Irene Wallis

Irene Wallis
University of Auckland · School of Environment

BA (Anthropology) MSc (Geology)

About

32
Publications
13,981
Reads
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705
Citations
Citations since 2017
8 Research Items
440 Citations
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2017201820192020202120222023020406080
Introduction
Consultant to geothermal developers and research institutions with over a decade of experience in high-temperature reservoirs. Currently undertaking part-time doctoral research at the University of Auckland that has direct commercial application to the geothermal industry. Their project includes development of open-source python tools for fault/fracture analysis and high-temperature reservoir geomechanics.

Publications

Publications (32)
Conference Paper
Full-text available
We present the results of detail stratigraphic identification of the Bukit Daun geothermal field, Indonesia. This study optimizes the available surface and subsurface data to comprehensively reveal the lithology condition of the field with the regional data that is visualized in the 2D and 3D stratigraphic models. The extensive use of the image log...
Conference Paper
Full-text available
There is a fast-growing inventory of studies on borehole image logs acquired in geothermal reservoirs as more operators elect to deploy this technology. Our contribution to this inventory is to illustrate how judicious use of these data may reveal the geologic controls on permeability. We also provide an open source Python library that enables othe...
Conference Paper
Full-text available
We present results from a study that investigates the geological setting of Bukit Daun geothermal field, Indonesia and how that geology may influence hydrology. Our analysis addresses geologic controls from the regional to the wellbore scale, and incorporates data provided by Pertamina Geothermal Energy with publicly available terrain images and ge...
Article
Full-text available
In geothermal environments, the physical properties of rocks, such as porosity and alteration, are highly variable and control the reservoir's elastic and hydraulic properties. Elastic wave velocity in volcaniclastic rocks and their relation to fractures, pore shapes, and mineral alteration is mostly unknown. We measure ultrasonic P and S wave spee...
Article
Full-text available
The relationships between elastic wave speeds and rock physical properties are commonly studied through laboratory experiments. However, the estimation of elastic wave arrival times and the associated errors are not reported consistently. Changes in experimental conditions such as pressures or fluid substitution vary the arrival time and shape of t...
Article
Full-text available
Fitting the intensity of ensembles of sonic log waveforms with a radiative transfer model allows us to separate scattering from intrinsic attenuation in two wells of the Ngatamariki geothermal field, New Zealand. Independent estimates of scattering and intrinsic attenuation add to the geologic interpretation based on other well log data. Particular...
Conference Paper
Full-text available
Geothermal fluid flow is related to geologic context from the global or district scale down to the reservoir scale. We present a discussion of that relationship that is based on a review of high-temperature geothermal reservoirs worldwide. Initially we focus on large-scale geological controls on productive geothermal reservoirs, such as the role cr...
Conference Paper
Full-text available
The geometry of a geothermal reservoir constrains the exploitable resource volume and the sustainable power capacity. That geometry is typically illustrated by a conceptual model and is primarily defined using a pattern of natural state isotherms. Prior to drilling, surface exploration methods set out to constrain the reservoir geometry even though...
Conference Paper
Full-text available
A reservoir tracer test was conducted at the Ngatamariki Geothermal Field following the commissioning of an 82 MW binary plant in October 2013. The objectives of the test were to assess the fluid flow pathways and potential connections between the injection and production wells. The geothermal fluid is produced from three deep wells in the centre o...
Conference Paper
Full-text available
How does a geologist's concept of permeability differ from that of a reservoir engineer? Permeability is a fundamental question in geothermal resource development, but it's typically discussed through jargon that varies between these two groups of specialists. This paper explores the parameterization of permeability from both perspectives and shows...
Article
Ngatamariki Geothermal Field is the most recently developed field (2013) in the Taupo Volcanic Zone (TVZ) New Zealand for electricity generation. This paper summarises the geological, geophysical and chemistry findings of the last 30 years, and states the current knowledge and understanding of the field. The field, located 17 km northeast Taupo, ex...
Article
The Rotokawa Geothermal Field of New Zealand has seen significant development over the last 20 years and has been the study site for new and innovative geological and geothermal research. This includes the one of the first direct data acquisition and characterisation of subsurface structure and stress properties via borehole image logs, a robust st...
Conference Paper
Full-text available
