FIELD-TESTING A THROUGH-THE-BIT HIGH-DEFINITION ELECTRICAL B
A new, ultraslim wireline borehole-imager tool for use in oil-based mud provides photorealistic images. The imager is designed to be conveyed through drillpipe. At the desired well section, it exits the drillpipe through a portal drill bit and starts the logging. Field test measurements in several horizontal, unconventional wells in North America show images of fine detail with a large amount of geological information and high value for well development. A relatively new solution for conveying tools to the deepest point (TD) of high-angle or horizontal wells uses a drill bit with a portal hole at the bit face. As soon as the bit reaches the total depth, a string of logging tools is pumped down through the drillpipe. The tools exit the bit through the portal hole, arriving in the open hole and are ready for the uplog. The tools operate on a battery and store the log data in memory so that no cable is interfering as the drillpipe is tripped out of the well while the tools are acquiring data. The quality of wireline electrical borehole images in wells drilled with oil-based mud has significantly improved in recent years. Modern microresistivity imagers operate in the megahertz-frequency range, radiating the electromagnetic signal through the nonconductive mud column. A composite processing scheme produces high-resolution impedivity images. The new ultraslim borehole-imager tool uses these measurement principles and processing methods. Innovating beyond the existing tool designs, the tool is now re-engineered to dimensions sufficiently slim to fit through drillpipes and to use through-the-bit logging techniques. The new ultraslim tool geometry proves highly reliable and, due to the deployment technique, highly effective in challenging hole conditions. The tool did not suffer any damage and showed only minute wear over more than 20 field test wells. The tool’s 12-pad geometry provides 75% coverage in a 6-in. diameter borehole, and its image quality compares very well with existing larger tools. The field test of this borehole-image tool covers all scenarios from vertical to deviated and to long-reach horizontal wells. Geological structures, sedimentary heterogeneities, faults, and fractures are imaged with detail matching benchmark wireline images. The interpretation answers allow operators of unconventional reservoirs to employ intelligent stimulation strategies based on geological reality and effective well development. A new high-frequency borehole imager for wells drilled with oil-based mud is introduced. Deployed through the drillpipe and its portal bit, the imager carries photorealistic microresistivity images into wells where conventional wireline conveyance techniques reach their limits in both practicality and viability.
Standard price: 10.00
Discounted price: 1.00
10.00
You could save: 90.0%
Author(s):
Richard Bloemenkamp, Elia Haddad, Nadege Bize-Forest, Laetitia Comparon, Peter Schlicht
Company(s):
Schlumberger
Year:
2021