Exploration and Production Technologies

Microhole Wireless Steering- While-Drilling System

DE-FC26-05NT15488

Goal
The project goal is to provide a smart steering tool for a modular and economic coiled tubing drilling (CTD) system that allows domestic operators to produce more oil from existing reservoirs. This will be achieved by providing accurate and precise real-time geosteering even under conditions where the rig surface gear and equipment need to be minimized for cost-effectiveness. The following objectives support this goal:

  • Develop a 2 3/8-inch diameter bi-directional power and communications module (BCPM) as a part of the modular CTD bottomhole assembly (BHA).
  • Develop a fit-for-purpose surface control system that communicates with the BHA.

Performer
Baker Hughes INTEQ
Houston, TX

Results
Two laboratory (flow loop) tests of the pulser section have been conducted. The flow loop was configured to simulate downhole flow conditions, and the 2?-inch pulser design was demonstrated to develop reliable pulses with sufficient pulse height for data transmission.

The design of the alternator (power) section has been finalized, a laboratory prototype built and tested to verify the design, and manufacture of sub components initiated.

Benefits 
The new BCPM for the 2-inch steerable CTD BHA will considerably reduce the capital expenditure needed to drill a “smart,” yet relatively shallow land well. The BCPM eliminates the need for a coil with an electric wire connection, thereby enabling the use of a smart drilling BHA in locations where an electric line is not affordable. The elimination of the electrically supplied coil saves the cost of one complete reel, which could reach about $100,000. In addition, with land rig day rates averaging $30,000 or more, considerable operational savings may be realized if a change in reels (between wired and non-wired) is avoided for special operations, such as cementing or window cutting.

Background 
For drilling 3½-inch diameter development wells, CTD technology offers many benefits over rotary drilling. However, insufficient steering accuracy and low borehole quality are often experienced during CTD drilling. Electric wire is currently needed with coiled tubing strings to provide power to the steering tool and for downhole-to-surface communication. However, there are cases where a wired coil requires too high an effort or too great an expenditure.

This project builds on an existing wireless BCPM for a 6¾-inch tool that integrates an alternator-based electric power supply, an actuator to send information to the surface, and the capability to receive digital signals downhole.

Summary 
This project will build on the project performer’s experience in designing, developing, manufacturing, and operating measurement-while-drilling (MWD), logging-while-drilling, borehole telemetry, and various steering devices, including CTD assemblies. The project will develop and test a BCPM that complements the existing modular CoilTrak™ drilling BHA. The system will include a fit-for-purpose surface control system. The availability of the new modules will reduce operational costs.

Project tasks break down into two phases: the system design and the manufacturing and testing phase. The design phase consists of system concept evaluation, draft and detailed design of downhole components, and manufacturing decision.

The manufacturing and testing phase commences after a decision to proceed to manufacturing. This phase consists of manufacture of two prototype 2?-inch BCPMs, a surface control system, and field testing of the prototypes and evaluation of their performance.

Current Status (December 2008) 
This project has been completed and the final report is available below under "Additional Information".

Baker Hughes INTEQ has designed, manufactured, and now laboratory tested, three prototype 2-3/8” Bi-Directional Communications and Power Modules (BCPM) for its Microhole coiled tubing bottom hole assembles. This project is partly funded by the US Department of Energy, National Energy Technology Laboratory.

The BCPM contains an alternator that uses the flow of drilling fluid within the bore of the coiled tubing to generate electrical power for other Measurement-While-Drilling (MWD) and Logging-While-Drilling (LWD) components of the BHA. It also contains an actuator that can encode and transmit data from downhole to surface, and has the capability to receive and demodulated instructions from surface. This transfer of information uses pressure pulses in the flowing drilling fluid column inside the coiled tubing. Since all power generation is based on the drilling mud, the BCPM eliminates the need for an expensive coil with an electric wire connection and enables the use of a smart drilling BHA in locations where an electric line is not affordable.

Despite its very small size, the 2-3/8” BCPM is performing to specifications and will deliver MWD transmission rates similar to those used with larger diameter equipment. The prototypes were individually tested in the Flow Loop and their target upper and lower operating limits were validated. The prototypes were successfully integration tested in the target CoilTrak™ BHA at the Baker Hughes Flow Loop Test Facility without any major problems. While the test was not ideal due to the use of a conventional drill-string rather than coiled tubing, the tools functioned while drilling in the Test Well at Baker Hughes’ Oklahoma facility. The final test in the Baker Hughes Test Facility proved that the system functioned extremely well throughout its specified operating range when run through a 7000 foot coil.

Schematic of the BCPM MWD component. Controlled actuation of the main valve creates a positive pressure pulse. Digital information is encoded in a train of these pressure pulses. The turbine/alternator provides power to other MWD components in the BHA.

Funding 
This project was selected in response to DOE’s Oil Exploration and Production solicitation DE-PS26-04NT15480-2B, Microhole Breakout, August 2, 2004.

Project Start: February 1, 2005 
Project End: December 31, 2007

Anticipated DOE Contribution: $760,000 
Performer Contribution: $253,334 (25 percent of total)

Contact Information
NETL - Virginia Weyland (virginia.weyland@netl.doe.gov or 918-699-2041)
Baker Hughes INTEQ - John Macpherson, (john.macpherson@inteq.com or 713-625-6558)

Additional Information
Final Project Report [PDF-2.35MB]

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