9
The collar piece or stick typically will have a welded
flange or sleeve, fabricated to support a loaded line, that
seats on a collar foundation. Following borehole comple-
tion, including casing, the borehole collar will be finished
with an arrangement to bear the weight of a full transfer
line. As appropriate, the initial transfer line installation may
be done by the borehole drill, a work-over rig or a crane.
Sufficient stick-up at the collar may ease line handling after
initial installation.
If the system ventilation characteristics indicate such,
allowance for a vacuum break and/or pressure relief can be
built into the collar or sub-collar of the borehole, with an
appropriate fitting to the suspended line. Those features
also can be worked into a collar with a stick-up allowance.
Figure 2 shows a vent provided by using a conventional
lateral on an above-collar sub. Figure 3 shows a reduced
diameter collar insert, first discussed in Diameter: Slickline/
Dropline, which reduces wear in the upper segments of
the slickline and also shields the vent lateral from impact.
Collar inserts, typically one or two sticks (pipe lengths),
can be configured for placement and extraction using con-
ventional welded lifting eyes. Bolted arrangements also can
be used, typically blind bolted into the collar flange for
extraction.
As indicated in Figure 2, it is advisable to case infra-
structure holes for long service. A common approach is
to install a collar casing for drilling and subsequent hole
completion and system construction. Within that will be a
surface or soil casing running down to and seated in com-
petent bedrock. A final casing may be run to hole total
depth (TD), installed to control groundwater inflow and/
Figure 2. Concept sketch, borehole collar-suspended slickline
The collar piece or stick typically will have a welded
flange or sleeve, fabricated to support a loaded line, that
seats on a collar foundation. Following borehole comple-
tion, including casing, the borehole collar will be finished
with an arrangement to bear the weight of a full transfer
line. As appropriate, the initial transfer line installation may
be done by the borehole drill, a work-over rig or a crane.
Sufficient stick-up at the collar may ease line handling after
initial installation.
If the system ventilation characteristics indicate such,
allowance for a vacuum break and/or pressure relief can be
built into the collar or sub-collar of the borehole, with an
appropriate fitting to the suspended line. Those features
also can be worked into a collar with a stick-up allowance.
Figure 2 shows a vent provided by using a conventional
lateral on an above-collar sub. Figure 3 shows a reduced
diameter collar insert, first discussed in Diameter: Slickline/
Dropline, which reduces wear in the upper segments of
the slickline and also shields the vent lateral from impact.
Collar inserts, typically one or two sticks (pipe lengths),
can be configured for placement and extraction using con-
ventional welded lifting eyes. Bolted arrangements also can
be used, typically blind bolted into the collar flange for
extraction.
As indicated in Figure 2, it is advisable to case infra-
structure holes for long service. A common approach is
to install a collar casing for drilling and subsequent hole
completion and system construction. Within that will be a
surface or soil casing running down to and seated in com-
petent bedrock. A final casing may be run to hole total
depth (TD), installed to control groundwater inflow and/
Figure 2. Concept sketch, borehole collar-suspended slickline