DC Resistivity Survey (Mise-A-La-Masse)

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Exploration Technique: DC Resistivity Survey (Mise-A-La-Masse)

Exploration Technique Information
Exploration Group: Geophysical Techniques
Exploration Sub Group: Electrical Techniques
Parent Exploration Technique: Electrical Profiling Configurations
Information Provided by Technique
Lithology: Rock composition, mineral and clay content
Stratigraphic/Structural: Detection of permeable pathways, fracture zones, faults
Hydrological: Resistivity influenced by porosity, grain size distribution, permeability, fluid saturation, fluid type and phase state of the pore water
Thermal: Resistivity influenced by temperature
DC Resistivity Survey (Mise-A-La-Masse):
No definition has been provided for this term.

Use in Geothermal Exploration
The Mise-Á-La-Masse method is normally used for mapping ore deposits with high electrical conductivities such as sulfide bodies. For geothermal exploration the Mise-Á-La-Masse technique can be used to help define the ground fluids that flow into a well. It can also be useful for mapping faults and fractures in a geothermal system and ultimately helps in defining the boundaries of a reservoir. [1]

Field Procedures
This method is a DC resistivity technique in which the charged current electrode (C1) is connected to a conductive structure that goes deep into the surface. The return current electrode (C2) is placed far from the survey area, essentially at infinity. Traditionally this method is used in sulfide ore mining and the positive electrode (C1) is connected to an outcrop of the ore body or an existing borehole within the ore body. [2] In geothermal exploration this method is usually performed by connecting the positive electrode (C1) directly to the casing of an existing well. When a voltage is applied potentials develop which can be measured on the surface and mapped. Electrical potentials are measured using the potential electrode (P1); moving it at incremental distances and radially around the borehole. The fixed potential electrode (P2) is normally placed far from positive current electrode (C1) and usually opposite of the negative current electrode (C2). [3] The shape and size of localized conductive deposits is reflected by the pattern of electrical potentials measured on the surface. [1]

Typical Mise-Á-La-Masse setup and electrode configuration for geothermal exploration.[3]

Potential Pitfalls

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