已发表: 01/07/2022
已发表: 01/07/2022
A new area in the Midcontinent region contains natural fractures that influence hydraulic fracturing performance. An operator wanted to characterize the occurrence and distribution of these natural fractures along the wellbore into the formation for a 3D understanding of the natural fracture trends to optimize well completion design.
To achieve a complete map of fractures at and around the wellbore, Schlumberger recommended a two-pronged approach: acquire standard through-the-bit logging data in oil-based mud to obtain microresistivity images and acquire 3D far-field sonic data using slim dipole logging conveyance for high-quality sonic imaging.
The 3D far-field sonic service workflow automates time picking and event analysis compared with time-intensive, conventional manual determination of reflector dip and azimuth. The service rapidly derives the dip and azimuth of the identified reflectors from the automated event analysis. These events can then be easily integrated with borehole image interpretation constraining the high resolution of near-wellbore reflectors, making them ready to import into 3D geological modeling.
The automated 3D far-field sonic processing combined with the migrated sonic image showed natural fractures extending into the formation beyond 20 ft, providing a missing scale of observation between seismic and borehole imaging. Furthermore, fractures could be detected at distance without intersecting the wellbore, and the fracture orientation could be measured.
A notable change in natural fracture distribution near and far into the formation was observed near the well toe. This data enabled the operator to plan hydraulic fracturing in the interval to generate more fracture complexity and near-wellbore friction during the pumping stage.
—Supervisor of petrophysics and staff geophysicist
A 3D far-field sonic service deployed using slim dipole logging conveyance automates time picking and event analysis to quickly derive true dip and azimuth of fractures beyond 20 ft into the reservoir.
