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Installing Plunger Lift Systems In Gas Wells

(Cont’d)

removal allows the well to produce gas continuously and prevent fluid loading that periodically halts gas production or “kills” the well. Often, the continuous removal of fluids results in daily gas production rates that are higher than the production rates prior to the plunger lift installation.

Four Steps for Evaluating Plunger Lift Systems:

  • 1.

    Determine the technical feasibility of a plunger lift installation;

  • 2.

    Determine the cost of a plunger lift system;

  • 3.

    Estimate the savings of a plunger lift; and

  • 4.

    Evaluate the plunger lift’s economics.

Reduced paraffin and scale buildup. In wells where paraffin or scale buildup is a problem, the mechanical action of the plunger running up and

down

the

inside

the

tubing tubing.

may prevent particulate buildup Thus, the need for chemical or

swabbing treatments Many different types

may be reduced of plungers are

or eliminated. manufactured

with “wobble-washers” performance.

to

improve

their

scraping”

Lower

methane

emissions.

Eliminating repetitive

remedial treatments and well workovers also reduces methane emissions. Natural Gas STAR Partners have reported annual gas savings averaging 600 Mcf per well by avoiding blowdown and an average of 30

Mcf per year by eliminating workovers.

Other economic benefits.

In calculating the

economic

benefits

of

plunger

lifts,

the

savings

from

avoided

emissions

are

only

one

of

many

factors

to

consider in result from

the analysis. Additional savings may the salvage value of surplus production

equipment and work

and the associated reduction in electricity

over

costs.

Moreover,

wells

that

move

help operators ascertain whether a particular well would benefit from the installation of a plunger lift system. As an example, a well that is 3,000 feet deep, producing to a sales line at 100 psig, has a shut-in pressure of 150 psig and must be vented to the atmosphere daily to expel and average of three barrels per day of water accumulation. This well has sufficient excess shut-in pressure and would have to produce 3,600 scf per day (400 scf/bbl/1000 feet of depth times 3000 feet of depth, times 3 barrels of water per day) to justify use of a plunger lift.

Exhibit 2: Common Requirements for Plunger Lift Applications

  • Well blowdowns and other fluid removal techniques are necessary to maintain production.

  • Wells must produce at least 400 scf of gas per barrel of fluid per 1,000 feet of depth.

  • Wells with shut-in wellhead pressure that is 1.5 times the sales line pressure.

  • Wells with scale or paraffin buildup.

water continuously out of the well bore have potential to produce more condensate and oil.

Decision Process

the

Step 2: Determine the cost of a plunger lift system.

Costs associated with plunger lifts include capital, start-up and labor expenditures to purchase and install the equipment, as well as ongoing costs to operate and maintain the system. These costs include:

Operators should evaluate plunger lifts as an alternative to well blowdown and beam lift equipment. The decision to install a plunger lift system case basis. Partners can use the following decision process

as a guide to evaluate the effectiveness of plunger lift production wells.

applicability and cost- systems for their gas

Step 1: Determine the technical feasibility of a plunger lift installation.

Capital, installation, and start-up costs. The basic plunger lift installation costs approximately $1,900 to $7,800. In contrast, installation of surface pumping equipment, such as a beam lift, costs

and $52,000.

Plunger lift

include installing

the piping,

between $26,000 installation costs

valves, controller and power supply on

the wellhead

and

setting

the

down-hole

plunger

bumper

assembly

assuming

the

well

tubing

is

open

and

clear.

The

Plunger lifts are applicable in gas wells that experience liquid loading and have sufficient gas volume and excess shut-in pressure to lift the liquids from the reservoir to the surface. Exhibit 2 lists four common well characteristics that are good indicators of plunger lift applicability. Vendors often will supply written materials designed to

largest variable in the installation cost wire-line to gauge the tubing (check

is running a for internal

blockages)

and

test

run

a

plunger

from

top

to

bottom

(broaching) to assure freely up and down the

that the plunger will move tubing string. Other start-up

costs

can

include

a

well

depth

survey,

swabbing

to

3

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