8/2/2019 03 Permeable Zone Logs SP
1/13
Penilaian Formasi Lanjutan
V 1 - 2006
Per m eab le Zon e Log s
Spontaneous Potential (SP) Log
R. Widijanto
September 29, 2006
8/2/2019 03 Permeable Zone Logs SP
2/13
2
V 1 - 2006
Agenda
Permeable Zone Logs
Basic Principle of Spontaneous Potential (SP)
Log1. Spontaneous Potential (SP) Log
2. SP Curve
Interpretation of Spontaneous Potential (SP)Log
1. Computation Rw From SP
8/2/2019 03 Permeable Zone Logs SP
3/13
3
V 1 - 2006
Permeable Zone Logs
1. Permeable Zones
Sands
Carbonate
2. Log used:
Spontaneous Potential (SP) Log (electrical measurement)
Gamma ray (GR) Logs (nuclear measurement)
8/2/2019 03 Permeable Zone Logs SP
4/13
4
V 1 - 2006
Basic Principle of Spontaneous Potential (SP) Log
1. Spontaneous Potential (SP) Log
SP Log is recording of the different in electrical potential between afixed electrode at the surface and a movable electrode in theborehole
Hole must be filled with conductive mud
No SP can be measured in
Oil-based mud
Empty holes
Cased holes
Scale in millivolts
2. SP curve is used to:1. Select permeable zones
2. Provide Rw values
3. Estimate the degree of shalines of reservoir rock
8/2/2019 03 Permeable Zone Logs SP
5/13
5
V 1 - 2006
Spontaneous Potential Curve
Limited to water-basedmud systems.
8/2/2019 03 Permeable Zone Logs SP
6/13
6
V 1 - 2006
SP Measurement
N
The SP is
measurementagainst depthof the potentialdifference
between thevoltage in thewellbore and anelectrode at thesurface
8/2/2019 03 Permeable Zone Logs SP
7/13
7
V 1 - 2006
SP Current Flow
The strength and direction ofthe current loop is dependenton the relative resistivities ofthe formation and the filtrate
SP
millvolts
Ek = Electrokinetic
Ej = Liquid JunctionEm= Membrane
8/2/2019 03 Permeable Zone Logs SP
8/13
8
V 1 - 2006
Salinity effects on the SP
The primary SP responseis due to the relativesalinities between themud filtrate and theformation fluids
Reverse SP Rw > RmfReverse SP Rw > Rmf
Normal SP Rw < RmfNormal SP Rw < Rmf
8/2/2019 03 Permeable Zone Logs SP
9/13
9
V 1 - 2006
Effect of bed thickness and resistivity on curve shape
R
8/2/2019 03 Permeable Zone Logs SP
10/13
10
V 1 - 2006
Shape of SP
Shape and amplitude controlled by:
relative resistivity of fluids
resistivity of the formation(hydrocarbons, porosity)
permeability
bed thickness
clay type and content
hydrocarbon suppression
tight streak
8/2/2019 03 Permeable Zone Logs SP
11/13
11
V 1 - 2006
Interpretation of Spontaneous Potential (SP) Log
1. Total Potential, SSP
2. Calculate Rw
1. Equations
2. Charts
8/2/2019 03 Permeable Zone Logs SP
12/13
12
V 1 - 2006
Resources
The Society of Petrophysicists and Well LogAnalysts: www.spwla.org
Society of Petroleum Engineers: www.spe.orgFormation Evaluation:http://www.spe.org/spe/jsp/basic/0,,1104_1714_1
003934,00.html
Schlumberger Interpretation Chart: www.slb.com
orhttp://content.slb.com/Hub/Docs/connect/reference/Chartbook/
http://www.spe.org/spe/jsp/basic/0,,1104_1714_1003934,00.htmlhttp://www.spe.org/spe/jsp/basic/0,,1104_1714_1003934,00.htmlhttp://www.slb.com/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://www.slb.com/http://www.spe.org/spe/jsp/basic/0,,1104_1714_1003934,00.htmlhttp://www.spe.org/spe/jsp/basic/0,,1104_1714_1003934,00.html8/2/2019 03 Permeable Zone Logs SP
13/13
13
V 1 - 2006
Question?
http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/http://content.slb.com/Hub/Docs/connect/reference/Chartbook/Top Related