3D Mechanical stratigraphy in carbonates of Jandaíra Fm. using UAV and GPR
Analogues of Carbonate Reservoirs; Fm. Jandaíra; Mechanical and Fracture Stratigraphy.
Deciphering and reconstructing the characteristics and evolution of the formation associated to carbonate reservoirs has guided the nowadays research focus. In this study, the high-resolution multidisciplinary investigation conducted on analog outcrops, aims to fill the gap of knowledge which exist in the current field study at a regional scale. The study area is located in Felipe Guerra/RN (Potiguar Basin), where carbonate rocks of the Jandaíra Fm crops out. These rocks are characterized by large carbonate pavements strongly affected by fracturing and dissolution process. The main goal of this study was to analyze the structural, stratigraphic/lithological characteristics of the carbonate rocks exposed in the Fraturas Rasas (AFR) outcrop. The main goal aims on establish the relationships between the structural discontinuities, the primary rock composition and the karstification process. In order to shed light on the mechanical/fracture stratigraphy characteristics several techniques were applied: (a) High-resolution Drone imaging, (b) field quantitative structural analysis; (c) subsurface data (well log and GPR data). Two main fracture sets respectively striking NNW-SSE and ENE-WSW were identified. The NNW-SSE set shows metrical persistent fractures affected byintense dissolution process. Differently, the set ENE-WSW striking fracture set is mainly compartmentalized between the aforementioned fractures set. Moreover, it is less persistent and display minor dissolution evidences. The conducted topological analysis defined a well-connected structural network made up by the documented fracture sets. Statistical analysis suggests that the NNW-WSW striking set is characterized by evenly spacing distribution, while the set ENE-WSW striking set highlights the presence of some fracture clusters. About the subsurface data, the stratigraphy and structural analysis realized with the GPR lines and well
data, allow us to identify of a different degree of deformation, highlighted by the major density of fractures in the deeper and less thick beds, while the topmost thicker beds, shows a less density of structures characterized by higher spacing values. This relation result is directly linked to the variation of the mechanical units (beds) that control the deformation distribution.