.
4	SR 04	0.0             – 0.5 0.5 – 0.51 > 0.51	631.5 1.57 51.6	Compact. soil Clay Sand	Ess. noncorrosive Extremely corr. Moderately corr.	3 m with cathodic protection
5	SR 05	0.0             – 0.5 0.5 – 0.51 0.51 – 2.63 2.63 – 8.49 > 8.49	227 0.04 36.8 0.9 733	Compact. soil Clay Sand Clay Gravel	Ess. noncorrosive Extremely corr. Corrosive Extremely corr. Ess. noncorrosive	3 m with cathodic protection
6	SR 06	0.0             – 0.5 0.5 – 8.64 > 8.64	128 68.5 261	Compacct.Soil Sand Gravel	Mildly corr. Moderately corr. Ess. noncorrosive	3 m with cathodic protection
7	SR 07	0.0             – 0.6 0.6 – 3.0 3.0 – 6.7 6.70 – 15.0 >15.0	278.9 49.92 4.3 48.45 636	Compact.soil Sand Clay Sand Gravel	Ess..noncorrosive Corrosive Extremely corr. Corrosive Ess.noncorrosive	3 m with cathodic protection
8	SR 08	0.90-0.6 0.6 – 1.3 1.3 – 3 3 – 15.64 >15.64	8.6 3.8 34.83 4.7 8.2	Clay Clay Sand Clay Clay	Extremely corr. Extremely corr. Corrosive Extremely corr. Extremely corr.	3 m with cathodic protection
9	SR 09	0.0             – 1.1 1.1             – 4.04 4.04 – 26.8 > 26.8	162 23.2 126 51	Compact. soil Sandy clay Gravel Sand	Mildly corr. Highly corr. Mildly corr. Moderately corr.	3 m with cathodic protection

CHAPTER 4. DISCUSSION

1.     The soil resistivity graphic indicated that average resistivity for groundbed to 3 m varied between 50.00 ohm-m to 100 ohm-m. However, exception at SR 05 and SR 08with 22.85 ohm-m nd 8.01 ohm-m. The corrosivity rating are moderately corrosive except at SR 05 and SR 08 which is highly corrosive and extremely corrosive.

2.     The interpretation of resistivity curve indicated that layer consist of brown soil, clay, sand and gravel at the various depth. The clay layer indicated the low resistivity and extremely corrosive.  The sand layer indicated middle resistivity with resistivity around 40 ohm-m to 100 ohm-m with corrosive and mildly corrosive.

CHAPTER 5. CONCLUSIONS AND RECOMMENDATION

The average soil resistivity for ground bed design can be used as shown on the Table 1. The average soil resistivity has been calculated on (a) 1 m to 3 m.The all sounding point indicated moderately corrosive with exception at SR 04, SR 05  and SR 08 with corrosivity rating essentially .non corrosive, corrosive and extremely corrosive.

It recommended that to buried pipe should using cathodic protection up to depth of 3 m. 

REFERENCES

1. Bemmelen, van R.W., 1949, The Geology of Indonesia General Geology. Volume 1 A. The Hague, MartinusNijhoff.
2. Orellana and Mooney, 1966, the Master Tables and Curves for Vertical Electrical Sounding over Layered Structures, Intercienca, Madrid.
3. Bennett J.D. et.all1981, Geological Map of the LangsaQuadrangle, Sumatra, Lembar (Quadrangle) : LANGSA -0420 Scale 1 : 250.000., P3G, GRDC
4. Ir. Masdjuri and Ir.Suryaman, 1989, SurveiPotensiAirtanah Daerah LhokseumawedanSekitarnya, Daerah Istimewa Aceh. Laporan N.26/HGKA/1989, DitjenGeologidan SDM, Dit GTL, Sub DitHidrogeologi, DepartemenPertambangandanEnergi.
5. Roberge, P.R.,2006, CORROSION BASICS, An Introduction, Second Edition, NAFE International Publication Committee.

Software:

IPI2Win, Interpretation of geoelectricdata from Dept. Geophysics, Geological Faculty, Moscow State University.

LAMPIRAN 1

(APPANDIX 1)

DATA LAPANGAN ASLI

(FIELD DATA SHEET ORIGINAL)

LAMPIRAN 4

(APPANDIX 4)

FOTO KEGIATAN LAPANGAN

(PHOTOS OF FIELD ACTIVITY)

Photo 1.  SR 01 at PPP Rantau

 

Photo 2. SR 02 at W.I.P Alure Bamban

Photo 3. SR 03 on the eastern part of river.

