High-quality images from an LWD ultrasonic imaging tool are used to identify natural and induced fractures and optimize hydraulic fracturing practices in wells drilled with oil-based mud.
A newly designed LWD ultrasonic imager was developed due to the high demand for acquiring high-quality wellbore images in oil-based mud environments where traditional resistivity tools usually do not provide the desired detailed. Characterization of natural and induced fractures, and wellbore geometry are used to identify and characterize formation characteristics just hours after the well reaches TD. This enables the timely detection of fracture dominated zones enabling optimization of the ongoing hydraulic fracturing operations.
The ultrasonic imager provides 360-degree measurements of travel time and amplitude around the wellbore, taking advantage of the rotation of the drill string; the travel time measurements are used to provide a high-resolution caliper and the amplitude is used to detect formation features such as bedding planes, fractures and borehole breakouts.
The image acquisition while drilling in high rate-of-penetration (ROP) and high revolutions per minute (RPM) scenarios allows the downhole logging sensor to acquire azimuthal data in a cost-efficient scenario which does not require additional rig downtime after the well is drilled. The characterization of the natural fracture network and induced fractures helps to better assess their potential interaction with hydraulic fractures and thus allowing the implementation of hydraulic fracturing practices that allow porosity and permeability enhancement in virgin areas of the field.
The application of unique LWD technology which allow for timely reservoir characterization to further enhance completions optimization provides reservoir productivity enhancement without affecting drilling operations in unconventional shale reservoirs.