Estimating reservoir permeability with borehole radar

Estimating reservoir permeability with borehole radar

Zhou, F. (TU Delft Applied Geophysics and Petrophysics; China University of Geosciences, Wuhan)
Giannakis, Iraklis (University of West London)
Giannopoulos, Antonios (The University of Edinburgh)
Holliger, Klaus (University of Lausanne)
Slob, E.C. (TU Delft Applied Geophysics and Petrophysics)

2020

In oil drilling, mud filtrate penetrates into porous formations and alters the compositions and properties of the pore fluids. This disturbs the logging signals and brings errors to reservoir evaluation. Drilling and logging engineers therefore deem mud invasion as undesired and attempt to eliminate its adverse effects. However, the mud-contaminated formation carries valuable information, notably with regard to its hydraulic properties. Typically, the invasion depth critically depends on the formation porosity and permeability. Therefore, if adequately characterized, mud invasion effects could be used for reservoir evaluation. To pursue this objective, we have applied borehole radar to measure mud invasion depth considering its high radial spatial resolution compared with conventional logging tools, which then allows us to estimate the reservoir permeability based on the acquired invasion depth. We investigate the feasibility of this strategy numerically through coupled electromagnetic and fluid modeling in an oil-bearing layer drilled using freshwater-based mud. Time-lapse logging is simulated to extract the signals reflected from the invasion front, and a dual-offset downhole antenna mode enables time-to-depth conversion to determine the invasion depth. Based on drilling, coring, and logging data, a quantitative interpretation chart is established, mapping the porosity, permeability, and initial water saturation into the invasion depth. The estimated permeability is in a good agreement with the actual formation permeability. Our results therefore suggest that borehole radar has significant potential to estimate permeability through mud invasion effects.

http://resolver.tudelft.nl/uuid:aa383b7f-60a8-421f-8d30-6670e0559ca1

https://doi.org/10.1190/geo2019-0696.1

2020-12-10

0016-8033

Geophysics, 85 (4), H51–H60

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2020 F. Zhou, Iraklis Giannakis, Antonios Giannopoulos, Klaus Holliger, E.C. Slob