Stratigraphy Fracture in PANG 0003 well, Claromecó Basin, Buenos Aires province, Argentina

Abstract

The PANG 0003 well records the Tunas Formation (Permian) in Claromecó basin area. The aim of this study was to characterize natural fractural in this well. The dominant lithofacies in cores are represented by sandstone and mudrocks facies. Different fractures set, according to their orientation respect vertical well axis, were surveyed:  Vertical fractures (Set I, α: 0°); horizontal fractures (Set II, α: 90°) and conjugate fractures, intersecting the axis of the well at angles of α: ±30° (Set III) and α: ±70° (Set IV).  Set I and II correspond to extension fractures while sets III and IV to shear fractures. Aperture values are less than 2 mm, while the lengths are limited to the dimensions of the samples. Isolated and crosscutting relationships registered systems of interconnected fractures, completely and partially cemented by quartz, carbonate (calcite), pyrite and sulfates. Factors that influence development and distribution of fractures are related to regional tectonics and internal factors, such as lithology, diagenesis processes (compaction and cementation), diagenetic fluids presence, total organic carbon (TOC) content and maturation processes of organic matter, these last exclusively in mudrocks facies.