American Oil and Gas Reporter - June 2018 - 80

SpecialReport: Artificial Lift Technology
Increasing well productivity is undoubtedly the largest lever
for improving well economics, and wireless technologies can
provide the operational backbone to achieve efficiency and sustainable cost savings. Wireless technologies help operators
reduce costs through efficient facility construction and scalable
architectures, delivering future flexibility for field developments
and production optimization. Operators that standardize on
wireless capabilities can improve production, reliability, emissions
and safety, and react quickly and decisively to mitigate production
issues or capitalize on field development opportunities.
Moreover, when applied as part of a broader strategy with
complementary technologies such as advanced artificial lift optimization and produced fluids management software, wireless
capabilities give producers the means to dynamically respond
to changing well production compositions and flow patterns to
maximize production and enhance profitability. That is critical
given many resource plays' operational constraints, including
lift gas availability, limited compression horsepower, separator
capacity, water handling capacity, sales line capacity and more.
A lack of information about well operations constitutes the
most common cause of unmet production goals. Some critical
wellheads on a pad may have automated monitoring, but the
cost barriers to implementing traditional automation and control
solutions mean many wells do not. Cost-effective wireless
solutions make it possible to remotely monitor and control production, helping operators to meet their production goals while
continuously optimizing well operations, reducing environmental
and safety incidents, and streamlining operations and resource
allocation in the field.
Realizing these benefits is not simply a matter of access to
well data; it is about having the right data at the right time to
make quick and informed decisions. Some of the most fundamental measurements for onshore tight oil and shale gas wells
are tubing, casing and bradenhead pressures. Like blood
pressure in the human body, these data provide a reading of a
producing well's health at any point in time and indicate
potential problems that can lead to downtime. Adding measurements of injected gas, chemical injection, electric submersible
pump, rod pump and plunger lift well dynamics greatly improves
well performance visibility.
Wireless pressure transmitters provide accurate, around-theclock monitoring of casing/tubing pressures and chemical tank
levels. Flowing tubing pressure is a measurement that production
engineers typically check on a daily basis along with production
volumes to analyze well performance. A sudden or dramatic
drop in tubing pressure signals that a well has encountered a
problem. Casing pressure measurement monitors the annular
space between the tubing and casing, and a pressure build in the
annular space indicates a potential tubing leak. Bradenhead
pressure is another vital measurement that can identify a well
integrity issue.
80 THE AMERICAN OIL & GAS REPORTER

Artificial Lift
At the heart of any production operation is the artificial lift
system. In shale gas and tight oil plays, artificial lift performance
is challenged by highly variable production rates and multiphase
production flows consisting of varying percentages of liquids
and gas. Depending on well conditions and flow profiles,
operators are using rod pumps, electric submersible pumps, jet
pumps, multiphase pumps, plunger lift, gas lift and other forms
of artificial lift. The most important measurements vary by lift
system, but the main goal for any artificial lift solution is to
maximize production while minimizing capital expenditures,
maintenance and energy use.
For example, the key measurements for rod pumping are
motor temperature, motor vibration, hydrocarbon leak detection
and backpressure control. On the other hand, the key measurements
for plunger lift are wellhead pressure; bradenhead pressure; gas
line pressure, temperature, differential pressure and flow; liquids
line pressure, temperature and flow; vibration monitoring and
plunger detection.
New technology has streamlined plunger lift monitoring and
control. Technologies such as smart automation and online data
management allow operators to monitor and control plunger lift
systems remotely, without regular field visits. Wireless sensors
can be used to notify plunger arrival at the wellhead, with a late
plunger indicating problems such as a potential timing issue.
Once the plunger arrives, a remote terminal unit can control a
flowline choke valve to optimize well output.
Accurately measuring flow on a gas wellhead that utilizes a
plunger lift system can be a formidable challenge, and one with
significant financial consequences if not done properly. Although
a plunger lift system solves the problem of resuming the flow
of gas in mature wells, it creates its own set of challenges. With
every plunger cycle, the system subjects flowmeters to large
pressure spikes with wide flow rate variations. As the plunger
cycle repeats, it makes it impossible for conventional transmitters
to measure the flow of gas accurately. Utilizing a highly accurate
multivariable pressure transmitter with extended range capability
allows operators to increase wellhead production, capture gas
flow cycle in its entirety, and avoid lost profits.
Smart automation can go a step further by providing realtime adjustments of various control parameters to maximize
production with virtually no operator intervention. One typical
example is its ability to react to flow rates that drop below the
rate needed to lift fluid from a plunger lift gas well. Critical
velocity, as determined by the well-known Turner-Coleman
equations, is correlated to the critical rate necessary to lift
fluids from a wellbore. Flow rates below the critical rate cause
liquids to accumulate in the well to the detriment of gas
production. Local automation devices can perform the required
calculations consistently and end a plunger lift cycle before the
gas flow drops below this important value.
Gas lift is growing in popularity in both oil and liquids-rich

American Oil and Gas Reporter - June 2018

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