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Microhole Smart Steering and Logging-While-Drilling System
Project Number

The objectives of this project are to design and build 1) a smart drillbit steering motor integrated with a high-performance downhole motor and 2) a logging-while-drilling (LWD) formation resistivity evaluation sensor that provides real-time information about the rock being drilled. The tools will be designed for deployment in ultra-small diameter wellbores.


Baker Hughes INTEQ 
Houston, TX


State-of-the-art BHAs for coiled tubing drilling of (CTD) 3 1/2-inch diameter (microhole) horizontal wells tend to drill holes that are not smooth and straight. The lack of straightness leads to higher friction when sliding the coil, which limits the maximum horizontal extension that can be drilled with coiled tubing equipment.

Also absent in the currently available CTD BHAs for microholes is a suitable LWD tool. In order to keep the well within the target zone and above the oil-water contact, resistivity measurements taken during the drilling process are needed to provide instantaneous information about the distance to the water boundary. This allows the well to be drilled for maximum recovery and minimum risk of water invasion. Furthermore, such formation evaluation sensors will be able to detect trapped hydrocarbons along the well path.

Project Results
Two prototypes were manufactured of each tool, and field tested in an Alaskan North Slope well in April 2006.

2 3/8-inch Rib Steering Motor

  • Assembly of two prototypes completed
  • Lab test and maintenance of one prototype completed successfully
  • Field test in Prudhoe Bay Alaska completed successfully
  • Smooth well bore with minimized doglegs achieved
  • Prototypes shipped back to Celle, Germany plant for inspection

2 3/8-inch Multiple Propagation Resistivity Device

  • Assembly of two prototypes completed
  • Lab test and maintenance of one prototype completed successfully
  • Field test in Prudhoe Bay Alaska completed successfully
  • Excellent resistivity data were gathered and made a logging run redundant
  • Prototypes shipped back to Houston for inspection

BHA Integration

  • The BHA integration test in Anchorage was completed successfully without any major problems
  • Integration of new components into drilling setup completed
  • Both RSM and MPR worked as expected under downhole conditions
  • Detailed field test documentation is ongoing

The advanced drilling, steering, and logging bottomhole assembly (BHA) is expected to enable faster drilling, increased well-path accuracy, improved hole quality, and longer horizontal sections. The improvements in drilling and LWD will lead to increased production while decreasing the number of wells needed.

Lower costs and reduced environmental risks of drilling smaller holes with smaller-footprint rigs and minimal drilling fluid volumes make the technology ideal for producing remaining oil in shallow, mature U.S. reservoirs. Step-out wells, lateral deep perforations, and well deepening all can improve recovery of domestic resources.

Project Summary
The 2 3/8-inch diameter RSM is being designed to serve a 3 1/2-inch or smaller diameter hole. Modules are being designed so they fit seamlessly in the commercially available modular 2 3/8-inch CoilTrak™, a CTD assembly. Hydraulically powered moveable ribs on the steering motor generate steering forces in every direction, allowing both smooth curves and straight borehole sections to be drilled. The MPR tool is being developed for microholes that will allow true real-time geosteering with instantaneous steering actions based on resistivity (and gamma) measurements. See Results section above for a summary of work done.

Current Status

(June 2006)
Both components of the project, the RSM prototype and the MPR prototype, have been successfully field tested. The project received a no cost extension to June 30, 2006 due to the manufacturing of downhole drillstring components being detrimentally affected by the current high level of activity in the oil industry. DOE is awaiting the final report for the project.

Project Start
Project End
DOE Contribution


Performer Contribution

$249,084 (25% of total)

Contact Information

NETL - Sue Mehlhoff ( or 918-699-699-2044)
Baker Hughes INTEQ - John D. Macpherson ( or 713-625-4412)

Rib steering motor for 2 3/8-inch coiled tubing.
Rib steering motor for 2 3/8-inch coiled tubing.