Acidizing wells with acetic/HF acid mixtures to minimize cement dissolution

E. P. da Motta, C. R. Miranda, S. M.C. Anjos, J. A. Ribeiro, E. Chaves

Research output: Contribution to conferencePaper

Abstract

Cement attack by acid during matrix acidizing operations has created severe zonal isolation problems in wells with multiple adjacent permeable zones, operated by PETROBRAS. This effect was observed in several wells treated with conventional HCl-HF acid mixtures, even when cement bond logs prior to the acid job were excellent. This paper presents a series of lab experiments showing that acetic acid, alone or mixed with HF, dissolves much less cement than HCl and HCl-HF mixtures with the same carbonate dissolving power. The reaction of acetic acid with cement forms a protective skin that inhibits further acid attack. The organic formulations were tested in an acidizing simulator, before being used in the field. The paper also presents field test results which confirmed that the acetic acid mixtures did not break zonal isolation (cement consumption was restrained to the perforated interval) and were able to generate 6- to 40-fold increases in the injectivity and productivity of the wells.

Original languageEnglish
Pages77-88
Number of pages12
Publication statusPublished - 1 Jan 1996
EventProceedings of the 1996 International Symposium on Formation Damage Control - Lafayette, LA, USA
Duration: 14 Feb 199615 Feb 1996

Other

OtherProceedings of the 1996 International Symposium on Formation Damage Control
CityLafayette, LA, USA
Period14/2/9615/2/96

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ASJC Scopus subject areas

  • Energy Engineering and Power Technology
  • Geotechnical Engineering and Engineering Geology

Cite this

da Motta, E. P., Miranda, C. R., Anjos, S. M. C., Ribeiro, J. A., & Chaves, E. (1996). Acidizing wells with acetic/HF acid mixtures to minimize cement dissolution. 77-88. Paper presented at Proceedings of the 1996 International Symposium on Formation Damage Control, Lafayette, LA, USA, .