GEOTHERMAL EXPLORATION

Exploration stage is a very important step to begin the geothermal development. The target of exploration is to increase the drilling success ratio, hence the integrated science and technology are needed to assess the resources. PT NewQuest Geotechnology offers the following services for geothermal exploration and other application:

GEOLOGY

Geological exploration is the first step of the preliminary reconnaissance. The objective of geological exploration is to identify the surface manifestation (i.e. fumaroles, thermal springs, steaming ground, mud pools and geysers) in the geothermal prospect area. These geothermal manifestations is plotted in the geological map, completed with geological structures.

Related to the geological investigation, PT NewQuest Geotechnology offers these following services:

  • Remote Sensing Interpretation
  • Structure Interpretation
  • Regional Geology
  • Hydrogeology Setting
  • Geomorphology
  • Volcano – Tectonic Evolution
  • Geological Mapping
  • Dating of Rock
  • Stratigraphy
  • Geological Conceptual Model

GEOCHEMISTRY

Chemical contain data of a hot spring steam discharges on the virgin area, can gives us very useful information that can lead to determine the further exploration from the area. Supported by geological data, this geochemical data can be the guidance to make a recommendation for subsurface exploration. Chemical geothermometer related to the fluid chemistry and the temperature of the reservoir, become the common method used to assess the energy potential from the geothermal prospect area.

These are the methods offered:

  • Sampling and Analysis of Water Geochemistry
  • Sampling and Analysis of Gas Geochemistry
  • Sampling and Analysis of Isotope Geochemistry
  • Chemical Geothermometry
  • Chemical Hydrogeology
  • Tracer Test
  • Injection Strategy
  • Geochemical Conceptual Model

GEOPHYSICS

The subsurface image acquired from geophysical data is very important to the exploration stage. The the surface manifestation found from the geological and geochemisty data can be confirmed to the subsurface condition by analyzing physical parameters, such as: resistivity, density, and magnetic susceptibility from the geophysical data.

Subsurface resistivity data gives the very important information about the geothermal system image. The components that assemble the geothermal system such as: heat source, reservoir, and clay cap, also the fault indication can be distinguished from the resistivity. Alteration process controlled by the temperature and fluide also having the corelation to the resistivity. So, the subsurface resistivity data can help to map the locatioan and the size of geothermal reservoir.

The density of subsurface rock acquired from gravity data gives the information of the intrusion existence, regional geological structure, etc. From the magnetic data, the alteration caused by demagnetization of rock can be mapped.

The conceptual model made from the integration of geoscientific (geology, geochemistry and geophysics) data can help to illustrate the geothermal system and to define the well trajectory and potency assessment.

PT NewQuest Geotechnology provides geophysical survey services, such as:

  1. MT/TDEM survey
  2. Gravity survey
  3. MEQ survey

3-D MODELLING OF GEOSCIENTIFIC DATA

PT NewQuest Geotechnology, in collaboration with Geothermal Laboratory The University of Indonesia, develops software named GeoSlicer-X used to 3-D modeling. All type of data can be inputed to this software if have the coordinate data (x, y, z) and value data (in form of resistivity, temperature, pressure, etc). The 3-D visualization illustrate the subsurface condition clearly, so it can be very helping for the interpretation.

The 3-D data that can be visualized are:

  • Magnetotelluric
  • Micro Earthquake
  • Resistivity
  • Induces Polarization
  • Gravity
  • CSAMT
  • Mise – A – La – Masse
  • Well Trajectory
  • Fracture Zone
  • Fault Zone
  • Reservoir Modeling
  • Lithology
  • Pressure Distribution
  • Temperature Distribution
  • Potential Assessment
  • Permeability Distribution
  • Any 3-D Available Data

RESERVOIR SIMULATION

The data acquired using geoscientific survey (i.e. geophysics, geology, and geochemistry), supported by exploration well data, is evaluated and then simulated to predict the potency and the reserve that can be producted, also how long will the geothermal field can produce steam.

RESERVOIR MONITORING

During the exploration phase, reservoir is in the dynamic condition. Many changes happened during the production process and fluide reinjection are being conducted. All of the possibilities can happen, i.e. reservoir decline, which is caused by many factors. Here, the monitoring is urgently needed to observe the changed of reservoir. Therefore the stability of production can be controlled.

The monitoring can be conducted by two methods, they are:

  1. Micro earthquake monitoring : with the purpose of monitor the fracture pattern using micro-earthquake event that generated by fluid flow from injection well to confirm whether the re-injection process was accurate or still need more adjustment
  2. Microgravity monitoring : in order to monitor the mass transfer caused by production and re-injection of geothermal fluid

FEASIBILITY STUDY

PT NewQuest Geotechnology also provide the service of feasibility study to assess the geothermal prospect area.