X hits on this document

59 views

0 shares

0 downloads

0 comments

4 / 14

Installing Plunger Lift Systems In Gas Wells

(Cont’d)

Revenue from Increased Production

Nelson Price Indexes

In order to account for inflation in equipment and operating & maintenance costs, Nelson-Farrar Quarterly Cost Indexes (available in the first issue of each quarter in the Oil and Gas Journal) are used to update costs in the Lessons Learned documents.

The “Refinery Operation Index” is used to revise operating costs while the “Machinery: Oilfield Itemized Refining Cost Index” is used to update equipment costs.

The most significant benefit of plunger lift installations is the resulting increase in gas production. During the decision process, the increase in production cannot be

measured

directly

and

must

be

estimated.

The

methodology for production varies methodology for

estimating this expected incremental depending on the state of the well. The continuous or non-declining wells is

relatively straightforward. In contrast, the for estimating the incremental production decline is more complex.

methodology for wells in

To use these indexes in the future, simply look up the most current Nelson-Farrar index number, divide by the February 2006 Nelson-Farrar index number, and, finally multiply by the appropriate costs in the Lessons Learned.

remove well bore fluids, acidizing to remove mineral scale and clean out perforations, fishing-out debris in the well, and other miscellaneous well clean out operations. These additional start-up costs can range from $700 to more than $2,600.

Operators considering a plunger lift installation should note that the system requires continuous tubing string with a constant internal diameter in good condition. The replacement of the tubing string, if required, can add several thousands of dollars more to the cost of installation, depending upon the depth of the well.

  • Estimating incremental gas production for non- declining wells. The incremental gas production from a plunger lift installation may be estimated by assuming that the average peak production rate achieved after blowdown is near the potential peak production rate for the well with fluid removed. A well log, like that illustrated in Exhibit 3, can be used to estimate the potential production increase.

In this exhibit, the solid line shows well production rate gradually, then steeply declining as liquids accumulate in the tubing. Production is restored by venting the well to the atmosphere, but then declines

again with reaccumulation of liquids. Note that production rate scale, in thousands of cubic feet

month,

is

a

log

scale.

The

dashed

line

shows

the per the

Exhibit 3: Incremental Production for Non-Declining Wells

Operating costs. Plunger lift maintenance requires routine inspection of the lubricator and plunger. Typically, these items need to be replaced every 6 to

12 months, per year. annually.

at an Other

approximate cost of $700 system components are

to $1,300 inspected

Step 3: Estimate the savings of a plunger lift. The savings associated with a plunger lift include:

  • Revenue from increased production;

  • Revenue from avoided emissions;

Additional avoided costs—well

treatment

costs,

reduced electricity costs, workover costs; and

  • Salvage value.

4

Document info
Document views59
Page views61
Page last viewedFri Dec 02 20:58:47 UTC 2016
Pages14
Paragraphs1459
Words6982

Comments