Performs buckling calculations of a pipe inside a wellbore
or pressure-control stack. This software is intended for
engineers, and uses Excel as the user interface. A user must
have an engineering background and a working knowledge of Excel
to use the software.
The example on the right demonstrates the capabilities
of the software. 2-3/8" tubing with a
4-3/4" packer is being snubbed into a well
through a stripper. The stripper appears as a purple
horizontal line. The pressure below the stripper is 5,000
psi, and there is 4,400 lbs of stripper friction. At the
top and bottom of the packer there is a thread relief,
causing higher stresses in these areas. As the BHA moves
downward it buckles until the packer contacts the 7
1/16" ID lubricator. There is a significant wall
contact force (WCF) at the point the packer touches the
lubricator. The first 2 plots show the string (red)
inside the well control stack (black), looking at it from
the Y and Z directions. Note that the vertical direction
is X. Also note that the scale length of 50' in the X
direction and ±4" in the Y and Z directions
causes the string to be distorted. The third plot shows
the maximum radial displacement (RD) along the length of
the string. This RD may be at any rotational orientation.
The fourth plot shows the wall contact forces. There is a
spike in the wall contact force where the packer touches
the lubricator. The fifth plot shows the maximum Von
Mises stress and the yield stress. In this case there is
a point at about 14' in which the Von Mises stress
exceeds the yield stress, and thus the string would
likely bend. |  |
 | The model can also output values versus time, as shown
in the following figures. The maximum Von Mises stress along the entire length
of the BHA is shown versus time. The buckling continued
for the first 5 seconds but then stopped as the packer
approached the stripper. The sharp increase in
compressive force and Von Mises stress near the end of
the simulation occurred as the bottom of the packer was
pushed into the stripper. The following figure shows the
corresponding displacement and compressive force. |