Mechanical stratigraphy and structural control of oil accumulations in fractured carbonates of the Irati Formation, Paraná Basin, Brazil

Autor(es)

Rodrigo Irineu Cerri ^[1] ; George Luiz Luvizotto ^[2] ; Francisco Manoel Wohnrath Tognoli ^[3] ; Lucas Veríssimo Warren ^[4] ; Juliana Okubo ^[5] ; Norberto Morales ^[6]

Afiliação do(s) autor(es)

^[1] Universidade Estadual Paulista “Júlio de Mesquita Filho” - Brasil

^[2] Universidade Estadual Paulista “Júlio de Mesquita Filho” - Brasil

^[3] Universidade do Vale do Rio dos Sinos - Brasil

^[4] Universidade Estadual Paulista “Júlio de Mesquita Filho” - Brasil

^[5] Universidade Estadual Paulista “Júlio de Mesquita Filho” - Brasil

^[6] Universidade Estadual Paulista “Júlio de Mesquita Filho” - Brasil

• Tipo de documento: Artigo Científico
• Fonte: BRAZILIAN JOURNAL OF GEOLOGY; v. 50, n. 3 2020-07-24.

Resumo

Abstract Fracturing analysis of low-permeability rocks as reservoir analogs have increased in recent years. The main mechanism involved in the development of secondary porosity in low-permeability, fine-grained limestones of the Irati Formation is fracturing. In these rocks, oil accumulates along fracture planes, vuggy porosity, microfractures, breccias, as well as bedding discontinuities. Joints represent the central element for oil migration and the connection between accumulation sites. Joints are unevenly distributed across the succession of rock types, where carbonate rocks have a much denser array of joints than shales and siltstones. From a mechanical stratigraphy point of view, limestones have a brittle behavior and constitute mechanical units. Ductile shale and siltstone are mechanical interfaces capable of blocking joint propagation. Joints running NW-SE are more effective in trespassing the mechanical interface and are, therefore, more persistent. Joints running NE-SW are less persistent because the ductile behavior of the first two shale beds above the limestone blocks their propagation. The spatial arrangement of regional NW-SE and NE-SW joints promoted reservoir connection, allowing oil migration and accumulation. The joints and oil migration (at least three phases) developed as a consequence of the Gondwana Breakup and are also associated with local pressure gradients. (AU)

• Processo FAPESP: 13/19878-6 - Análise integrada do padrão de fraturamento em rochas carbonáticas da formação Irati utilizando laser scanner terrestre
• Beneficiário: Rodrigo Irineu Cerri
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica