Self potential (SP) measurement in the geothermal field of Penantian and Airkelinsar Village, Pasemah Airkeruh District, Empat Lawang Regency, South Sumatra Province

2021 ◽  
Author(s):  
Alexander Yosep Elake ◽  
Frinsyah Virgo ◽  
Pieldrie Nanlohy
Keyword(s):  
Geothermal Field ◽  
Self Potential

RESISTIVITY, SELF‐POTENTIAL, AND INDUCED‐POLARIZATION SURVEYS OF A VAPOR‐DOMINATED GEOTHERMAL SYSTEM

Geophysics ◽  
1973 ◽  
Vol 38 (6) ◽  
pp. 1130-1144 ◽  
Author(s):  
A. A. R. Zohdy ◽  
L. A. Anderson ◽  
L. J. P. Muffler
Keyword(s):  
Geothermal Field ◽  
Induced Polarization ◽  
Hot Water ◽  
Thermal Waters ◽  
Geothermal System ◽  
Electrical Soundings ◽  
Lateral Extent ◽  
High Concentrations ◽  
Lake Deposits ◽  
Self Potential

The Mud Volcano area in Yellowstone National Park provides an example of a vapor‐dominated geothermal system. A test well drilled to a depth of about 347 ft penetrated the vapor‐dominated reservoir at a depth of less than 300 ft. Subsequently, 16 vertical electrical soundings (VES) of the Schlumberger type were made along a 3.7‐mile traverse to evaluate the electrical resistivity distribution within this geothermal field. Interpretation of the VES curves by computer modeling indicates that the vapor‐dominated layer has a resistivity of about 75–130 ohm‐m and that its lateral extent is about 1 mile. It is characteristically overlain by a low‐resistivity layer of about 2–6.5 ohm‐m, and it is laterally confined by a layer of about 30 ohm‐m. This 30‐ohm‐m layer, which probably represents hot water circulating in low‐porosity rocks, also underlies most of the survey at an average depth of about 1000 ft. Horizontal resistivity profiles, measured with two electrode spacings of an AMN array, qualitatively corroborate the sounding interpretation. The profiling data delineate the southeast boundary of the geothermal field as a distinct transition from low to high apparent resistivities. The northwest boundary is less distinctly defined because of the presence of thick lake deposits of low resistivities. A broad positive self‐potential anomaly is observed over the geothermal field, and it is interpretable in terms of the circulation of the thermal waters. Induced‐polarization anomalies were obtained at the northwest boundary and near the southeast boundary of the vapor‐dominated field. These anomalies probably are caused by relatively high concentrations of pyrite.

Inversion of self‐potential data from the Cerro Prieto geothermal field, Mexico

Geophysics ◽  
1982 ◽  
Vol 47 (6) ◽  
pp. 938-945 ◽  
Author(s):  
David V. Fitterman ◽  
Robert F. Corwin
Keyword(s):  
Source Region ◽  
Geothermal Field ◽  
Reservoir Rock ◽  
Coupling Coefficients ◽  
Vertical Extent ◽  
Potential Source ◽  
Cerro Prieto ◽  
Vertical Contact ◽  
Self Potential ◽  
Production Zone

Self‐potential (SP) data from the Cerro Prieto geothermal field in Baja California, Mexico have been inverted using a model consisting of a vertical contact separating regions of different electrical properties. A temperature source is assumed to coincide with the vertical contact between materials with different thermoelectric coupling coefficients. A derivative‐free Levenberg‐Marquardt algorithm is used to estimate values for the depth, vertical extent, length, and intensity of the source region. The depth to the top of the source is estimated to be about 1.3 ± 0.2 km, which agrees quite well with the depth to the top of the production zone determined from drilling. The vertical extent and length of the source region are estimated to be 11 ± 3 km and 9.9 ± 0.4 km, respectively. There appears to be geologic evidence for the presence of a fault or fault zone within the geothermal field that roughly coincides in location with the self‐potential source region. The conductivity on the east side of the production zone is estimated to be 80 percent of the value to the west, which is in general agreement with field resistivity measurements. Thermoelectric coupling coefficients measured in the laboratory on samples of reservoir rock are not large enough to explain the −340 ± 40 mV source intensity predicted by the model, possibly because the laboratory measurements were made at temperatures about 300°C lower than the reservoir value. These results do not rule out the possibility of a streaming potential source mechanism.

Interpretation of self-potential survey results from the East Mesa Geothermal Field, California

1981 ◽  
Vol 86 (B3) ◽  
pp. 1841 ◽  
Author(s):  
Robert F. Corwin ◽  
Gregory T. DeMoully ◽  
Richard S. Harding ◽  
H. F. Morrison
Keyword(s):  
Geothermal Field ◽  
Survey Results ◽  
Self Potential

Self-potential studies at the cerro prieto geothermal field

Geothermics ◽  
1980 ◽  
Vol 9 (1-2) ◽  
pp. 39-47 ◽  
Author(s):  
R.F. Corwin ◽  
H.F. Morrison ◽  
S. Diaz C. ◽  
J. Rodriguez B.
Keyword(s):  
Geothermal Field ◽  
Cerro Prieto ◽  
Self Potential

Thermoelectrical self‐potential anomalies and their relationship to the solid angle subtended by the source region

Geophysics ◽  
1984 ◽  
Vol 49 (2) ◽  
pp. 165-170 ◽  
Author(s):  
David V. Fitterman
Keyword(s):  
Weighting Function ◽  
Solid Angle ◽  
Source Region ◽  
Geothermal Field ◽  
Observation Point ◽  
Constant Intensity ◽  
Self Potential ◽  
Sp Anomaly

The calculation of self‐potential (SP) anomalies produced by thermoelectric sources is shown to be equivalent to calculating the weighted solid angle subtended at the observation point by the source region and its images where the weighting function is the source intensity. This interpretation provides an easy way of visualizing the effect of different source geometries, and describes the nonuniqueness associated with SP sources. For example, changes in a model which keep the product of source intensity and area constant do not appreciably change the produced anomaly. Similarly, deepening a source requires an increase of source intensity or size to produce the same anomaly. When conductivity contrasts become small or nonexistent, the number of image sources becomes finite or zero, respectively, further simplifying the calculation. As an example, the SP anomaly of a dipping rectangular source of constant intensity is computed using the method. This model is applied to SP data from the East Mesa geothermal field.

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