Predicting Optimal Borehole Locations for Parameter Estimation in Geothermal Reservoirs Using Optimal Experimental Design

Mapping Intimacies ◽

10.5194/egusphere-egu21-12419 ◽

2021 ◽

Author(s):

Johanna Fink ◽

Ralf Seidler

Keyword(s):

Parameter Estimation ◽

Experimental Design ◽

Mathematical Optimization ◽

Simulation Software ◽

Geothermal Reservoir ◽

Temperature Measurements ◽

Optimal Experimental Design ◽

Reservoir Engineering ◽

Hydraulic Permeability ◽

Geothermal Reservoirs

<p>Drilling boreholes during exploration and development of geothermal reservoirs not only involves high cost, but also bears significant risks of failure. In geothermal reservoir engineering, techniques of optimal experimental design (OED) have the potential to improve the decision making process. Previous publications explained the formulation and implementation of this mathematical optimization problem and demonstrated its feasibility for finding borehole locations in two- and three-dimensional reservoir models that minimize the uncertainty of estimating hydraulic permeability of a model unit from temperature measurements. Subsequently, minimizing the uncertainty of the parameter estimation results in a more reliable parametrization of the reservoir simulation, improving the overall process in geothermal reservoir engineering.</p><p>Various OED techniques are implemented in the Environment for Combining Optimization and Simulation Software (EFCOSS). To address problems arising from geothermal modeling, this software framework links mathematical optimization software with SHEMAT-Suite, a geothermal simulation code for fluid flow and heat transport through porous media. This contribution shows how to determine experimental conditions such that the uncertainty when estimating different parameters of model units from temperature measurements in the borehole is minimized. Numerical simulations of synthetic geothermal reservoir scenarios are presented to demonstrate the OED workflow and its applicability to geothermal reservoir modeling</p>

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Complexity analysis and optimal experimental design for parameter estimation of biological systems

2008 Canadian Conference on Electrical and Computer Engineering ◽

10.1109/ccece.2008.4564564 ◽

2008 ◽

Author(s):

Fang-Xiang Wu ◽

Lei Mu ◽

Ruizhi Luo

Keyword(s):

Parameter Estimation ◽

Experimental Design ◽

Complexity Analysis ◽

Biological Systems ◽

Optimal Experimental Design

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Optimal experimental design for the parameter estimation of conduction heated foods

Journal of Food Engineering ◽

10.1016/s0260-8774(00)00142-4 ◽

2001 ◽

Vol 48 (2) ◽

pp. 109-119 ◽

Cited By ~ 21

Author(s):

H.B. Nahor ◽

N. Scheerlinck ◽

R. Verniest ◽

J. De Baerdemaeker ◽

B.M. Nicolaı̈

Keyword(s):

Parameter Estimation ◽

Experimental Design ◽

Optimal Experimental Design

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Numerical Modeling of Fluid Effects on Seismic Properties of Fractured Magmatic Geothermal Reservoirs

10.5194/se-2016-144 ◽

2016 ◽

Author(s):

Melchior Grab ◽

Beatriz Quintal ◽

Eva Caspari ◽

Hansruedi Maurer ◽

Stewart Greenhalgh

Keyword(s):

Numerical Modeling ◽

Velocity Dispersion ◽

Seismic Velocity ◽

Seismic Attenuation ◽

Geothermal Reservoir ◽

Modeling Technique ◽

Hydraulic Permeability ◽

Seismic Properties ◽

Fluid Content ◽

Geothermal Reservoirs

Abstract. Seismic investigations of geothermal reservoirs over the last 20 years have sought to interpret the resulting tomograms and reflection images in terms of the degree of reservoir fracturing and fluid content. Since the former provides the pathways and the latter acts as the medium for transporting geothermal energy, such information is needed to evaluate the quality of the reservoir. In conventional rock physics-based interpretations, this hydro-mechanical information is approximated from seismic velocities computed at the low frequency (field-based) and high frequency (lab-based) limits. In this paper, we demonstrate how seismic properties of fluid-filled, fractured reservoirs can be modeled over the full frequency spectrum using a numerical simulation technique which has become popular in recent years. It is based on Biot's theory of poroelasticity and enables the modeling of the seismic velocity dispersion and the frequency dependent seismic attenuation due to wave-induced fluid flow. These properties are sensitive to key parameters such as the hydraulic permeability of fractures as well as the compressibility and viscosity of the pore fluids. Applying the poroelastic modeling technique to the specific case of a magmatic geothermal system under stress due to the weight of the overlying rocks requires careful parameterization of the model. This includes consideration of the diversity of rock types occurring in the magmatic system and examination of the confining pressure-dependency of each input parameter. After the evaluation of all input parameters, we use our modeling technique to determine the seismic attenuation factors and phase velocities of a rock containing a complex interconnected fracture network, whose geometry is based on a fractured geothermal reservoir in Iceland. Our results indicate that in a magmatic geothermal reservoir the overall seismic velocity structure mainly reflects the lithological heterogeneity of the system, whereas indicators for reservoir permeability and fluid content are deducible from the magnitude of seismic attenuation and the critical frequency at which the peak of attenuation and maximum velocity dispersion occur. The study demonstrates how numerical modeling provides a valuable tool to overcome interpretation ambiguity and to gain a better understanding of the hydrology of geothermal systems, which are embedded in a highly heterogeneous host medium.

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