GNGTS 2021 - Atti del 39° Convegno Nazionale

GNGTS 2021 S essione 3.1 406 QUANTITATIVE FLUID FLOW MODELLING OF AN ACTIVE CARBONATE- BEARING PETROLEUM SYSTEM CONSTRAINED BY SUBSURFACE, OUTCROP AND LABORATORY DATA R. Ruggieri 1 , F. Trippetta 1 , L. Petracchini 2 1 Sapienza University of Rome, Department of Earth Sciences, Rome, Italy 2 Consiglio Nazionale delle Ricerche, Istituto di Geologia Ambientale e Geoingegneria, Rome, Italy Keywords: Carbonate reservoir, 3D structural modelling, dynamic modelling, oil migration. Fluid flow simulation in Petroleum System Modelling is a key tool to evaluate the exploration risks since it actually defines the possibilities of hydrocarbon generation and accumulation. However, building such models requires a large amount of knowledge in terms of both geological history and rock properties of the investigated area, making this modelling quite rare in literature in particular for carbonate petroleum systems. In this work, we focus on the Burano-Bolognano petroleum system located in the Abruzzo region, (central Italy) and it extends from the norther sector of the Majella Mountain to the Cigno/Vallecupa/Bonanno oil fields (located about 10 km north of the Majella massif). This area has been extensively investigated in the past century by exploration activities. Firstly, we present a 3D structural model and then a 2D fluid flow model, developed starting from the dense well dataset acquired over the years that was recently digitalized and updated with laboratory data. The geological model has been reconstructed correlating all available well data with field scale geological interpretations and laboratory analysis. The geological model points out that the main stratigraphic intervals are homogeneous in thickness and laterally continuous over the investigated area, defining a typical geometry of a low-angle carbonate ramp. From the 3D structural model, we extracted a 2D geological section that crossed through the deepest wells and subsequently we imported this section into the PetroMod software to understand how the Burano-Bolognano petroleum system has worked over geological time. Preliminary dynamic results highlight that the underlying Triassic Burano source rock is enough mature to generate oil. The best fit between the final distribution, obtained from the model, and the actual distribution of the known hydrocarbon accumulations in study area is obtained by placing the source rock at north of the Majella massif. Moreover, migration pathways evidence that the vertical movement has an important role in the first phase of oil migration, moving oil from the source rock into the reservoir rocks. Then, the system is laterally drained for tens of kilometers with a gradual oil biodegradation. This is very well confirmed by API gravity data, reported in deep wells (i.e, Bonanno 1 and Cigno 2), and in very good agreement with laterally drained models (Demaison and Huizinga, 1994). The presented results are of a high relevance in general for carbonate-ramp reservoir studies that are usually very challenging to be correctly modeled due to their high heterogeneities related to fabric, texture, fractures. References ALBA (August 1942) - Campagna geologica ALBA – Scala 1:25.000, versante Nord-Ovest della Maiella Quadro indice (10th of August 1942). ENI S.p.A. Historical Archives, Roma. (doc. n. 48449). ALBA (July 1943) - Relazione sulla Campagna dei Sondaggi e Cubaggio accertato e probabile del giacimento asfaltico-bituminoso del versante settentrionale della Maiella. In Campagna Geologica ALBA. ENI S.p.A. Historical Archives, Roma. (doc. n. 48449).