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Oilfield Technology
January
2016
data collected required the development and application
of acoustic telemetry technology in a cased-hole
environment. This technology provides the capability to
acoustically communicate and control downhole tools in
real time. To control the entire well testing operation, this
technology uses bidirectional communication capability
and real time data transmission to and from the downhole
tools. The combination of real time gauge data with the
capability to actuate the tester, circulating valve, and
downhole samplers allows for the entire control of a DST
operation and provides the required feedback of tool
position and operational status. Using these capabilities,
the complete well test can be performed with a reduction
or minimisation of potential operational uncertainties.
The capability to control tools using the real time
acoustic system provides significant advantages and
operational options. Downhole tools can be controlled
without application of annulus pressure, something not
possible with the use of traditional DST tool systems. In
addition, the use of acoustic-telemetry-controlled tools
are not limited because of casing pressure restrictions or
limitations required to space out rupture disks (RDs).
The technology is powered by a telemetry system
that is a battery-powered wireless system designed to
be deployed during drillstem testing (DST) operations.
This platform supports the entire system. The system
generates acoustic energy to transmit real time data to
the surface via the tubing wall (Figure 4) and includes a
package of gauges equipped with quartz crystal sensors
to provide accurate downhole pressure and temperature
measurements. These gauges operate in both
memory and in real time mode. The use of
wireless sensors and acoustic transmitters
enables bidirectional communication between
downhole tools and the surface. As mentioned
previously, the system also provides real time
data, allowing more informed and faster decisions
and more accurate characterisation of reservoir
formations through pressure and temperature
measurements and acoustic control of downhole
samplers as well as the tester/circulating valves
and data analysis.
The wireless telemetry system has already
been deployed in several well-testing operations
worldwide, facilitating operator and service
company decisions based on its capability to
provide
real time downhole data and allowing
qualitative determination of the number of
samples collected and the basic fluid composition
of samples collected at downhole conditions.
These capabilities led to reduced testing
uncertainties and communicated true real time
critical information to reservoir engineers.
Since information is the key objective of testing
operations, the system provides a powerful
Figure 5.
Burner under test.
Figure 6.
Typical configuration of awireless job.
