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Spontaneous potential log, commonly called the self potential log or SP log, is a passive measurement taken by oil industry well loggers to characterise rock formation properties. The log works by measuring small electric potentials (measured in millivolts) between depths with in the borehole and a grounded electrode at the surface.
The total electrochemical potential is thus summarized as E C = E M + E J = K log 10 (a w /a mf) Since spontaneous potential is a measure of electrochemical potential and the ionic activity of a solution is inversely proportional to its resistivity, the above equation can be simplified as SP = E C = K log 10 (R mfe /R we), where R mfe and R we ...
The Spontaneous Potential (SP) log measures the natural or spontaneous potential difference between the borehole and the surface, without any applied current. It was one of the first wireline logs to be developed, found when a single potential electrode was lowered into a well and a potential was measured relative to a fixed reference electrode ...
The SP log, known variously as a "Spontaneous Potential", "Self Potential" or "Shale Potential" log is a voltmeter measurement of the voltage or electrical potential difference between the mud in the hole at a particular depth and a copper ground stake driven into the surface of the earth a short distance from the borehole.
The terms measurement while drilling (MWD), and logging while drilling (LWD) are not used consistently throughout the industry. Although these terms are related, within the context of this section, the term measurement while drilling refers to directional-drilling measurements, e.g. for decision support for the wellbore path, (Inclination and ...
Logging while drilling (LWD) is a technique of conveying well logging tools into the well borehole downhole as part of the bottom hole assembly (BHA).. Although the terms Measurement while drilling (MWD) and LWD are related, within the context of this section, the term MWD refers to directional-drilling measurements, e.g., for decision support for the smooth operation of the drilling, while ...
Electrical techniques, including electrical resistivity tomography, induced polarization and spontaneous potential. Electromagnetic methods, such as magnetotellurics, ground penetrating radar and transient/time-domain electromagnetics. Borehole geophysics, also called well logging. Remote sensing techniques, including hyperspectral imaging.
Electrical techniques, including electrical resistivity tomography, induced polarization, spontaneous potential and marine control source electromagnetic (mCSEM) or EM seabed logging. [2] This type of survey is carried out mainly to study the existence of groundwater.