Thermodynamic and kinetic aspects of argillaceous sandstone acidizing
The thermodynamic aspect of sandstone acidizing by hydrofluoric acid is examined. It is shown that silica dissolution, with a first order in HF concentration leads nearly exclusively to the formation of fluosilicic acid. Clay and feldspar dissolution is much more complex, and after a uniform alteration of the crystalline lattice, partial precipitation of solicic species occurs when the acid is spent. An approach to the kinetic aspect is made by defining, for a naturally complex medium, not a single reaction rate constant, but a reactivity profile that is a characteristic of the medium. Experimental data obtained enable a correlation to be determined between permeability, porosity, and reactivity. In addition, a qualitative interpretation of acid response curves is given. The numerical simulation of the acidizing process reproduces the experimental results in a satisfactory way. When extended to radial flow, the model brings out the influence of stimulation parameters, injection rate, concentration, and time. (12 refs.)
- Research Organization:
- Inst Francais du Petrole
- OSTI ID:
- 6641817
- Report Number(s):
- CONF-7410175-
- Journal Information:
- Soc. Pet. Eng. AIME, Pap.; (United States), Vol. SPE-5156; Conference: 49. meeting and exhibition of the Society of Petroleum Engineers of AIME, Houston, TX, USA, 6 Oct 1974
- Country of Publication:
- United States
- Language:
- English
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