Petrophysical aspects for a constrained and joint inversion of deep reading LWD-data
Research output: Thesis › Master's Thesis
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2016.
Research output: Thesis › Master's Thesis
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TY - THES
T1 - Petrophysical aspects for a constrained and joint inversion of deep reading LWD-data
AU - Tucovic, Nebojsa
N1 - embargoed until 19-01-2021
PY - 2016
Y1 - 2016
N2 - Rock physics templates are commonly created in the industry to characterize reservoirs based on acoustic impedance and velocity relationships on different measurement scales (laboratory – well logging - seismic). Plotting acoustic impedance versus compressional-shear velocity ratios provide basin-dependent information on porosity, lithology and fluid saturation. To precisely land and navigate wells, extra-deep reading-while-drilling resistivity tools were developed. To integrate these measurements with acoustic and seismic measurements for even better navigation, a thorough understanding of tool responses at lithology boundaries and fluid contacts is required. This study expanded the idea of rock physics templates by including resistivity as an additional parameter. Logging-while-drilling data from 33 vertical or slightly deviated wells from the Norwegian Continental Shelf were used to investigate and evaluate resistivity and acoustic impedance contrast at more than 50 caprock-reservoir boundaries and various fluid contacts in a wide range of lithologies (in various stratigraphic levels, from Permian to Paleogene). The outcome is a new kind of ratio-based rock physics template. The influence of factors such as shale content, porosity, water saturation, and rock anisotropy is taken into account for the analysis of the resistivity and acoustic impedance data sets and to generate rock physics templates. Boundaries between caprock and reservoir can be defined through resistivity and acoustic impedance contrast. Fluid contacts in the reservoir can be detected by either resistivity ratios or acoustic impedance ratios or both depending on type of fluid. Compaction, fluid pressure, temperature, and fluid type play an important role for interpreting the data and templates. Thus, understanding of local and regional geological history, e.g. burial history has to be taken into account. Considering these, the created templates provide a useful tool for estimating lithology boundary and fluid contact conditions for better evaluating deep reading while drilling resistivity tools.
AB - Rock physics templates are commonly created in the industry to characterize reservoirs based on acoustic impedance and velocity relationships on different measurement scales (laboratory – well logging - seismic). Plotting acoustic impedance versus compressional-shear velocity ratios provide basin-dependent information on porosity, lithology and fluid saturation. To precisely land and navigate wells, extra-deep reading-while-drilling resistivity tools were developed. To integrate these measurements with acoustic and seismic measurements for even better navigation, a thorough understanding of tool responses at lithology boundaries and fluid contacts is required. This study expanded the idea of rock physics templates by including resistivity as an additional parameter. Logging-while-drilling data from 33 vertical or slightly deviated wells from the Norwegian Continental Shelf were used to investigate and evaluate resistivity and acoustic impedance contrast at more than 50 caprock-reservoir boundaries and various fluid contacts in a wide range of lithologies (in various stratigraphic levels, from Permian to Paleogene). The outcome is a new kind of ratio-based rock physics template. The influence of factors such as shale content, porosity, water saturation, and rock anisotropy is taken into account for the analysis of the resistivity and acoustic impedance data sets and to generate rock physics templates. Boundaries between caprock and reservoir can be defined through resistivity and acoustic impedance contrast. Fluid contacts in the reservoir can be detected by either resistivity ratios or acoustic impedance ratios or both depending on type of fluid. Compaction, fluid pressure, temperature, and fluid type play an important role for interpreting the data and templates. Thus, understanding of local and regional geological history, e.g. burial history has to be taken into account. Considering these, the created templates provide a useful tool for estimating lithology boundary and fluid contact conditions for better evaluating deep reading while drilling resistivity tools.
KW - Petrophysics
KW - LWD
KW - Logging while drilling
KW - Inversion
KW - Norwegian Continental Shelf
KW - Geology
KW - Resistivity
KW - Acoustic Impedance
KW - Boundary contrasts
KW - Reservoir
KW - Caprock
KW - Fluid contacts
KW - Rock physics templates
KW - Compaction plots
KW - Shale
KW - Smectite
KW - water saturation
KW - Archie
KW - Rock physics
KW - Petrophysics
KW - LWD
KW - Logging while drilling
KW - Inversion
KW - Norwegian Continental Shelf
KW - Geology
KW - Resistivity
KW - Acoustic Impedance
KW - Boundary contrasts
KW - Reservoir
KW - Caprock
KW - Fluid contacts
KW - Rock physics templates
KW - Compaction plots
KW - Shale
KW - Smectite
KW - water saturation
KW - Archie
KW - Rock physics
M3 - Master's Thesis
ER -