Developing Australian Enhanced Geothermal Systems and Hot Sedimentary Aquifer Models For Reducing Risk

ABSTRACT Reducing uncertainty at an early stage of resource development is a key necessity to attract project finance. Risk analysis frameworks exist in the petroleum industry for quantifying risk and expected returns At a basic level, any geothermal system comprises two independent components: heat, and a heat transport mechanism. Practically, these translate to temperature, and a heat transfer fluid (or vapor) with a transport pathway (i.e. permeability). Australia has low heat flow relative to 'traditional' geothermal countries, requiring extensive thermal insulation provided by thick sedimentary accumulations in order to reach temperatures high enough for power generation. Because of the depth at which hot reservoirs occur, matrix permeability in sediments is compromised meaning that permeability enhancement is needed for most projects, and exploration is difficult and expensive. Estimating temperature at depth has so far proven to be robust using heat flow or extrapolation of temperature-where such measurements are available. However, these data are sparse. Approaches such as TherMAP The lack of examples of working deep EGS or HSA reservoirs is an outstanding issue. A study is needed to compile the fracture characteristics of existing projects in Australia and internationally. A complementary conceptual study using discrete fracture network modelling in a stochastic sensitivity analysis may provide constraints on the range of geological environments (lithologies, geodynamic history including uplift, compaction, metamorphism, thermal history, previous deformation, present stress regime) favorable for the development of optimal fracture networks for geothermal exploitation. This paper proposes how some of the key parameters around permeability may be derived from proxy data sets, and how modelling using statistical methods may be used in predictive exploration and associated risk analysis

Higher harmonic anisotropic flow measurements of charged particles in Pb-Pb collisions at √sNN=2.76TeV

We report on the first measurement of the triangular nu(3), quadrangular nu(4), and pentagonal nu(5) charged particle flow in Pb-Pb collisions at root s(NN) = 2.76 TeV measured with the ALICE detector at the CERN Large Hadron Collider. We show that the triangular flow can be described in terms of the initial spatial anisotropy and its fluctuations, which provides strong constraints on its origin. In the most central events, where the elliptic flow nu(2) and nu(3) have similar magnitude, a double peaked structure in the two-particle azimuthal correlations is observed, which is often interpreted as a Mach cone response to fast partons. We show that this structure can be naturally explained from the measured anisotropic flow Fourier coefficients

Suppression of high transverse momentum D mesons in central Pb-Pb collisions at root s(NN)=2.76 TeV

The production of the prompt charm mesons D-0, D+, D*(+), and their antiparticles, was measured with the ALICE detector in Pb-Pb collisions at the LHC, at a centre-of-mass energy root s(NN) = 2.76 TeV per nucleon-nucleon collision. The p(t)-differential production yields in the range 2 < p(t) < 16 GeV/c at central rapidity, vertical bar y vertical bar < 0.5, were used to calculate the nuclear modification factor R-AA with respect to a proton-proton reference obtained from the cross section measured at root s = 7 TeV and scaled to root s = 2.76 TeV. For the three meson species, R-AA shows a suppression by a factor 3-4, for transverse momenta larger than 5 GeV/c in the 20% most central collisions. The suppression is reduced for peripheral collisions