Photo 4. SR 04 closed to S. Tamiang

Photo 5. SR 05 above the pipeline on the west of Sanggar Pramuka

Photo 6. SR 6 at the south of golf field.

Photo 7. SR 07 at the eastern of golf field.

Photo 8. SR 08 closed to Well R 130.

Photo 9. SR 09 closed to Well R 117

 REPORT ON

SOIL RESISTIVITY

AT UP-GRADING / MODIFICATION FACILITY OF INJECTION AIR PILOT WATERFLOOD, RANTAU FIELD,

 KECAMATAN RANTAU, KABUPATEN ACEH TAMIANG,

PROVINCE OF NAD

CHAPTER I. INTRODUCTION

1.1.The General Information

This report contains the results of soil resistivityat up-grading / modification facility of injection air pilot waterflood       pipe line on RantauOil Field, Kabupaten Aceh Tamiang, theProvinceof NAD.

The proposed of survey is to investigate value of resistivity layer for underground beds design  based on the obtained information and data collected. A total 9 ofsoil resistivityhave been carried out on the location.The field work activity was done from the 20^ft of April 2011to 21^th of April 2011.

The analyses and writing report were one week afterward. The information obtained from the soil resistivity data, the geological condition  and theliteratures.Those all materialshad been contributed for preparing this report.

The soil resistivity carried out with the Wenner four pin methods on the site as shown on Figure 1.The data collected and interpretation of resistivity layer shown on Appendix 1 and 2. The interpretation of resistivity data was used the software IPI2Win from Dept. of Geophysics ,Geological Faculty, Moscow State University.

1.2. The Purpose of Investigation

The purpose of soil resistivitywas to define the soil resistivity characteristics of the subsurface with emphasis on determining the near-surface characteristics. This information would then be available for possible use in the design of ground beds for a cathodic protection system. The data of soil resistivity and the soil resistivity graphic shown on the Appendix 1 and 2.

1.3. TheEquipments

The equipment has been used for investigation are:

1. Resistivity Meter Naniura NRD 300 HF, made by Mr. Marpaung, officer of PusatSumberDayaGeologi, Bandung, Indonesia.
2. GPS eTrex H Garmin
3. Geology compast MERIDIAN. Switzerland
4. 4 stainless steel electrodes
5. 4 cables a’ 50 m and 50 m measure tapes.
6. Camera Mpixs 3.1. Megapxel

1.4. The Scope of Works

The soil resistivity is done with Wenner electrodes arangementas shown on the Fig.1. The four pin consists of 4 electrodes with using the Wenner array of a spacing of 1, 1.5, 2.0 3. 5. 7. 10, 12, 15, 20, 25 and 30m to make current penetration up to 30 meter depth. The result of soil resistivity for ground bed design and soil resistivity graphic are described on Chapter 3.

Figure 1. Wenner four pin method for measuring soil resistivity

CHAPTER 2. TOPOGRAPHY AND GEOLOGY

2.1.Topography         

The area is located on the elevation among 10 ma.s.l to 30 m a.s.l.. In general, the region is flat shape.  The SR 01 located on the excavation area of PPP.Rantau. Five (5) resistivity point located on the east of PPP Rantau. SR 02 located on W.I.P AlurBamban. SR 03 and SR 04 closed to Sungai Tamiang.

The all location of soil resistivity closed to oil well location.

2.2.Geology

The area located on the map of the geology of Langsa Quadrangle scale 1: 250.000, Sumatra. The geological description is done by Cameron N.R., et.all. , 1981.

The oldest rock is Kluet Formation of Perm Carbon (Puk) rock which is located on the south of map sheet. The young formation is Unnamed Superficial Deposits and Fluviatile (Qh) of Holocene. 

The Rantau Oil Field area covered by Unnamesupervisial deposits, coastal and fluviatil (Qh) and Idi Formation (Qpi). Underneath of  those formation is Seureula (Tps). Unnamesupervicial deposits, coastal danfluviatil  is consist gravels, sands and clays. The Idi Formation (Qpi) which is consisting of semi consolidated sands, gravels and clays. Seureula Formation (Tps) is consist of rhythmics sandstone and  mudstone.

The geological map of investigation and surrounding area shown on the Fig. 2. The geological map adopted from the Bennett, J.D. et.all, 1981.

