Abstract
Mud acid treatments are normally designed by approximating the complex mineralogy of a sandstone using a 'lumping' procedure. Minerals are classified as either fast reacting or slow reacting and the rates of their reaction with hydrofluoric acid are determined by analyzing the acid effluent from acidized core plugs. For most treatments carried out at modest temperatures and at reasonable rates, this approach is satisfactory. In this paper, we show that at higher reaction temperatures, the simple two-mineral dissolution model does not apply because an intermediate product of the HF reaction with quartz, feldspars, and clays (H2SiF6) begins to react further with both clays and feldspars. This new reaction must be included to model the data. The additional reaction, not observed at lower temperatures, has important consequences when it does occur. For example, the acid injection rate is no longer a critical factor. In fact, slow rates in deep formations are preferred. The analysis presented here shows that retarded acids are unnecessary. Contrary to previous concepts, mud acid itself provides a deep penetrating capability. This surprising result may account for the high percentage of successful treatments even when carried out under a wide range of differing conditions.
| Original language | English |
|---|---|
| Title of host publication | Proc Int Symp Form Damage Control |
| Editors | Anon |
| Publisher | Publ by Soc of Petroleum Engineers of AIME |
| Pages | 323-336 |
| Number of pages | 14 |
| Publication status | Published - 1992 |
| Externally published | Yes |
| Event | Proceedings of the International Symposium on Formation Damage Control - Lafayette, LA, USA Duration: 26 Feb 1992 → 27 Feb 1992 |
Other
| Other | Proceedings of the International Symposium on Formation Damage Control |
|---|---|
| City | Lafayette, LA, USA |
| Period | 26/2/92 → 27/2/92 |
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ASJC Scopus subject areas
- Engineering(all)
Cite this
Relationship between reservoir mineralogy and optimum sandstone acid treatment. / Da Motta, Eduardo; Plavnik, Benjamin; Schechter, R. S.; Hill, A. D.
Proc Int Symp Form Damage Control. ed. / Anon. Publ by Soc of Petroleum Engineers of AIME, 1992. p. 323-336.Research output: Chapter in Book/Report/Conference proceeding › Conference contribution
}
TY - GEN
T1 - Relationship between reservoir mineralogy and optimum sandstone acid treatment
AU - Da Motta, Eduardo
AU - Plavnik, Benjamin
AU - Schechter, R. S.
AU - Hill, A. D.
PY - 1992
Y1 - 1992
N2 - Mud acid treatments are normally designed by approximating the complex mineralogy of a sandstone using a 'lumping' procedure. Minerals are classified as either fast reacting or slow reacting and the rates of their reaction with hydrofluoric acid are determined by analyzing the acid effluent from acidized core plugs. For most treatments carried out at modest temperatures and at reasonable rates, this approach is satisfactory. In this paper, we show that at higher reaction temperatures, the simple two-mineral dissolution model does not apply because an intermediate product of the HF reaction with quartz, feldspars, and clays (H2SiF6) begins to react further with both clays and feldspars. This new reaction must be included to model the data. The additional reaction, not observed at lower temperatures, has important consequences when it does occur. For example, the acid injection rate is no longer a critical factor. In fact, slow rates in deep formations are preferred. The analysis presented here shows that retarded acids are unnecessary. Contrary to previous concepts, mud acid itself provides a deep penetrating capability. This surprising result may account for the high percentage of successful treatments even when carried out under a wide range of differing conditions.
AB - Mud acid treatments are normally designed by approximating the complex mineralogy of a sandstone using a 'lumping' procedure. Minerals are classified as either fast reacting or slow reacting and the rates of their reaction with hydrofluoric acid are determined by analyzing the acid effluent from acidized core plugs. For most treatments carried out at modest temperatures and at reasonable rates, this approach is satisfactory. In this paper, we show that at higher reaction temperatures, the simple two-mineral dissolution model does not apply because an intermediate product of the HF reaction with quartz, feldspars, and clays (H2SiF6) begins to react further with both clays and feldspars. This new reaction must be included to model the data. The additional reaction, not observed at lower temperatures, has important consequences when it does occur. For example, the acid injection rate is no longer a critical factor. In fact, slow rates in deep formations are preferred. The analysis presented here shows that retarded acids are unnecessary. Contrary to previous concepts, mud acid itself provides a deep penetrating capability. This surprising result may account for the high percentage of successful treatments even when carried out under a wide range of differing conditions.
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M3 - Conference contribution
SP - 323
EP - 336
BT - Proc Int Symp Form Damage Control
A2 - Anon, null
PB - Publ by Soc of Petroleum Engineers of AIME
ER -