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Investigation of the Rotokawa Geothermal System and Feasibility of Supercritical Fluid Production within the TVZ through Supercritical TOUGH2 Numerical Modeling.

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posted on 08.12.2021, 22:35 by Carson, Benjamin

A single fault process model was created to test the sensitivity of each TOUGH2 rock parameter on the convection flow rate and fluid enthalpy within a simulated fault. With a fixed temperature base the single fault process model found a negative correlation with the fault permeability and convection fluid enthalpy and a positive liner increases in mass flow with fault area.  Next a large scale Supercritical TOUGH2 model was built to simulate the entire Rotokawa geothermal system incorporating findings of the fault process model. The single porosity model 20 x 10 x 6km with 20 layers and 57,600 grid blocks. Unlike previous models of the Rotokawa reservoir and larger scale TVZ numerical models a fixed temperature base with a no flow boundary was used to represent the brittle ductile transition. The model permeability below the currently explored reservoir was bounded by 3-D magnetologic data. Lower resistivity zones were given higher bulk permeability in the model.  The model resulted in a comparable temperature and pressure match to the Rotokawa natural state conditions. Convection of supercritical fluid reached depths shallower than -4500mRL but only occurred in zones with a bulk vertical permeability less than 2 mD. Further modelling work with a supercritical wellbore coupled reservoir model will be need to evaluate the potential deliverability of a super critical well from the Rotokawa geothermal system.

History

Copyright Date

01/01/2020

Date of Award

01/01/2020

Publisher

Te Herenga Waka—Victoria University of Wellington

Rights License

Author Retains Copyright

Degree Discipline

Mathematics

Degree Grantor

Te Herenga Waka—Victoria University of Wellington

Degree Level

Masters

Degree Name

Master of Science

ANZSRC Type Of Activity code

2 STRATEGIC BASIC RESEARCH

Victoria University of Wellington Item Type

Awarded Research Masters Thesis

Language

en_NZ

Victoria University of Wellington School

School of Mathematics and Statistics

Advisors

Mcguinness, Mark; Burnell, John