Caracterización estática de la Formación Lajas a partir de la integración de datos de roca, perfiles eléctricos de pozo y datos de producción, en el yacimiento Barrosa Norte, cuenca Neuquina

Abstract

In this study, the results obtained from the static characterization of the Lajas Formation in the Barrosa Norte deposit (Neuquén basin), which constitutes an unconventional reservoir, specifically a Tight gas Sandstone reservoir. Tight gas or Tight gas Sandstone is the term used the gas trapped in compact sandstone formations. These sediments have petrophysical characteristics (e.g. permeability with values between 0.001 and 0.01 mD, effective poor on the order of 2 to 12%) that lead to consider the deposits of the lower section as tight, and the deposits of the middle and upper section as reservoirs of low permeability. The elaboration of the static model was based on information from well logs, cores, production information and analogous models. The generated model contributes to a better understanding of spatial distribution, the thickness of potential reservoirs, and its petrophysical properties of the medium, in order to more accurately establish the location of a production well. Nineteen wells of this reservoir were stratigraphically correlated, recognizing four zones within the Lajas Formation based on their lithological and petrophysical characteristics. The zones were informally referred and based on its location as Lajas Tope, Lajas Intrasuperior, Lajas Medio and Lajas Inferior. The greatest useful thicknesses (Net Pay) occur in the Upper and Lower sections, and as it can be observed in the electrical records, there are less intercalation of clay facies with respect to the middle sections, on the other hand the Lower section, due to its structural position and greater depth, presents more than 50% of average water saturation and very low porosity and permeability conditions that could result in low productivity conditions. In the Intrasuperior and Media sections, the higher content of heterolitic levels conditions the deterioration of petrophysical properties and the decrease in useful thicknesses. With the static model generated, the reserves were estimated, in the area that includes the location of the well, in this way an additional data is provided that allows evaluate the viability of the proposed well.