Extracting mud invasion information using borehole radar - A numerical study

Extracting mud invasion information using borehole radar - A numerical study

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

2023

In hydrocarbon drilling, mud filtrate penetrates permeable formations and alters the pore fluid characteristics in the immediate vicinity of the borehole. Typically, the prevailing in situ pore fluids are displaced by the invading mud filtrate, which leads to gradually changing distributions of the fluid and electrical properties. Understanding this invasion process is crucial for the interpretation of logging data and associated reservoir evaluations. Conventional logging methods tend to be inadequate for this purpose as their resolution is too low. We find that invasion depth can be determined from borehole radar data using an optimized antenna configuration and time-lapse measurements. A series of parametric sensitivity analyses provide information about the effects of variations of the rock and fluid properties on the identification and extraction of borehole radar signals reflected from the invasion front. Our results suggest that by embedding the radar antennas in cavities filled with an absorbing dielectric material, it is possible to minimize the interference arising from the metal components of the logging tool. In the simulated reservoir scenario, a time-lapse measurement mode with a time interval of at least 6 h can reliably extract the radar signals reflected from the invasion front, and the proposed borehole radar has a lateral detection range from 0.15 to 1 m. A comprehensive range of parametric sensitivity analyses indicates that the signals reflected from the invasion front are principally influenced by oil viscosity, porosity, and mud and formation water salinity, as well as by molecular diffusion coefficient and cementation exponent. These properties and parameters should be carefully explored and assessed when applying borehole radar to evaluate mud invasion information in a reservoir environment.

borehole geophysics
ground-penetrating radar

http://resolver.tudelft.nl/uuid:0fd002f8-2386-4735-b5e7-a2fae3608152

https://doi.org/10.1190/geo2022-0121.1

2023-09-01

0016-8033

Geophysics, 88 (2), D69-D83

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

© 2023 F. Zhou, Iraklis Giannakis, Antonios Giannopoulos, Klaus Holliger, E.C. Slob