potencial espontaneo

PERFILAJE GEOFÍSICO DE POZOS
Apunte 3:
Potencial Espontáneo (SP)
CIRCUITO DEL SP
(Rider, M; 1996.)
POTENCIAL DE DIFUCION EN
MEDIOS POROSOS
(Discriminación por tamaño Ion/Catión)
Potencial de difusión
(Rider, M; 1996.)
EL FENOMENO DE SP EN POZOS
POTENCIAL DE CONTACTO DE
LÍQUIDOS (O DE DIFUSIÓN)
POTENCIAL DE MEMBRANA (O DE
LUTITAS)
Potencial de lutitas
(Rider, M; 1996.)
EL FENOMENO DE SP EN POZOS
POTENCIAL DE MEMBRANA
Y TRANSPORTE DE IONES
EL FENOMENO DE SP EN POZOS
POTENCIALO
ELECTROCINETICO
SP ESTATIC0 (SSP): SUMARIO
BOREHOLE PHENOMENON
(Rider, M; 1996.)
(Rider, M; 1996.)
Ejemplo de
perfil de SP
Rmf > Rw
STATIC SP POTENTIAL
(Rider, M; 1996.)
SSP SUMMARY:
Rw from the SP log
• Rw is often known from client information or local knowledge.
• The SP can be used to check the value of Rw or to compute it
when it is unavailable.
• It is especially useful when there are variations of connate
water salinity along the borehole
• SSP = -K log [ Rmfe / Rwe ]
• K is a constant - depending on the temperature.
Kc = 61 + 0.133 ToF
Kc = 65 + 0.24 ToC
(Rider, M; 1996.)
(Schlumberger; 1987.)
(Rider, M; 1996.)
(Doveton, J. H.; 1986.)
(Doveton, J. H.; 1986.)
(Doveton, J. H.; 1986.)
PRACTICAL USES OF SP LOGS
• Differentiate potentially porous and permeable
reservoir rocks from impermeable shales.
• Define bed boundaries.
• Give an indication of shaliness (maximum
deflection is clean sand; minimum is shale).
• Determine Rw in both salt and fresh muds.