Field data and 222Rn activities from the Altona well field. 222Rn, the most stable isotope of radon, was tested for during well extraction experiments. Tracers were also tracked to monitor the well. Data include 222Rn activities and complimentary geochemical data for multiple field experiments as part of an EGS project.

Analysis of Unit Mobility Ratio Well-to-Well Tracer Flow to Determine Reservoir Heterogeneity DOE/SF/11564-1

Caldwell Ranch Exploration and Confirmation Project, Northwest Geysers, CA: 2011 Geothermal Technologies Peer Review Project Summary The Caldwell Ranch Exploration and Confirmation Project was to drill, test, and confirm the present economic viability of the undeveloped geothermal reservoir in the Caldwell Ranch area. The objective of the project was to re-open and re-complete three wells abandoned in 1999 and 2000: Prati 5 (P-5), Prati 14 (P-14) and Prati 38 (P-38). The data and information collection included: (1) drilling and geology of the subject wells; (2) reservoir production flow rates, temperature, pressure, thickness, permeability, and rock fluid chemistry using new innovative combinations technologies and (3) a determination of present reservoir conditions in order to determine the feasibility of re-developing a steam supply.

Due the high temperature and pressure conditions found in geothermal wells, tracer studies designed to elucidate properties of geothermal reservoirs are traditionally conducted by pulling liquid samples from the wellhead. These samples are then sent off for analysis in a fixed laboratory setting. Unfortunately by pulling the sample from the surface, information regarding the depth of the fractures generating the tracer flow is lost. Additionally, significant time is lost in sending the samples off for traditional chemical analysis. This presentation focuses on our efforts to develop downhole high temperature and pressure stable ion selective electrodes capable of measuring the concentration of tracers used in geothermal studies, along with pH, at various depths in the wellbore creating tracer concentration and pH depth profiles for use in geothermal reservoir analysis.

The EGS Collab SIGMA-V project is a multi-lab and university collaborative research project that is being undertaken at the Sanford Underground Research Facility (SURF) in South Dakota. The project consists of studying stimulation, fluid-flow, and heat transfer processes at a scale of 10-20 m, which is readily amenable to detailed characterization and monitoring. One objective of the project is to establish circulation from injector to producer by hydraulically fracturing the injector. Data generated during these experiments is to be compared with predictions from coupled thermal, hydrological, mechanical, and chemical simulators. One such a simulator, TOUGH2-CSM, has been enhanced in order to simulate EGS Collab SIGMA-V project experiments. These modifications include adding tracers, the capability to model tracer sorption, and an embedded fracture formulation. A set of example problems validate our conservative tracer transport and sorption formulations. We then simulated tracer transport and thermal breakthrough for the first EGS Collab SIGMA-V experiment. This dataset includes the TOUGH2-CSM input and output files associated with the thermal and tracer simulations. A conference paper is included for additional context.

This submission contains the presentation slides and recordings from the first 98 EGS Collab Modeling and Simulation Working Group teleconferences. These teleconferences served three objectives for the project: 1) share simulation results, 2) communicate field activities and results to the simulation teams, and 3) hold open scientific discussions on EGS topics.

This package includes data and models that support hydraulic fracture stimulation and fluid circulation experiments in the Sanford Underground Research Facility (SURF). A paper by Schwering et al. (2020) describes the deterministic basis for developing a "common" discrete fracture network (CDFN) model of significant natural fractures in EGS Collab Testbed 1 on the 4850-Level of SURF. The ReadMe for this model shows drift, wells, scanlines, fracture data, interpreted fractures, and geophysical visualizations. There is also a summary of the data that was used in this experiment and includes results from reviewing core, televiewer (TV) logs, core-TV depth/feature registration, and from mapping weeps in the 4850-Level drift. The CDFN is intended to be a baseline model of the pre-stimulated testbed (though some observations from stimulation helped inform the model).

This file contains the first set of tracer data for the EGS Collab testbed. The first set of tracer tests were conducted during October-November, 2018. We have included tracer data for C-dots, chloride, fluorescein, and rhodamine-B. The details about the tracer test can be found in Background and Methods of Tracer Tests (Mattson et al. (2019)) (also included in this package). References Mattson, E.D., Neupane, G., Plummer, M.A., Hawkins, A., Zhang, Y. and the EGS Collab Team 2019. Preliminary Collab fracture characterization results from flow and tracer testing efforts. In Proceedings 44th Workshop on Geothermal Reservoir Engineering, edited, Stanford University, Stanford, California.

Following the successful stimulation of Desert Peak target EGS well 27-15, a circulation test was initiated by injecting a conservative tracer (1,5-nds) in combination with a reactive tracer (7-amino-1,3-naphthalene disulfonate). The closest production well 74-21 was monitored over the subsequent several months.

Synthesis of a novel thallium-salen fluorescent compound with potential use as a tracer for subsurface fluid flow.

This is an analysis of the pressure falloff in stage 1 fracture stimulation of FORGE well 16A(78)-32. The objective of this research is to understand the information content of the well stimulation data of FORGE Well 16A(78)-32. The Stage 1 step-rate test, a variant of the classic diagnostic fracture injection test (DFIT), contains valuable information about the success of well fracturing and the nature of resulting formation stimulation in the drainage volume of Well 16A(78). The analysis we have provided is based on the classic pressure transient analysis in petroleum reservoirs. The next step in the analysis is to use the information we have discovered in the analysis of tracer flowback data. This set of slides we have provided includes the pressure falloff analysis of the data recorded during stimulation of Stage 1 in injection Well 16A(78)-32 conducted in April of 2022. To honor multiple rate a superposition approach for linear flow regime was applied. The analysis yielded a permeability two orders of magnitude larger than permeability from cores. Our calculated permeability is essentially the effective permeability of micro- and macro-fracture system in the stimulated volume of the Well 16A(78)-32. Another observation is that after using the classic G-function plot, no closure stress was observed. This could suggest that pre-existing natural fractures were reopened during stimulation and yet had no propensity to close in accordance to the poroelastic properties.