HIGH-RESOLUTION MINERALOGY MODELING- A CASE STUDY IN THE VACA MUERTA FORMATION, NEUQUEN BASIN, ARGENTINA

摘要

Accurate mineralogy modeling and interpretation for thinly bedded formations often requires high-resolution data, usually measured in the laboratory from core samples. However, core measurements are expensive and available only from a limited number of wells in a field. On the other hand, high-resolution logging tools are not sufficient to provide a comprehensive mineralogy characterization. Because other types of logging data are also available from many wells, a high-resolution mineralogy analysis combining low-resolution and high-resolution logging data becomes very attractive. This study focuses on solving for high-resolution on mineralogical compositions of the formation combining pulsed-neutron spectroscopy measurements, image logs, and other conventional log responses. A workflow has been developed with the following major steps: 1.Extract lithology volumetric models from high-resolution image logs combined with otherconventional logs; 2.Allocate the modeled mineralogicalcompositions from lower-resolution geochemical logs into mineral compositions for various lithology types; 3.Obtain a high-resolution mineral model; 4.Perform a quality check by comparing thecomputed results with core measurements. To demonstrate the method’s feasibility and applicability, the proposed workflow was used on a Vaca Muerta log example from the Loma Campana field, which has dramatic variations in mineralogy composition. The processing showed very promising results with the computed high-resolution mineral model matching the core data. This result indicates the proposed method could reproduce the mineral composition with a full vertical variability in a thin-bedded formation that would only be available with extensive core measurements. The approach presented here can offer an integrated, high-resolution formation evaluation for key petrophysical properties, such as formation composition, permeability, porosity, and geomechanical properties. The method provides a great advantage over conventional log interpretation by revealing the full vertical variability of a formation that would otherwise appear insensitive for thin layers with limited resolution and compromised accuracy. The promising results generated from this study demonstrate the feasibility of an integrated core-level petrophysical analysis in a cost-effective and timely manner compared to conventional core measurements.