Ricardo Martínez-Ibarra¹, Esteban Cedillo-Pardo¹, Jose Manuel Grajales-Nishimura²
(1) Instituto Mexicano del Petróleo, México, D.F, Mexico
(2) Instituto Mexicano del Petróleo

Abstract: Early Hydrocarbon Migration in the Cantarell Field, Southeastern Mexico: Constrains from Fluid Inclusions

Early stages of hydrocarbon migration were recognized by microthermometric and fluorescence studies in fluid inclusions contained in dolomites of the Cantarell Field, southeastern Mexico. The dolomite occurres as replacement and void filling, and it contains both hydrocarbon and aqueous primary fluid inclusions. This indicates that the early arrival of hydrocarbons into the reservoir was synchronic with the dolomitization. Microthermometric studies show that dolomitization occurred at 80-110ºC with salinities of 2-8 Wt% NaCl, supporting an origin in burial settings for dolomites.

From several dolomite generations only two of these were observed to be associated to oil migration. In the first generation, fluorescence studies show heavy hydrocarbon fluid inclusions, with red fluorescence. These were trapped close to the cores of the crystals; yellow and blue inclusions were trapped toward the edge indicating that lighter oil arrived later. All these are interpreted as early stages of migration into the reservoir. The hydrocarbon fluid inclusions in the second generation of dolomite are yellow and they are related to the begining of the main accumulation of hydrocarbons in the reservoir.

The high density of red fluid inclusions in the western part of the field, and the distribution of yellow and blue fluid inclusions toward the East, seems to indicate that filling of the reservoir started from the West.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana