Geochemistry Characterization and Continuity Studies in a Carbonate Cuban Field
Authors: Dominguez Sardinas Zulema , Pascual Olga , Lopez Jose Orlando , Laffita Cristina , Om Tapanes Neyda 
Published: December 2007

A reservoir geochemical study on one oil field located at the northern coast of the Habana-Matanzas land is shown.

The physico - chemical and chromatographic characteristics from 6 oil samples were studied. Continuity studies on the reservoir were carried out. The similarity of the star diagrams of the oils expresses good communication among the wells. Secondary processes like the flushing had been affected the oil quality.

Introduction.

The work develop a study of geochemistry of reservoir in a deposit, of carbonated rocks located on the north coast of the flatness Havana - Matanzas.

In the achievement of the study they were selected to be analyzed, six oils. The samples of the first 5 oils were taken the same day. The sixth sample was taken later.

It is important to clarify that this well has confronted problems, producing with high % of water.

Of the study of the geology of the deposit we can appreciate that there are wells that they produce of more than one cloak which physicist - chemistry can influence in the differentiation of the oils as for his chromatographic characteristic.

Description and Application of Equipment and Processes.

The figure 1 showsthe analytical scheme continued for the achievement of the study. The gravities API decided for the method IP-160, the content of sulfur was determined by the gost 1437, the stickiness decided by means of rotational viscosimeter and the precipitation of the asphalting was realized by ether of 60–80th oil.

The saturated fraction analyzed in a gaseous chromatograph PHILLIPS 4400 with detector FID, capillary column DB-1 of 30m, 0.25mm I gave, 0.25um of thickness of movie, using a program of temperature of 60ºC during a min., 60–140ºC to 40ºc/min and of 140–300ºC to 4ºc/min. The software for chromatography, PC version 5.27, realized the prosecution of the byline.

The crude oil without dividing was analyzed, for the characterization of the fraction C15 - in a gaseous chromatograph CHROMPAC 9001 with detector FID using capillary column DB - Petro. of 50m, 0.2mm of interior diameter and 0.5um of thickness of movie, using a program of temperature.

The data procedure was made wich Master II software, version 2.4, developed by CHROMPACK. Internacional B.V. 1995

Presentation of Data and Result.

In the table the 1 can appreciate that these oils present low values of gravities API (11.6–12.6), high places percents of content of sulfur (6.1 – 6.78), of Asphalting (17.3–23.25) and of resins (22.7 – 24.59); what classifies them as heavy, highly sulphurous oils and resinous. The contents of saturated and aromatic compounds are low, minors of 50 %. The Triangular diagram (fig.2), it shows us the grouping of these oils indicating the resemblances as for the composition of the same ones.

The chromatograms of the saturated fraction (C15) figs.3 and 4 present humps of not decisive compounds, with maximums of n - parafins in the zone C15-C19, which is typical of oils originated in rocks carbonated and in marine ambience. The high place contained of isoparafins is difficult the determination of the relations Pr/Ph, Pr/nC17 and Ph/nC18. In spite of this the determination of these last two relations &gt;1, demonstrates that the process of biodegradation has not been take place