Exploration Technique: Microgravity-Hybrid Microgravity
|Exploration Technique Information|
|Exploration Group:||Geophysical Techniques|
|Exploration Sub Group:||Gravity Techniques|
|Parent Exploration Technique:||Gravity Techniques|
|Information Provided by Technique|
|Stratigraphic/Structural:||Ground subsidence can be mapped using microgravity|
|Hydrological:||Monitoring net mass changes of a geothermal reservoir due to production and reinjection processes|
|Thermal:||Changes in liquid density due to temperature changes in the reservoir|
|Low-End Estimate (USD):|| 50.00|
5,000 centUSD/ station
|Median Estimate (USD):|| 61.67|
6,167 centUSD/ station
|High-End Estimate (USD):|| 115.00|
11,500 centUSD/ station
|Low-End Estimate:|| 0.30 days|
8.213552e-4 years/ 10 stn
|Median Estimate:|| 0.36 days|
9.856263e-4 years/ 10 stn
|High-End Estimate:|| 1.20 days|
0.00329 years/ 10 stn
|Cost/Time Dependency:||Location, Size, Resolution, Terrain, Weather|
- "The intent of a microgravity survey at a geothermal field is to understand net mass changes of the geothermal reservoir over time. The changes in gravity are caused by: vertical ground movement (mainly subsidence); changes in shallow groundwater levels; liquid drawdown or saturation changes in the two-phase zone; and changes in liquid density resulting from temperature changes. Vertical ground movement and shallow groundwater levels need to be surveyed separately using GPS and shallow well data and corrected for in the microgravity survey to obtain net mass change. '"`UNIQ--ref-00000000-QINU`"'
Microgravity surveys produce contour maps of gravity changes, through which regions of net mass loss or gain can be identified over a specified time period in between measurements.For instance, at the Wairakei geothermal field in New Zealand, the ground subsidence achieved a maximum vertical ground movement of 11 m in one area of the field. Additionally, the maximum subsidence rate (in mm/yr) between gravity measurements may be calculated. '"`UNIQ--ref-00000001-QINU`"'" cannot be used as a page name in this wiki.
- The given value was not understood.
Microgravity surveys produce contour maps of gravity changes, through which regions of net mass loss or gain can be identified over a specified time period in between measurements.
For instance, at the Wairakei geothermal field in New Zealand, the ground subsidence achieved a maximum vertical ground movement of 11 m in one area of the field. Additionally, the maximum subsidence rate (in mm/yr) between gravity measurements may be calculated. 
• Microgravity measurements should be recorded outside the boundary of the known geothermal field as well in order to characterize the fluid flow upon reinjection.
• The frequency of reoccupation of the microgravity stations should be greater during the initial production of the field, when the largest changes may be anticipated.
• Microgravity data should be applied in conjunction with numerical reservoir simulation models. 
No exploration activities found.