American Oil and Gas Reporter - December 2020 - 51

SpecialReport: Well Completion Technology
wireline-to-frac/frac-to-wireline.
Placed between the frac head and
wireline lubricator, the automated system
minimizes the inefficiencies and risks inherent in traditional plug-and-perf processes. The entire system can be operated
from a control cabin or remotely via an
Internet connection. Hydraulic valve actuation is controlled with a computer
inside the valve cabinet and by a laptop
in the cabin. The quick-connect latch attaches the lubricator to the frac tree
without having personnel working at
height, and the integrated ball launcher
eliminates the need to enter the red zone
to drop balls.
The three-chamber valve provides the
ability to equalize pressure between the
lubricator and the well without operating
the gate valve, letting wireline-conveyed
perforating guns and frac plugs easily
pass between the surface and wellbore.
The flow iron is kept under pressure
throughout the completion process to
eliminate frac iron pressure testing as
well as pressure cycling that is a contributing cause of leaks. By significantly
reducing the need to operate the stack
gate valves (in many cases operating only
a few times per well during the entire
job), well cost is reduced by lowering
frac stack greasing requirements by 90%
or more, minimizing stack valve damage
and repairs, and eliminating gate valve
failure occurrences by removing the need

to shut in the well at each stage.
The dual valves within the three-chamber design provide two, 15,000-psi barriers
to control pressure. The valves operate in
one direction and seal against wellbore
pressure from below. An O-ring provides
a low-pressure seal, and a metal-to-metal
seal engages at higher pressures. The valve
system is instrumented to provide pressure
readings for each of the three chambers to
verify proper operation and detect leaks.
The valves cannot be opened unless
pressure is equalized above and below
the valve within 5 psi, preventing accidental pressure releases. The valves also
are designed so they cannot kink or sever
the wireline passing through the chambers
in the event they are closed on the wireline,
eliminating the risk of a common unplanned event that can add significant
time and cost to well completion.
Sequential Operations
Figures 1A and 1B illustrate the sequential operations of the multi-chamber
valve mechanism while deploying balls
and running wireline-conveyed perforating
guns and frac plugs. The dual valves
isolate the upper chamber, the load lock
chamber (equalization chamber), and the
lower chamber. When the lubricator is
attached to the latch, the lubricator and
upper chamber are at atmospheric pressure,
and the two lower chambers are at well
pressure. Then the upper chamber and

lubricator are filled to equalize well pressure. At this point, the two valves are
opened and wireline can be run to convey
plugs and guns.
After perforating, the guns are retrieved
and both flapper valves are closed. The
lubricator and upper zone are bled down
to atmospheric pressure, the lubricator is
removed, and the ball can be dropped to
rest atop the upper flapper. The ball is
conveyed by lowering pressure in the
load lock chamber to open the upper
valve. After the ball has entered the load
lock, the upper valve is closed to equalize
the load lock to well pressure. The lower
valve can then be opened to release the
ball down hole. The load lock is dry
during this sequence to avoid premature
dissolving of dissolvable balls.
The quick-connect latch is fully automated and operated from the control
center. At 22-inches in height, attaching
the lubricator does not require personnel
in a man-lift in the red zone and saves
time by eliminating lubricator stabbing
and winging. The valve provides a double
barrier so that a night cap is not required
for well control. The iris-style latch secures
the lubricator with 360-degree contact
and has redundant safety features, including
the ability to test seals and a lock to safeguard against accidental detaching through
human error or hydraulic pressure loss.
An internal drain prevents water from
spilling to the ground when the lubricator

FIGURE 1B
Multi-Chamber Valve Operation during Wireline Deployment

Upper
Chamber
Upper
Valve
Load
Lock
Lower
Chamber

Lower
Valve

Frac
Stack

* Fill and Equalize
Lubricator

* Lubricator at
Well Pressure

* Operate Valves
* Run Plug and Guns

* Retrieve Guns and
Operate Valves

* Bleed Down
Lubricator

* Detach Lubricator
* Drop Perf Ball

Atmospheric Pressure
Well Pressure

DECEMBER 2020 51

American Oil and Gas Reporter - December 2020

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