Injection through fractures

Technical Report · Fri May 01 04:00:00 EDT 1987

DOI:https://doi.org/10.2172/7228925· OSTI ID:7228925

Johns, R A

Tracer tests are conducted in geothermal reservoirs as an aid in forecasting thermal breakthrough of reinjection water. To interpret tracer tests, mathematical models have been developed based on the various transport mechanisms in these highly fractured reservoirs. These tracer flow models have been applied to interpret field tests. The resulting matches between the model and field data were excellent and the model parameters were used to estimate reservoir properties. However, model fitting is an indirect process and the model's ability to estimate reservoir properties cannot be judged solely on the quality of the match between field data and model predictions. The model's accuracy in determining reservoir characteristics must be independently verified in a closely controlled environment. In this study, the closely controlled laboratory environment was chosen to test the validity and accuracy of tracer flow models developed specifically for flow in fractured rocks. The laboratory tracer tests were performed by flowing potassium iodide (KI) through artificially fractured core samples. The tracer test results were then analyzed with several models to determine which best fit the measured data. A Matrix Diffusion model was found to provide the best match of the tracer experiments. The core properties, as estimated by the Matrix Diffusion model parameters generated from the indirect matching process, were then determined. These calculated core parameters were compared to the measured core properties and were found to be in agreement. This verifies the use of the Matrix Diffusion flow model in estimating fracture widths from tracer tests.

• Research Organization: Stanford Univ., CA (USA). Stanford Geothermal Program
• DOE Contract Number: AS07-84ID12529
• OSTI ID: 7228925
• Report Number(s): SGP-TR-110; ON: DE88012262
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150904* -- Geothermal Engineering-- Geothermal Reservoir & Well Performance
FLUID FLOW
FLUID INJECTION
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOTHERMAL SYSTEMS
Geothermal Legacy
ISOTOPE APPLICATIONS
MATHEMATICAL MODELS
RESERVOIR ROCK
TRACER TECHNIQUES