To obtain a good estimate of the underground temperature is one of the indispensable tasks of any geothermal development. There are several methods to read the underground temperature (Amerada, thermometer, etc.), but the fluid inclusion thermometry (Fig.3-1) using homogenization temperature of fluid inclusion (Fig.3-2) is a technique with the following advantages.
  • Sub-surface temperatures can be estimated even as well drilling proceeds as far as cuttings are recovered.
  • Compared to other methods, it is possible to estimate the formation temperature of large lost circulation zones that have been subject to cooling because of the inflow of drilling fluids. If such is the case and if geological samples (spot core or cuttings) are obtained, it is possible to estimate the formation temperature with high degree of precision (Fig.3-3).
  • If cores and cuttings are taken and preserved, it is possible to estimate the formation temperature of production or reinjection wells even if temperature surveys were not taken.
  • Through the knowledge of homogenization temperatures, it is possible to estimate not only formation temperatures but also thermodynamic phase of the hydrothermal fluids (Fig.3-4).
Measurement of fluid inclusions is one of the techniques for the analysis of cores and cuttings that West JEC has developed in collaboration with NEDO.

Measurement in fluid inclusions is one of the techniques for the analysis of cores and cuttings that West JEC has developed in collaboration with New Energy Development Organization (NEDO) for many years. Measurements in fluid inclusions are done with the three following purposes.

1) determination of the homogenization temperatures of the fluid inclusions to know subsurface temperature.

2) determination of the ice melting temperature of the fluid inclusions to estimate the salinity of the fluid inclusion.

3) determination, by Laser Raman micro-spectroscopy, of the gas composition of the gaseous components in the fluid inclusions.

West JEC continuously is improving the precision of measurements to develop techniques where the fluid inclusions data is used for constructing a geothermal model.
 
Click to image
Fig.3-1 Classification of fluid inclusion
Fig.3-2 The principle of fluid inclusion thermometry
(Revision of Hayashi and Taguchi, 1982)
Fig.3-3 Example of measurement result of homogenization temperature of fluid inclusion
Fig.3-4 Distribution patterns of homogenization temperature of fluid inclusion in the Hatchobaru geothermal field
Fig.3-5 Equipments for measurements in fluid inclusion

  Back
    Copyright (c) West Japan Engineering Consultants, Inc. All Rights Reserved.