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Journal of Porous Media
IF: 1.49 5-Year IF: 1.159 SJR: 0.43 SNIP: 0.671 CiteScore™: 1.58

ISSN Print: 1091-028X
ISSN Online: 1934-0508

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Journal of Porous Media

DOI: 10.1615/JPorMedia.v20.i11.70
pages 1031-1041

STUDY OF DOLOMITE SURFACE STABILITY BY DFT APPROACH CONSIDERING DEFECTS

Raiza Hernandez-Bravo
Instituto Mexicano del Petróleo, Eje Central Lázaro Cárdenas, Mexico City, Mexico

ABSTRACT

The stability of dolomite surfaces has been studied in the present work through a nonparameterized density functional theory (DFT) with the aim to build a molecular model of a rock surface in contact with oil in a carbonate reservoir. The rock surface was studied in its pristine form by considering defects such as cationic substitution and anionic vacancies. Therefore a systematic molecular study was performed by the substitution of Ca+2 by Mg+2 and their influence in the generation of vacancies at the CO2-3 and cationic sites. The molecular simulations showed that Mg+2 presented the highest probability for spontaneous creation of vacancies; that is, the reactions where the substitution of Ca by Mg took place are favored. Therefore the stability is higher when Ca is substituted by Mg. Surface energy results showed that the most stable pristine surface is the one corresponding to the [104] plane of the conventional dolomite cell. The developed model can be used to favor the dolomitization to improve the reservoir quality by the generation of vacancies and stability by the substitution of Ca by Mg incrementing the reservoir porosity in the order of 13%.