Determination of Fracture Aperture: A Multi-Tracer Approach
- Key words
- Reservoir Engineering; Reinjection; Tests; Tracers; Models; Fractures; Adsorption; Matrix Diffusion Model
- Location
- Wairakei, New Zealand
- Conference
- Geothermal Resources Council Transactions
- Year
- 1988
- Session
- Tracer testing; Fractures; Injection; Fluid dynamics; Comput
- Language
- English
Abstract
This work shows that fracture aperture can be calculated from tracer tests involving two tracers with different affinities for absorption onto the rock. In 1983 Jensen proved that fissure width can be determined when absorption effects are neglected. Absorption introduces an additional unknown, the retardation factor, into the governing equations. When two tracers are injected, the number of available equations expands to match the number of unknowns. This article also presents equations based on the matrix diffusion model which allow estimation of fracture aperture through visual examination of tracer tests. Tracer data from tests in the Wairakei geothermal field in New Zealand were analyzed by the visual method. The results were compared to computations using nonlinear regression. The two analyses differed randomly with an average variation of +/- 40%.
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