Figure 3.The geological Map of Langsa Quadrangle, Sumatra (after, Bennett, J.D. et.all, 1981 Scale 1: 250.000

CHAPTER 3. THE RESULTS OF INVESTIGATION

3.1. The Basic of Interpretation

The soil resistivity is a function of soil moisture and the concentration of ionic soluble salts and is considered to ne most comprehensive indicator of a soil’s corrosivity. Typically, the lower the resistivity, the higher will be corrosively as indicated in a following Table. The corosivity rating is based on reference of Pierre R. Roberge (2006).

Table 1. Corrosivity ratings based on soil resistivity.

Soil resistivity (ohm – m )	Corrosivity Rating
> 200	Essentially non-corrosive
100 – 200	Mildly corrosive
50 – 100	Moderately corrosive
30 – 50	Corrosive
10 – 30	Highly corrosive
< 10	Extremely corrosive

The soil resistivity is measured with Wenner four pin methods as shown on Figure 1.

The interpretation for groundwater resistivity used with software of IPI2Win. The software is made by Dept. of Geophysics, Geological Faculty, Moscow State University  in year of 2000.

3.1. The Soil Resistivity

Location map of soil resistivity is shown on Figure 3. The soil resistivity data and soil resistivity graphic are shown on Appendix 1 and 2. The data of soil resistivity has been plotted for soil resistivity graphic.

Generally, the upper section indicated the high resistivity  from depth of (a) = 1,1,5.2,and 3m.  On the lower part indicated middle resistivity and low resistivity from depth of (a) = 5,7,10, 12,15,20,25 and 30 m.

The result of soil resistivity for ground bed design would be used the average resistivity value from (a) = 1 m to (a) = 3 m.The value of average resistivity for ground bed design is shown on Table 2.

Table 2. The result of soil resistivity

No. No. Depths (a) Average Resistivity (ohm-m)  for ground bed design Corrosivity Rating 1 SR 01 1 m  to 3m 92.2 Moderately corrosive 2 SR 02 1 m  to 3m 71.73 Moderately corrosive 3 SR 03 1 m  to 3m 50.61 Moderately corrosive 4 SR 04 1 m  to 3m 523.81 Essentially non corrosive 5 SR 05 1 m  to 3 m 22.85 Higly corrosive 6 SR 06 1 m  to 3 m 77.53 Moderately corrosive 7 SR 07 1 m  to 3m 81.48 Moderately corrosive 8 SR 08 1 m  to 3 m 8.01 Extremely corrosive 9 SR 09 1 m  to 3 m 82.68 Moderately  corrosive

The interpretation of resistivity curve has been done with using the IP12Win. The result of interpretation represented with assumed of soil types, resistivity layer, resistivity value and corrosivity rating. The result of interpretation of curve is shown on Table 3.

Table 3. Result of interpretation resistivity curve using the IPI2Win.

No.	Point	Depth (meter)	Resistivity Value(ohm-m)	Presumptive Soil type	Corrosivity rating	Depth of Soil excavation
1	SR 01	0.0             - 0.50 0.50 – 2.28 2.28 – 13.00 > 13.00	667 47.60 5.16 4470	Clay soil Sandy soil Clay Gravel	Ess. noncorrosive Corrosive Highly corrosive Ess.non corrosive	3 m with cathodic protection.
2	SR 02	0.0             -2.46 2.46 – 9.50 > 9.50	73.37 62.17 16.81	Clay soil Sandy soil Sandy clay	Moderately corr Moderately corr Highly corrosive	3 m with cathodic protection.
3	SR 03	0.0             – 0.81 0.81 – 1.48 1.48 – 3.38 3.38 – 8.5 > 8.5	96 13 141 4.96 4112	Clay soil Clay Sand Clay Gravel	Moderately corr Highly corrosive Mildy corrosive Extremly corr. Ess.non corrosive	3 m with cathodic protection.
4	SR 04	0.0             – 0.5 0.5 – 0.51 > 0.51	631.5 1.57 51.6	Compact. soil Clay Sand	Ess. noncorrosive Extremely corr. Moderately corr.	3 m with cathodic protection
5	SR 05	0.0             – 0.5 0.5 – 0.51 0.51 – 2.63 2.63 – 8.49 > 8.49	227 0.04 36.8 0.9 733	Compact. soil Clay Sand Clay Gravel	Ess. noncorrosive Extremely corr. Corrosive Extremely corr. Ess. noncorrosive	3 m with cathodic protection
6	SR 06	0.0             – 0.5 0.5 – 8.64 > 8.64	128 68.5 261	Compacct.Soil Sand Gravel	Mildly corr. Moderately corr. Ess. noncorrosive	3 m with cathodic protection
7	SR 07	0.0             – 0.6 0.6 – 3.0 3.0 – 6.7 6.70 – 15.0 >15.0	278.9 49.92 4.3 48.45 636	Compact.soil Sand Clay Sand Gravel	Ess..noncorrosive Corrosive Extremely corr. Corrosive Ess.noncorrosive	3 m with cathodic protection
8	SR 08	0.90-0.6 0.6 – 1.3 1.3 – 3 3 – 15.64 >15.64	8.6 3.8 34.83 4.7 8.2	Clay Clay Sand Clay Clay	Extremely corr. Extremely corr. Corrosive Extremely corr. Extremely corr.	3 m with cathodic protection
9	SR 09	0.0             – 1.1 1.1             – 4.04 4.04 – 26.8 > 26.8	162 23.2 126 51	Compact. soil Sandy clay Gravel Sand	Mildly corr. Highly corr. Mildly corr. Moderately corr.	3 m with cathodic protection

