Silixa’s distributed fibre optic sensing technologies allow for unparalleled capability for characterizing geothermal reservoirs. Our class leading iDAS and ULTIMA DTS systems are readily combined allowing for the maximum amount of insight into the reservoir to be achieved from a single installation. Monitoring solutions can be installed both downhole and at the near surface for either short term geothermal field characterization or for long term asset optimization. Example specific applications of our technology include:

Temperature Characterization

Our ULTIMA™ DTS offers unparalleled resolution performance and can be used to optimize production and maximize geothermal reservoir thermal performance.

Fracture Interconnectivity

Insight into the interconnectivity of permeability between wells can be provided by combining characterization methods based on our distributed sensing technology.

Permeability Enhancement

iDAS and ULTIMA DTS systems can be combined to both guide and monitor permeability enhancement for Enhanced Geothermal Systems (EGS).

Well Field Optimization

Improved utilization of existing infrastructure can be obtained minimizing the necessity for investment in drilling programs.

Active Characterization

Our ULTIMA DTS system can be deployed using an active measurement approach which utilizes response data to determine both reservoir thermal properties and flow distribution.

Key benefits

  • Advanced characterization of geothermal reservoirs
  • Optimization of existing assets
  • Unparalleled measurement capability
  • Improved decision making capacity
  • Suitable for harsh and high temperature environments common in geothermal fields
  • Both high resolution characterization and continuous monitoring capabilities

Reservoir flow heterogeneity can be characterized using both active and passive DTS to optimize geothermal fluid production and injection processes.

How does it work?

Silixa’s fibre optic distributed sensing technologies allow for the collection of data at all locations of up to tens of kilometres of optical fibre simultaneously, transforming both standard and customized cable solutions into the equivalent of thousands of point sensors. This fundamental advance in sensing technology provides a means for characterization of geothermal reservoirs and reservoir processes at spatial and temporal scales that were previously not possible.

Case study: 3D geothermal reservoir characterisation in Nevada, USA

Challenge

To develop and assess an integrated technology for characterizing in three dimensions the mechanical properties of highly heterogeneous fractured rock systems of a geothermal reservoir.

Solution

The solution consisted of deployment of iDAS™ and ULTIMA™ DTS over 9 kilometers of fibre optic cable in a trenched seismic and temperature surface array and 400 meters of fibre optic cable resistant to high temperatures in a downhole array. iDAS and ULTIMA DTS were selected for their revolutionary seismic and extremely fine temperature measurement capabilities, respectively, and for their capacity to be deployed in the harsh conditions experienced in geothermal reservoirs. iDAS was combined with an active seismic source and numerous geophones to carry out a time-lapse seismic survey. Temperature measurements from the ULTIMA DTS were combined with pressure measurements from multiple observation wells. Data were collected during four time intervals each representative of distinct hydraulic conditions due to alterations in the flow field from manipulation in pumping and injection. Collecting time series data under varying hydraulic conditions allows the dataset to be utilized to characterize the hydraulics of the geothermal reservoir through analyses of the poroelastic response.

Results

Both the surface and downhole fiber optic cables installations were completed successfully in late winter 2016. iDAS and ULTIMA DTS data were recorded 24 hours/day over the entire 9400 m of cable for a period of 15 days directly following installation. Analysis of the active and passive seismic data, temperature data, and other data collected is ongoing.

The image on the left shows an ULTIMA DTS temperature profile and iDAS active source seismic data (offset VSP) from the downhole installation at Brady’s Hot Springs. The DTS temperature profile collected during a thermal recovery period indicates that the rock formation has cooled below 262 m due to power plant operations. iDAS active seismic data showcasing cable coupling and P and S wave signal. Temperature and seismic features show correlation as highlighted with blue and red on the plot.

Download the case study here.