INTRINSIC CARBON-OXYGEN LOGGING FOR ENHANCED CONSISTENCY OF
Carbon-oxygen (CO) logging is a valuable measurement for dynamic reservoir saturation monitoring, especially in mixed salinity and freshwater environments. All CO logs currently available are based on apparent measurements. The responses of these raw measurements are not comparable between different tools. Tool-specific calibrations are used to convert apparent CO logs to reservoir saturation: the answer product of CO logging. In this paper, a new concept of intrinsic CO is presented so that raw logs from different tools can be compared for enhanced log quality control and consistent data interpretation. For a given system of rock, oil, and water, intrinsic carbon (C) and intrinsic oxygen (O), thus the CO ratio, are theoretically calculated. For the same system, apparent CO is also obtained using the currently available methodology. A correlation between the theoretical intrinsic CO and apparent CO is established, which is used to convert the apparent CO to intrinsic CO, enabling an intrinsic CO output of the CO logs so that the intrinsic CO logs from different tools are comparable. Both laboratory and Monte Carlo simulation studies are conducted. Systems studied include sandstone and limestone with different porosities. Water and oil saturation were also varied to investigate the effect of fluid saturations. Borehole sizes are 6 and 8 in., and borehole fluids are water and oil. Separate correlations between intrinsic and apparent CO for sandstone and limestone systems are established successfully with very high correlation coefficients. For the first time, this paper details an intrinsic CO log for enhanced log quality control and consistent reservoir saturation monitoring, which ultimately makes the saturation output of CO logs independent of logging tools used in acquiring the raw data.
Standard price: 10.00
Discounted price: 1.00
10.00
You could save: 90.0%
Author(s):
Shouxiang Mark Ma, Nacer Guergueb, Weijun Guo, Mahmoud Eid
Company(s):
Saudi Aramco, Halliburton
Year:
2021