English Edition (6 MB pdf) - Saudi Aramco

orehole fluids. This tool can be configured so that its
diameter is 2.4” or 4.1” by the installation of interchangeable
pads. The eight arm design and the interchangeable pads
allow the tool to acquire images in holes as slim as 3” or as
large as 13”, and still allow for borehole coverage similar to
larger imaging tools currently on the market. The tool can
also be deployed using a number of conveyance techniques
not possible with conventional sized imaging tools. Figure 2 is
Fig. 1. A small diameter formation testing tool.
a photo of a small diameter microresistivity imaging tool
(2.4” version) in the open position exiting open ended
drillpipe.
Conveyance Options
The modern small diameter logging tools previously described
have been designed to obtain quality petrophysical data and also
to be integrated into efficient deployment systems. Figure 3
outlines the conveyance options available for small diameter tools.
Two features of small diameter tools make them suitable
for deployment in a wider range of scenarios than larger
conventionally sized logging tools. These include:
Size. With their slim design, these tools can be run in hole
(RIH) through standard tubing, such as drillpipe (for wells
with difficult hole conditions) and production tubing (for
wells that have been completed), making access into
wellbores efficient and less risky. The slim design also
allows for access into wells as slim as 3”. With their short
design, these tools are able to navigate wells with high
dogleg severity, such as ultra slim sidetracks. With their
lightweight design, these tools are easier to push with well
tractors and coiled tubing (CT), improving the effectiveness
of these conveyance methods.
Low Power Requirements. This feature allows these
logging tools to be run free of a wireline. Without a
wireline to transmit power to the tools, the logging
operation can be performed in several ways that will
reduce the time required to log, and risk with respect to
well control and equipment damage.
The two key features described above expand the number of
ways small diameter tools can be conveyed into a well. Listed
below are the main conveyance techniques that are possible
with these tools along with a brief description of the technique.
• Wireline 3 - Widely used method of conveyance of
logging tools by electric cables.
Fig. 2. A small diameter microresistivity imaging tool (2.4” version).
SAUDI ARAMCO JOURNAL OF TECHNOLOGY SUMMER 2010 61