At the Rotokawa Geothermal Field, the integrated interpretation of microseismic (MEQ) data with other geoscience and reservoir engineering data has helped identify and constrain important elements of the reservoir model, including a major structure that likely influences reservoir fluid flow. MEQ monitoring began when injection moved to deeper well...
Article
Rotokawa geothermal field, Taupo Volcanic Zone (TVZ), New Zealand, has experienced persistent microseismicity since deep injection of condensate and brine began in 2005. Microseismicity is thought to be induced mostly by contraction due to injected fluid, c. 200 °C colder than natural reservoir temperatures, causing a reduction in the normal stress...
Article
Geometric characterisation of a geothermal reservoir's structures, and their relation to stress field orientation, is vital for resource development. Sub-surface structure and stress field orientations of the Rotokawa Geothermal Field, New Zealand have been studied, for the first time, using observations obtained from analysis of three acoustic bor...
Article
Mechanical characterization of hydrothermally altered rocks from geothermal reservoirs will lead to an improved understanding of rock mechanics in a geothermal environment. To characterize rock properties of the selected formations, we prepared samples from intact core for non-destructive (porosity, density and ultrasonic wave velocities) and destr...
Conference Paper
Full-text available
Induced microearthquake (MEQ) activity has been observed at Rotokawa Geothermal Field since deep reinjection began in 2005. Following temporary observations in 2005 and 2006, continuous MEQ recording began in 2008 and continues. A dense network and careful site selection have provided data of sufficient quality to provide constraints for reservoir...
Conference Paper
Full-text available
At the Rotokawa Geothermal Field, the integration of microearthquake (MEQ) data into a space and time visualization of geoscience data has helped identify and constrain important elements of the reservoir model, including a major structure that likely influences reservoir fluid flow. MEQ monitoring began when injection moved to deeper wells in 2006...
Conference Paper
Full-text available
Knowledge of the orientation and magnitude of the principal stresses can be used to model the behavior of faults and fractures, and determine how they may influence fracture hosted permeability in geothermal reservoirs. The permeability of the Rotokawa geothermal reservoir is dominantly fracture hosted and tectonic stresses are largely responsible...
Conference Paper
Full-text available
The Mesozoic basement at Kawerau Geothermal Field comprises well indurated, inter-bedded sandstones and argillites with a complex structural history. These rocks have very low matrix porosity but nonetheless host both geothermal production and injection. Fluid flow therefore is localized in fault and fracture networks. The geometry of, and potentia...
Conference Paper
Full-text available
The Mesozoic basement at Kawerau Geothermal Field comprises well indurated, inter-bedded sandstones and argillites with a complex structural history. These rocks have very low matrix porosity but nonetheless host both geothermal production and injection. Fluid flow therefore is localized in fault and fracture networks. The geometry of, and potentia...
Article
Full-text available
Antarctica is the coldest, driest, and windiest continent on Earth, and contains sand dunes, like deserts elsewhere. The structure and age of the cold climate dunes found in the Victoria Valley, Antarctica, are described in the light of changing climate in the Ross Sea region of Antarctica during the late Holocene. Ground penetrating radar (GPR) wa...
Article
A discontinuous Late Pleistocene pollen record from an eroding coastal cliff section at Henderson Bay on the east coast of Northland, New Zealand, reveals changes in vegetation composition and associated palaeosol development under both stadial and interstadial climatic conditions ascribed to the last interglacial–glacial cycle, probably MIS (Marin...
Article
Short box cores (to 30 cm bsf) and seafloor carbonate grab samples were acquired at mapped hydrocarbon seep sites (600–1200 m water depths) during the 2007 RV SONNE SO191 cruise on the Hikurangi Margin offshore eastern North Island, New Zealand, to evaluate the influence of methane seepage on sedimentologic, biotic, mineralogic and stable isotopic...
Article
The Lower Victoria Valley is one of the McMurdo Dry Valleys, Antarctica, and has the largest concentration of aeolian sand dunes on the continent. Aeolian bedforms include elongate slipfaceless dunes which have been called ‘whaleback’ dunes. These dunes are composed of coarse sand and capped by granule ripples. Ground penetrating radar (GPR) profil...
Article
GPR provides high resolution images of aeolian strata in frozen sand in the McMurdo Dry Valleys of Antarctica. The results have positive implications for potential GPR surveys of aeolian strata on Mars. Within the Lower Victoria Valley, seasonal changes in climate and a topographically-constrained wind regime result in significant wind reversals. A...

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Projects

Projects (2)
Project
To understand the nature of fluid flow within the greywacke basement rocks of New Zealand and its application to geothermal reservoir development.