API Gas Lift Design - ALRDC

200 Pages·2007·8.09 MB·English

by  Cleon's Account

API Gas Lift Design
• API RP 11V6: Recommended Practice for Design
of Continuous Flow Gas Lift Installations ----
Using Injection Pressure Operated Valves
• By Sid Smith
2007 Workshop Clegg & Smith 1
INTRODUCTIONS
PLEASE TELL US THE FOLLOWING
INFORMATION ABOUT YOURSELF:
Name
Work Location
Job (role)
Number of Years Experience
Gas Lift Background
-
hands on
- previous training
2007 Workshop Clegg & Smith 2
Design Outline
• Introduction (20)
• Design Methods:
• General Design (20) .Constant Rate (30)
.Variable Rate (30)
• Inflow & Outflow &
.Intermittent (15)
…….Tubing (45)
.Equilibrium Curve (45)
• Facilities (15)
• API Example # 1 (45)
• Gas Inj. Pressure (15)
• Mandrels & Valves (30)
• API Example # 2 (45)
• Temperature (15)
• Gas Passage (15)
• API Example # 3 (45)
• Summary (15)
2007 Workshop Clegg & Smith 3
0. Introduction :API RP 11L6
• RP to provide guidelines, procedures
and recommendations. See other API
RP’s. (Also ISO documents)
• 1 Scope: Guidelines for continuous
flow using injection pressure valves
• 2 Intent: Maximize production and
. Minimize costs
• 3 Definitions
• 4 General Design Considerations
2007 Workshop Clegg & Smith 4
S.V.
Continuous Intermittent
2007 Workshop Clegg & Smith 5
Typical continuous flow gas lift installation
Injection gas into wing valve and then down
the casing-tubing annulus.
Well equipped with tubing, side pocket mandrels,
wireline retrievable gas lift valves and a
single production packer located just
above the producing zone.
Note: Upper gas lift valves closed and
gas enters gas lift valve near bottom.
2007 Workshop Clegg & Smith 6
4.1 General
• Complete system!
• Combination of concepts and experience
• Continuous flow gas lift has advantages
and limitations.
2007 Workshop Clegg & Smith 7
Continuous GL Strengths
• Flexible lift capacity
• Low surface profile
• Handles sand OK
• Compatible /SSSV’s
• Deviated holes OK
• Permits sounding
• Permits wire line op
• Easy BHP surveys
• Tubing fully open
• Permits PL surveys
• High GLR beneficial
• Dual lift feasible
• Low well R&M
• Tolerates bad design
2007 Workshop Clegg & Smith 8
Continuous GL Weakness
• High back pressure imposed
• Needs uninterrupted high pressure gas
• Compressor expenses often high
• Heading problem with low rates
• Potential gas freezing & hydrate problem
• Increased friction w/low gravity crude
• Valve interference & high inj. point
• Corrosion, Scale, & paraffin
• Efficient dual lift difficult
• Requires excellent data for good design
2007 Workshop Clegg & Smith 9
GL Design Guidelines
• Inject gas as deep as feasible
• Conserve injection pressure
• Ensure upper valves stay closed
• Be able to work down to bottom
• Check for ample gas passage
• Plan for changes in rate
• Avoid heading conditions
• Minimize costs & Maximize rates
2007 Workshop Clegg & Smith 10