IDENTIFICAÇÃO DE LITOTIPOS NOS PERFIS DE POÇO DO CAMPO DE NAMORADO (BACIA DE CAMPOS, BRASIL) E DO LAGO MARACAIBO (VENEZUELA) APLICANDO ESTATÍSTICA MULTIVARIADA

Abstract

IDENTIFICATION OF LITHOTYPES IN WELL LOGS OF NAMORADO FIELD (CAMPOS BASIN, BRAZIL) AND MARACAIBO LAKE (VENEZUELA) APPLYING MULTIVARIED STATISTICS The identification of lithotypes along a borehole is one of the most important contributions of borehole geophysics to geological studies inside the petroleum industry. However, it is a difficult task, because the measurements performed in the well express the changes of the physical properties and, not necessarily, the lithological variations. This work shows a methodology based on discriminant analysis technique for the identification of lithotypes in well logs, by means of the association between the physical property variations and the lithological types in depth. The geophysical logs applied for the evaluation of this methodology were gamma ray (GR), sonic (DT), neutronic porosity (PHIN), density (RHOB) and resistivity (ILD). In this form, we tested this scheme in two wells of Namorado Field (Campos Basin, Brazil) and another two of Maracaibo Lake (Venezuela). The obtained results are interesting in the sense of the automatic identification of lithotypes using well logs. Thus, the optained results allow to observe an excellent agreement between the well log interpretations or the geological column descriptions of the well and the lithological types identified by the method.