Geology Reference
In-Depth Information
2.5.2 User interface.
In order to streamline routine analyses, a convenient Windows graphical
user interface is employed as shown in Figure 2.9a. The menu provides simple
text input boxes. Clicking “Simulate” launches the solver and automatically
produces the color graphical results for drillpipe and annulus shown in Figures
2.9b,c. Figure 2.9b clearly demonstrates that for low data rate pulsers, the
transmission efficiency is close to unity and not sensitive to pulser position
within the MWD drill collar. At 12 Hz, however, destructive interference can
reduce the wave energy available to support a viable carrier frequency.
Although changes in the bottomhole assembly, in pulser position within the
collar and in mud sound speed are not within the control of the operator, the
choice of frequency is, at least for operators of a next generation tool being
considered. The software can be used, as in Chapter 10, to evaluate optimized
higher frequencies which support higher data rate.
Figure 2.9a
. Graphical user interface.
Figures 2.9b,c.
MWD signal entering drillpipe (left) and annulus (right).
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