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.

Calculations of self‐potential anomalies near vertical contacts

Geophysics ◽  
1979 ◽  
Vol 44 (2) ◽  
pp. 195-205 ◽  
Author(s):  
David V. Fitterman
Keyword(s):  
Physical Mechanism ◽  
Chemical Potential ◽  
Source Region ◽  
Streaming Potential ◽  
Source Mechanism ◽  
Constant Intensity ◽  
Potential Gradients ◽  
Vertical Contact ◽  
Chemical Potential Gradients ◽  
Self Potential

The self‐potential anomalies due to streaming potential effects in the vicinity of a vertical contact are analyzed. This approach is different from most previous studies in that the source is tied to a specific physical mechanism instead of arbitrarily selected charge distributions or current sources. The analysis is valid for any source mechanism that can be thought of in terms of crosscoupled flows, e.g., the thermoelectric effect or chemical potential gradients. The anomalies tend to be antisymmetric across the contact with the magnitude of the anomaly being larger on the more resistive side of the contact. An analytic expression for the case of a constant intensity, rectangular source is derived from the general solution. The anomalies for this simple case are computable with a handheld calculator and can be used to estimate the location, extent, and magnitude of the anomaly source region. With this information it is possible to determine the most probable crosscoupling source mechanism.

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.

Heavy metal sources and anthropogenic enrichment in the environment around the Cerro Prieto Geothermal Field, Mexico

Geothermics ◽  
2018 ◽  
Vol 72 ◽  
pp. 170-181 ◽  
Author(s):  
Z.I. González-Acevedo ◽  
M.A. García-Zarate ◽  
E.A. Núñez-Zarco ◽  
B.I. Anda-Martín
Keyword(s):  
Heavy Metal ◽  
Geothermal Field ◽  
Metal Sources ◽  
Cerro Prieto ◽  
Heavy Metal Sources

scholarly journals CCN measurements at the Princess Elisabeth Antarctica Research Station during three austral summers

2018 ◽  
Author(s):  
Paul Herenz ◽  
Heike Wex ◽  
Alexander Mangold ◽  
Quentin Laffineur ◽  
Irina V. Gorodestkaya ◽  
...  
Keyword(s):  
Southern Ocean ◽  
Aerosol Particle ◽  
Aerosol Particles ◽  
Source Region ◽  
Austral Summer ◽  
Research Station ◽  
Air Masses ◽  
Potential Source ◽  
The Antarctic ◽  
Aitken Mode

Abstract. For three austral summer seasons (2013–2016, each from December to February) aerosol particles arriving at the Belgian Antarctic research station Princess Elisabeth (PE), in Dronning Maud Land in East Antarctica were characterized in terms of number concentrations of total aerosol particles (NCN) and cloud condensation nuclei (NCCN), the particle number size distribution (PNSD), the aerosol particle hygroscopicity and the influence of the air mass origin on NCN and NCCN. In general NCN was found to range from 40 to 6700 cm−3 with a median of 333 cm−3, while NCCN was found to cover a range between less than 10 and 1300 cm−3 for supersaturations (SS) between 0.1 and 0.7 %. It is shown that the aerosol is Aitken mode dominated and is characterized by a significant amount of freshly, secondarily formed aerosol particles, with 94 % and 36 % of the aerosol particles are smaller than 90 nm and ≈ 35 nm, respectively. Measurements of the basic meteorological parameters as well as the history of the air masses arriving at the measurement station indicate that the station is influenced by both, continental air masses originating from the Antarctic inland ice sheet (continental events – CE) and marine air masses originating from the Southern Ocean (marine events – ME). CEs came along with rather constant NCN and NCCN values, which we denote to be Antarctic continental background concentrations. MEs however cause large fluctuations in NCN and NCCN caused by scavenging due to precipitation or new particle formation based on marine precursors. The application of Hysplit back trajectories in form of the potential source contribution function (PSCF) analysis indicate, that the region of the Southern Ocean is a potential source of Aitken mode particles. For particles larger than ≈ 110 nm (CCN measured at SS of 0.1 %) the Antarctic ice shelf regions were found to be a potential source region, most likely due to the emission of sea salt aerosol particles, released from snow particles from surface snow layers by sublimation, e.g., during periods of high wind speed, leading to drifting or blowing snow. On the basis of the PNSDs and NCCN, the critical diameter for cloud droplet activation and the aerosol particle hygroscopicity parameter κ were determined to be 110 nm and 1, respectively, for a SS of 0.1 %. The region of the Antarctic inland plateau however was not found to feature a significant source region for CN and CCN measured at the PE station in austral summer.

THE CERRO PRIETO GEOTHERMAL FIELD, MEXICO

2007 ◽  
pp. 165-197 ◽  
Author(s):  
Harsh Gupta ◽  
Sukanta Roy
Keyword(s):  
Geothermal Field ◽  
Cerro Prieto

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.

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