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5
Microhole Smart Steering
and Logging-While-Drilling
System
DE-FC26-03NT15473
Goal
The overall goal of this project is to pro-
vide a modular coiled tubing drilling
(CTD) system that allows operators to pro-
duce existing U.S. oil reservoirs in a much
more effective way than is possible today.
The objectives of this project are to design
and build 1) a smart drillbit steering motor
integrated with a high-performance down-
hole 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.
Performer
Baker Hughes INTEQ
Houston, TX
Results
Project accomplishments include the
development and evaluation of a number
of rib steering motor (RSM) design con-
cepts, and the selection and approval of a
final design. This design is now undergo-
ing final manufacture, and assembly of the
first of two prototype tools is underway
prior to expected field testing in the first
quarter of 2006.
Project accomplishments for the magnetic
propagation resistivity (MPR) tool include
the development of test bench devices and
software modeling, which indicate that a
resistivity tool employing both
400-KHz and 2-MHz frequencies can be
deployed in a 2
3
/
8-inch design. A
mechani
-
cal design was realized over a couple of
iterations, and two prototype tools are cur-
rently in manufacturing. It is expected that
the tool will meet all project goals.
Benefits
The advanced drilling, steering, and log
-
ging bottomhole assembly (BHA) is
expected to enable faster drilling,
increased well-path accuracy
, improved
hole quality
, and longer horizontal sec
-
tions. The improvements in drilling and
L
WD will lead to increased production
while decreasing the number of wells.
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, lat-
eral deep perforations, and well deepening
all can improve recovery of domestic
resources.
If this technology is developed and
deployed, as many as 5,000 new or re-
entered wells per year are possible.
Background
State-of-the-art BHAs for CTD of 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 equip-
ment.
Also absent in the currently available CTD
BHAs for microholes is a suitable LWD
tool. In order to keep the well within the tar
-
get zone and above the oil-water contact,
resistivity measurements taken during the
drilling process are needed to provide
instantaneous information about the dis-
tance 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 hydro-
carbons along the well path.
Summary
A 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 com-
mercially 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.
An MPR tool is being developed for
microholes that will allow true real-time
geosteering with instantaneous steering
actions based on resistivity (and gamma)
measurements.
Current Status (January 2006)
Both components of the project, the RSM
prototype and the MPR prototype, have
been designed, have passed design
reviews, and are currently in manufactur-
ing and assembly. Once assembled, the
prototypes will be extensively lab-tested
prior to field trails. A special short-radius,
3-inch, bi-center PDC bit has been
designed by Hughes Christensen for initial
field trials, which are expected to occur
March 2006.
Schematic of the 2
3
/
8-inch rib steering motor being developed in this
project.
Project Start / End: 10-1-04 / 3-31-06
DOE / Performer Cost: $738,667 / $183,417
Contact Information:
NETL – Sue Mehlhoff (sue.mehlhoff@netl.doe.gov or 918-699-2044)
Baker Hughes INTEQ – John Macpherson (john.macpherson@inteq.com
or 713-625-6558)
Steering rib
Bearing assembly
Drive sub