Numerical Studies of the Decrease in Permeability Caused by Deposition of Silica Around an Injection Well
- Key words
- Reservoir Engineering; General; Silica; Injectivity; Models; Pressure Decline; Radial Distance; Permeability; Hatchobaru; Japan; Otake
- Conference
- Geothermal Resources Council Transactions
- Year
- 1986
- Session
- Injection; Silica; Scaling; Computer modeling; Permeability
- Language
- English
Abstract
We present a mathematical model to estimate the injectivity decrease caused by silica deposition around a reinjection well for isothermal injection. It consists of two continuity equations of fluid mass and silica, and the rate equation of silica deposition. The rate equation deals with the rapid decrease in permeability at early stages, and the following slow decrease which were observed both in laboratory experiment and the actual reinjection. In this calculation, the Otake water (90°C and 500 ppm of SiO2) is assumed to have been injected into the porous reservoir with a homogeneous thickness. The results indicate that the area where permeability decreased remarkably is restricted in the close vicinity of the reinjection well.
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