CHAPTER 4. DISCUSSION

1.     The soil resistivity graphic indicated that average resistivity for groundbed to 3 m varied between 50.00 ohm-m to 100 ohm-m. However, exception at SR 05 and SR 08with 22.85 ohm-m nd 8.01 ohm-m. The corrosivity rating are moderately corrosive except at SR 05 and SR 08 which is highly corrosive and extremely corrosive.

2.     The interpretation of resistivity curve indicated that layer consist of brown soil, clay, sand and gravel at the various depth. The clay layer indicated the low resistivity and extremely corrosive.  The sand layer indicated middle resistivity with resistivity around 40 ohm-m to 100 ohm-m with corrosive and mildly corrosive.

CHAPTER 5. CONCLUSIONS AND RECOMMENDATION

The average soil resistivity for ground bed design can be used as shown on the Table 1. The average soil resistivity has been calculated on (a) 1 m to 3 m.The all sounding point indicated moderately corrosive with exception at SR 04, SR 05  and SR 08 with corrosivity rating essentially .non corrosive, corrosive and extremely corrosive.

It recommended that to buried pipe should using cathodic protection up to depth of 3 m. 

REFERENCES

1. Bemmelen, van R.W., 1949, The Geology of Indonesia General Geology. Volume 1 A. The Hague, MartinusNijhoff.
2. Orellana and Mooney, 1966, the Master Tables and Curves for Vertical Electrical Sounding over Layered Structures, Intercienca, Madrid.
3. Bennett J.D. et.all1981, Geological Map of the LangsaQuadrangle, Sumatra, Lembar (Quadrangle) : LANGSA -0420 Scale 1 : 250.000., P3G, GRDC
4. Ir. Masdjuri and Ir.Suryaman, 1989, SurveiPotensiAirtanah Daerah LhokseumawedanSekitarnya, Daerah Istimewa Aceh. Laporan N.26/HGKA/1989, DitjenGeologidan SDM, Dit GTL, Sub DitHidrogeologi, DepartemenPertambangandanEnergi.
5. Roberge, P.R.,2006, CORROSION BASICS, An Introduction, Second Edition, NAFE International Publication Committee.

Software:

IPI2Win, Interpretation of geoelectricdata from Dept. Geophysics, Geological Faculty, Moscow State University.

LAMPIRAN 1

(APPANDIX 1)

DATA LAPANGAN ASLI

(FIELD DATA SHEET ORIGINAL)

LAMPIRAN 4

(APPANDIX 4)

FOTO KEGIATAN LAPANGAN

(PHOTOS OF FIELD ACTIVITY)

Photo 1.  SR 01 at PPP Rantau

 

Photo 2. SR 02 at W.I.P Alure Bamban

Photo 3. SR 03 on the eastern part of river.

Photo 4. SR 04 closed to S. Tamiang

Photo 5. SR 05 above the pipeline on the west of Sanggar Pramuka

Photo 6. SR 6 at the south of golf field.

Photo 7. SR 07 at the eastern of golf field.

Photo 8. SR 08 closed to Well R 130.

Photo 9. SR 09 closed to Well R 117