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Title: Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir

Abstract

The primary objective of this project was to improve our ability to predict performance of an Enhanced Geothermal System (EGS) reservoir over time by relating, in a quantitative manner, microseismic imaging with fluid and temperature changes within the reservoir. Historically, microseismic data have been used qualitatively to place bounds on the growth of EGS reservoirs created by large hydraulic fracturing experiments. Previous investigators used an experimentally based fracture opening relationship (fracture aperture as a function of pressure), the spatial extent of microseismic events, and some assumptions about fracture frequency to determine the size of an EGS reservoir created during large pumping tests. We addressed a number of issues (1) locating microearthquakes that occur during hydraulic fracturing, (2) obtaining more information about a reservoir than the microearthquake locations from the microearthquake data, for example, information about the seismic velocity structure of the reservoir or the scattering of seismic waves within the reservoir, (3) developing an improved methodology for estimating properties of fractures that intersect wellbores in a reservoir, and (4) developing a conceptual model for explaining the downward growth of observed seismicity that accompanies some hydraulic injections into geothermal reservoirs. We used two primary microseismic datasets for our work. The workmore » was motivated by a dataset from the Salak Geothermal Field in Indonesia where seismicity accompanying a hydraulic injection was observed to migrate downward. We also used data from the Soultz EGS site in France. We also used Vertical Seismic Profiling data from a well in the United States. The work conducted is of benefit for characterizing reservoirs that are created by hydraulic fracturing for both EGS and for petroleum recovery.« less

Authors:
 [1]
  1. Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Publication Date:
Research Org.:
Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
Sponsoring Org.:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Geothermal Technologies Office (EE-4G)
OSTI Identifier:
1351975
Report Number(s):
DOE-MIT-08GO18197
DOE Contract Number:
FG36-08GO18197
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
15 GEOTHERMAL ENERGY; EGS; injection; seismology

Citation Formats

Fehler, Michael. Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir. United States: N. p., 2017. Web. doi:10.2172/1351975.
Fehler, Michael. Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir. United States. doi:10.2172/1351975.
Fehler, Michael. 2017. "Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir". United States. doi:10.2172/1351975. https://www.osti.gov/servlets/purl/1351975.
@article{osti_1351975,
title = {Final Report to DOE EERE – Geothermal Technologies Program Project Title: Monitoring and modeling of fluid flow in a developing enhanced geothermal system (EGS) reservoir},
author = {Fehler, Michael},
abstractNote = {The primary objective of this project was to improve our ability to predict performance of an Enhanced Geothermal System (EGS) reservoir over time by relating, in a quantitative manner, microseismic imaging with fluid and temperature changes within the reservoir. Historically, microseismic data have been used qualitatively to place bounds on the growth of EGS reservoirs created by large hydraulic fracturing experiments. Previous investigators used an experimentally based fracture opening relationship (fracture aperture as a function of pressure), the spatial extent of microseismic events, and some assumptions about fracture frequency to determine the size of an EGS reservoir created during large pumping tests. We addressed a number of issues (1) locating microearthquakes that occur during hydraulic fracturing, (2) obtaining more information about a reservoir than the microearthquake locations from the microearthquake data, for example, information about the seismic velocity structure of the reservoir or the scattering of seismic waves within the reservoir, (3) developing an improved methodology for estimating properties of fractures that intersect wellbores in a reservoir, and (4) developing a conceptual model for explaining the downward growth of observed seismicity that accompanies some hydraulic injections into geothermal reservoirs. We used two primary microseismic datasets for our work. The work was motivated by a dataset from the Salak Geothermal Field in Indonesia where seismicity accompanying a hydraulic injection was observed to migrate downward. We also used data from the Soultz EGS site in France. We also used Vertical Seismic Profiling data from a well in the United States. The work conducted is of benefit for characterizing reservoirs that are created by hydraulic fracturing for both EGS and for petroleum recovery.},
doi = {10.2172/1351975},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 4
}

Technical Report:

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  • This final project report summarizes progress made towards the objectives described in the proposal entitled “Developing New Mathematical Models for Multiphase Flows Based on a Fundamental Probability Density Function Approach”. Substantial progress has been made in theory, modeling and numerical simulation of turbulent multiphase flows. The consistent mathematical framework based on probability density functions is described. New models are proposed for turbulent particle-laden flows and sprays.
  • Summary of the work conducted by the National Geothermal Collaborative (a consensus organization) to identify impediments to geothermal development and catalyze events and dialogues among stakeholders to over those impediments.
  • The goal of this project is to develop, through experimentation and computer modelling, a predictive model for fluid injection enhanced oil recovery methods. Such a model will make possible accurate risk assessment before fluid injection programs are implemented, and therefore help to prevent costly field trial and error. The specific objectives of this study are to: (1) establish the experimental and computational facilities needed to conduct the remaining project objectives, (2) carry out a series of flow-through experiments, collecting data on the effect of T, flow rate, and fluid/solid composition on sample permeability and mineralogy, (3) develop a predictive geochemicalmore » model for mineral reactions which affect reservoir permeability, and (4) test the accuracy of the model using case histories and field tests. The first objective was scheduled for completion during the first project period (2/1/84 through 8/15/84). The tasks for the first project period are discussed in terms of their results and their status with respect to the original project task schedule. All project tasks scheduled for the first year have been completed on or ahead of schedule, with the exception of the testing of the flow-through system. This task will be completed shortly and the experimental portion of the project (objective 2) will soon be underway. 4 references, 1 figure.« less
  • A low-temperature hydrothermal flow-through study was conducted experimentally examine fluid/rock interactions brought about in sandstones as a result of fluid injection enhanced oil recovery (EOR) methods. Such studies will eventually enable the development of a predictive model for fluid injection EOR methods. The design of the low-temperature hydrothermal flow-through system allows the accurate control of fluid flow rate (0.002-10 ml/min), temperature (0 to 300/sup 0/C) and pressure (1 to 500 bar) while flowing fluids through disaggregated solid samples. Samples of St. Peter Sandstone and two different sandstones of the Norphlet Formation from southern Alabama were interacted with distilled, deionized watermore » and a 1% HC1 solution at 250/sup 0/C, 300 bar and 0.1 or 0.5 ml/min fluid flow rate. Solids were analyzed by x-ray powder diffraction and scanning electron microscopy. Fluid samples were analyzed by atomic absorption spectrophotometry and combination pH electrode. A variety of processes which occur in sandstones subjected to fluid injection EOR methods were documented experimentally. Processes damaging to reservoir permeability included iron fouling, silica fouling, migration of clay fines, and precipitation of other secondary phases. Processes resulting in reservoir stimulation involved the dissolution of sandstone framework and/or authigenic mineral constituents. The most successful fluid injection stimulation can be expected for arkosic sandstones containing high percentages of K-feldspar and illite relative to kaolinite, chlorite and smectite, using dilute HCl injection solutions and high fluid flow rates. Fluid chemical data indicate that equilibrium between the solid and injection fluid is not approached for any of the experiments. Therefore, it does not appear that chemical equilibrium computer programs can be used to model these low-temperature reactions. 12 refs., 11 figs., 4 tabs.« less