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Current Industry Capability Summaries for Two Topics Related to Small-Diameter Wells: Hydraulic Motion in Small-Diameter Pipes, and Small-Diameter Drilling Motors Available to Industry*
Project Number

The original goal of the project was to provide DOE with summary reports on the current capabilities of the petroleum service industry related to downhole drilling and production. The objective of the newly defined scope of work is to 1) investigate the history and state of the art and capabilities of downhole motors for both small-diameter holes less than 3 1/2-inches and 2) to identify the total work related to hydraulics in small-diameter holes, both vertical and horizontal.

This project was directed in support of NETL's Microhole Initiative program planning effort through a sole-source contract.


Rio Technical Services Inc. (Rio) 
Fort Worth, TX


DOE is launching a major research and development initiative to create a small, fast, inexpensive, and environmentally friendly rig for drilling 5,000 foot boreholes to investigate and produce potential oil and gas reserves. The National Energy Technology Laboratory (NETL) in conjunction with Los Alamos National Laboratory (LANL) has developed an operational microdrill that has been successfully demonstrated at depths of less than 700 feet. Rio's project was designed to identify and fill in some of the gaps in knowledge and limitations of microhole drilling and completion.

Project Results
Two reports were provided to DOE:

  • One summarized the history and state-of-the-art and capabilities of downhole motors for small-diameter holes less than 3 1/2-inches.
  • The second identified the total work related to hydraulics in small-diameter holes, both vertical and horizontal.

DOE may use the summary information and recommendations in future program planning.

Project Summary
Rio conducted a literature search and interviewed key knowledgeable persons about the current capabilities of downhole motors related to small diameter drilling and related also to ultra-high-speed drilling bits (rotating up to 50,000 rpm). This effort summarized and defined the operating conditions of the various types of downhole motors and their limitations. The report identified current (at the time) research that was being conducted on the topic by service companies, universities, national laboratories or other research and development organizations. The report identified continuing industry needs in this area of technology.

Rio conducted a review of the available information on the topic of hydraulics of fluid movement through small-diameter pipes or wellbores in both vertical and horizontal orientations. The project was not limited to the oil and gas industry but analyzed other industries where fluid-flow information is essential for operation (i.e., water companies, manufacturing, mining, etc.). A summary of the current understanding of the critical factors, available simulations, and general level of understanding was prepared. The report identified key researchers on this technology and current (at the time) projects being conducted that would be applicable to the microhole technology initiative.

Current Status

(August 2005)
Two reports were completed in 2003-04, and the results were used in DOE project planning.

DOE publications:
Current Capabilities of Hydraulic Motor, Air/Nitrogen Motors, and Electric Downhole Motors, January 30, 2004.
Hydraulic Motion & Fluid Movement Through Small Diameter Pipes and Wellbores, December 12, 2003.

Project Start
Project End
DOE Contribution


Performer Contribution


Contact Information

NETL - Rhonda Jacobs ( or 918-699-2037)
Rio Technical Services Inc. - Lindy Walker ( or 817-735-8264)