Evolución diagenética de la Formación Tunas para el pozo PANG 0001, Cuenca de Claromecó, provincia de Buenos Aires, Argentina: su potencial como reservorio de hidrocarburos

FEBBO B.; NATALIA FORTUNATTI; CESARETTI, N.N.; ARZADÚN, G; TOMEZZOLI, R.N.

Mendoza

Congreso; X Congreso de Exploración y Desarrollo de Hidrocarburos. Simposio de Recursos No Convencionales: Hacia una Nueva Convención; 2018

Asociación Argentina del Petróleo

Diagenetic evolution of Tunas Formation in PANG 0001well, Claromecó Basin, Buenos Aires province,Argentina: its potential as a hydrocarbon reservoir.Claromecó Basin (Carboniferous-Permian) is considered a frontier basin due to its limited geologic knowledge. This basin has economic potential based on coal beds and seams and associated methane gas, recorded underground.The aim of this work is to evaluate the economic potential of Tunas Formation in the PANG 0001 well, based on petrographic, diagenetic and fluid inclusion studies in sandy facies. In addition,oleogenetic potential of muddy faces through TOC (total organic carbon) analysis is determined.PANG 0001 well is located in the basin center. In this well Tunas Formation is made of medium to finesized sandstones, tuffs, mudrocks, carbonaceous mudrocks and coal levels. Identified diageneticprocesses include mechanical compaction, cement precipitation, alteration, replacement, dissolutionand late tectonic fracturing. Physical compaction is the predominant factor, along with precipitation ofdiagenetic minerals reduce porosity and decrease reservoir quality. Secondary porosity is comprised byrock and grain fracture and feldspar and carbonate cement dissolution; its value reaches 0.2 to 0.6%.Fluid inclusions are aqueous, placed mainly in cements, and also organic, with yellow and lightblue fluorescence, located in microfractures and veins; those colors indicate presence of liquid to wetgas hydrocarbons and dry gas (methane) respectively.During early diagenesis precipitation of carbonate cements and mechanical compaction of sandyfacies were dominant. Poral space was reduced by these diagenetic processes. Mesogenesisconditions are proper to generate hydrocarbons and an acid environment to dissolve feldspars andcarbonate cement. Subsequent compaction, tectonic events and fluid pressure generate secondaryporosity, increase the reservoir quality and allow hydrocarbon migration. Finally, quartz and feldsparsovergrowth, late calcite cement precipitation and fractures healing occur during late mesogenesisand reduce porosity.Total organic carbon values are 0.5-5% in mudrocks and 12-26% for carbonaceous mudrocks.Based on previous results, it can be concluded that Tunas Formation has potential as source rockin muddy levels and as reservoir in sandy levels, so the formation can be considered as a potentialspeculative petroleum system: Tunas-Tunas (?).