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SELF POTENTIAL (SP). Achmad Y oshi S atriady Muhamad Ha rfan Yusuf H adi. Self Potential Surveying. Introduction This method measures naturally occurring electrical potentials on the ground surface. - PowerPoint PPT Presentation
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SELF POTENTIAL (SP)
Achmad Yoshi SatriadyMuhamad Harfan
Yusuf Hadi
Self Potential Surveying Introduction
This method measures naturally occurring electrical potentials on the ground surface.
The spontaneous or natural potentials developed in the earth by electrochemical actions between minerals and subsurface fluids or by electrokinetic processes involving the flow of ionic fluids.
Basic ConceptElectrofiltration Potential The flow of fluid through a capillary or
porous medium may generate an electrical potential (called the streaming potential) along the flow path
Basic ConceptMineralization Potential
Types of natural electric potential
Types of SP anomalies and their geological source
Field ProcedureFixed-Based ConfigurationDipole Configuration (Gradient
Configuration)
Aplication of Self-Potential Method Detection of Buried TankSelf-potential signals associated with ground water flow
Lokasi Pengukuran Anomali SPDaerah survey
dilakukan di Lebaksiliwangi Sabuga Bandung
Luas daerah pengukuran 14 x 9 m2
Teknik pengukuran yang dipakai Metode Amplitudo Potensial
Pola pengukuranJumlah titik
pengukuran 150 grid
Jarak tiap titik panjang maupun lebarnya sebesar 1 meter, dengan 1 titik acuan tetap
-7
-6
-5
-4
-3
-2
-1
0
1
2
3
4
-10 -5 0 5 10
Kontur Pengukuran Hasil Survey SP
-6 .00 -4 .00 -2 .00 0 .00 2 .0 0 4 .0 0 6 .0 0-6 .00
-4 .00
-2 .00
0 .00
2 .00
-10 .0 m V
-8 .0 m V
-6 .0 m V
-4 .0 m V
-2 .0 m V
0.0 m V
2.0 m V
4.0 m V
6.0 m V
8.0 m V
10 .0 m V
12 .0 m V
14 .0 m V
16 .0 m V
18 .0 m V
20 .0 m V
22 .0 m V
-2 .80-2 .5 0-1 .80-1 .90-2 .30-2 .7 0-3 .80-2 .30-4 .60-5 .60-6 .1 0-4 .90-4 .9 0-5 .10-4 .90
-6 .00 -6 .90 -6 .5 0 -5 .50 -5 .1 0 -4 .20 -3 .40 -2 .20 -1 .90 0 .80 -0 .30 1 .2 0 -0 .50 -1 .1 0 -1 .90
-3 .00-1 .1 02 .401 .4 02.802 .30-1 .20-1 .10-0 .400 .80-1 .4 0-5 .80-3 .7 0-4 .50-4 .90
-4 .50 -4 .30 -0 .4 0 -2 .50 -2 .9 0 0 .40 2 .80 0 .00 7 .20 7 .70 8.60 7 .1 0 8 .90 3 .90 1 .10
-0 .901 .106 .705 .9 013 .007 .006 .405 .200 .60-2 .50-5 .2 0-3 .00-1 .9 0-4 .80-2 .20
-1 .40 -5 .80 -2 .5 0 -4 .80 -1 .1 0 -2 .30 1 .00 -3 .70 -4 .20 -0 .8 0 5.80 7 .7 0 5 .10 -2 .5 0 -10 .60
-3 .500 .2015 .1020 .2 06 .002 .207 .106 .500 .90-5 .0 0-9 .20-6 .9 0-9 .60-4 .50
-8 .80 -7 .30 -6 .9 0 -7 .30 -6 .5 0 3 .00 5 .10 9 .70 20.90 1 6.20 10 .80 21 .3 0 12 .40 7 .30 0 .30
6 .409 .5011 .8013 .3 09.401 0.9014.4013 .709 .307 .204 .9010 .601 0 .8 011 .1011 .7 0
9 .7 0 7 .20 1 0 .7 0 12 .30 13 .10 12 .60 13 .00 10 .50 9 .40 7 .60 8.00 12 .8 0 13 .80 11 .70 7 .20
-6 .00 -4 .00 -2 .00 0 .00 2 .0 0 4 .0 0 6 .0 0-6 .00
-4 .00
-2 .00
0 .00
2 .00
Gambar 3D dari pengukuran SP
-8 .0 m V
-6 .0 m V
-4 .0 m V
-2 .0 m V
0.0 m V
2.0 m V
4.0 m V
6.0 m V
8.0 m V
10 .0 m V
12 .0 m V
14 .0 m V
16 .0 m V
18 .0 m V
20 .0 m V
Hasil kurva anomali kordinat -4 yang di dapat setelah data processing
dari tabel dan grafik disamping diketahui :
V(0) = -2,5 mV xo = -0,122 meter L(xi) = hasil
pengukuran potensial yang dianggap anomaly
q (silinder) = 1 (sesuai referensi menurut Bhatacharya dan Roy) merupakan ordinat posisi yang pada kasus ini posisinya sedikit di geser agar mempermudah perhitungan (dengan menambahkan 4,275)
-15
-10
-5
0
5
10
15
-3 -2 -1 0 1 2 3 4 5
Hasil kurva anomali kordinat -6 yang di dapat setelah data processing
V(0) = -4,3 mV xo = -0,217 meter L(xi) = hasil
pengukuran potensial yang dianggap anomaly
q (silinder) = 1 (sesuai referensi menurut Bhatacharya dan Roy) merupakan ordinat posisi yang pada kasus ini posisinya sedikit di geser agar mempermudah perhitungan (dengan menambahkan 4,18)
-15
-10
-5
0
5
10
15
-3 -2 -1 0 1 2 3 4 5
Hasil survey Besar momen dipol yang didapat berupa
minus, dalam hal ini dapat di asumsikan bahwa kedua anomali merupakan bahan mineral berbahan konduktor, di prediksi ini merupakan sebuah drum.
Self-potential signals associated with ground water flow (infiltration test from a ditch)
Acquisition
Self Potential anomaly expected over water flowing into & out fracture zone
Self Potential anomaly expected over water flowing into fracture zone.
Self Potential anomaly expected over water flowing into fracture zone.
The Measured Self-Potential Signal (measured along profile 3)
The Self-Potential Signal (perpendicular to the ditch)
References
Sharma, Prem V., 2004, Environmental and Engineering Geophysics, Cambridge University Press, UK.
A. Boleve et al., A new formulation to compute self-potential signals associated with ground water flow, 2007, Hydrology and earth System Sciences Discussions.
Putri, Anggun K., Fenomena Self Potential dan Interpretasinya Dengan Metoda least square, 2006, Universitas Negeri Jakarta, Indonesia.