Presenter
Carlos Sarquez from Halliburton
Co-authors
AKer BP
Abstract
n a well drilled in a Norwegian oil field, characterized by turbidite formations with a variable structural profile including folding and sub seismic faulting, Ultra Deep Azimuthal Resistivity (UDAR) and Deep Azimuthal Resistivity (DAR) inversions were performed to map the complex reservoir. The focus of the UDAR inversions was to resolve the main boundaries away from the wellbore trajectory, while the DAR inversion scope was to resolve more detailed features near the wellbore and qualify a newly developed tool.
To validate the DAR inversion, synthetic inversion models were performed using the resistivity input from offset logs and the pilot hole for the current horizontal well, where the resistivity transitions were linked to layering. Once the recorded data was retrieved the DAR inversions were performed post well, using multiple frequency settings to optimise the results and ensure consistency. In addition to comparing the results against the UDAR inversions, standard resistivity logs were correlated against the results and dips picked from the density images were projected over the inversion to compare results to confirm the structural representation evident on the DAR inversion results.
DAR inversions using recorded data resolved a resistivity distribution revealing the sub-seismic layering and structures controlling the fluid and lithology distribution as expected. The resistivity distribution evident in the UDAR inversion showed the bigger scale lithology and fluid boundaries with a similar morphology out to a greater depth of investigation, but the DAR inversion gave more detailed results due to its shorter spacing and the higher frequencies available. Integrating the density image interpretation with the DAR results enriched the DAR results defining the same overall structures but in even greater detail. Comparison of the target well data to the pre-drill phase synthetic models was performed, these results were comparable adding confidence to the planning phase for future wells.
The usage of DAR inversions in thin layered reservoirs reduces the uncertainty of the main resistivity distributions. These inversion results have a decreased depth of investigation when compared to UDAR inversions but provide much more detail allowing improved integration with shallow LWD log data.
Biography
Carlos Sarquez is the Geosteering Lead at Halliburton for AkerBP operations. Sarquez began working with Halliburton in 2003 as a geosteering geologist in Colombia, followed by working as geosteerer based in Canada 2010, in 2015 started to cover geosteering operations in Venezuela. Sarquez moved to Norway to work as geosteering geologist in 2018. In 2023 assumed his present role. Holding a Bsc degree in geology from the Industrial University of Santander, Colombia.