Integrated Petrophysical Evaluation Using Organic Shale Petrophysics OSP Approch Based on NMR, Elemental Specrtoscopy, Electrical Borehole Image and Core Data Analysis, of the Unconventional Reservoirs in Kra Al Maru Field, West Kuwait

Abstract

Najmah-Sargelu formations are unconventional reservoirs in West Kuwait in deep section of Kra Al Maru field. Various options were introduced to perform a petrophysical characterization of these unconventional reservoirs. Since a robust petrophysical model is critical for accurate reservoir characterization, a key objective of the current study was to obtain reliable well logging data that could support reservoir modeling and early wellsite decisions. Consequently, the logging program included conventional open hole logs, nuclear magnetic resonance (NMR), and elemental spectroscopy. The scope of the work is to assimilate data from the log sand generate a single integrated petrophysical model of the reservoir.

The organic shale petrophysics (OSP) was applied to provide petrophysical evaluation based on triple-combo data that has been integrated with advanced logs and core data analysis. The porosity partioning was obtained from NMR data. A detailed mineralogy and organic content were obtained from the geochemical spectroscopy logging. The most relevant results of the petrophysical analysis in this work was to improve fluid saturation analysis using OSP. Kerogen identified with the OSP analysis and the NMR under call porosity were in good agreement. The occurrence of kerogen was supported by the presence of redox sensitive elements, such as uranium, nickel, and molybdenum from core XRF data anlysis.

Borehole Image used to identify and characterize types and density of fractures, which contribute to enhance porosity and permeability of these tight reservoirs. A geochemical tool has been designed and developed for the precise determination of formation mineralogy, and lithology, as well as the identification of total organic carbon (TOC).

This work proves that the OSP analysis integrated with Core analysis, NMR data is a key in the petrophysical evaluation of unconventional reservoirs including the water saturation. These results, along with geochemical elemental spectroscopy and Electrical Borehole Image analysis, can be used to obtain a more precise petrophysical evaluation.