Lecture12b_Basic Gaslift Sec 5 - Mandrel Spacing Design

7/15/2019 Lecture12b_Basic Gaslift Sec 5 - Mandrel Spacing Design

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Gas Lift

Production Technology

Lecture 12b: Gas Lift - Section 5

ecommen e ex : r c a e o s,

Kermit E. Brown, Volume 2a

PennWell Publishing Co, Tulsa, OK, 1980

Akim Kabir

Senior Lecturer

Department of Petroleum Engineering

Curtin University of Technology

Slide 1Section 5 - Mandrel Spacing DesignAug 2008


2/14

Gas Lift

Mandrel S acin in Continuous Flow Wells

Purpose of Spacing

eac e opera ng gas va ve , norma y an or ce va ve

Maintain single point injection at that point

Design to be flexible to accommodate future change in well parameters

Purpose of GLV Design

,

- To inject gas as deep as possible

- To conserve as much casing operating pressure as possible

- o ensure e we can e un oa e success u y

+Ensure all upper valves closure after the final point of injection is

established- o e a e o open a va ve w c -o pressure regar ess o e u ngfluid level in the tubing

Slide 2Section 5 - Mandrel Spacing Design


3/14

Gas Lift

Desi n Mandrel S acin Universal Method

On the graph paper

Draw the injection operating pressure

PRESSURE (PSI)

0

500 10000

(Pwh + 0.2 Pso)

gradient (from Pso)

Determine flowing tubing head

pressure and plot it on the graph paper

500

(FT

TVD)

e erm ne po n o gas n ec on(assume operating differential Pdiff=

100 psi) and calculate / trace operating

flowing pressure traverse

1000

1500

DEP

T Calculate surface pressure for designtbg. line Pwh + 0.2 Pso or Pwh+ 200

(whichever is greater)

To determine the desi n tubin

2000

pressure, draw the line starting from

the calculated surface pressure to

intersect the expected flowing gradient

line at the oint of as in ection

2500

3000

100 psi

3500

Mid

Perforation

Top Packer



4/14

Gas Lift

On the graph paper

0

500 10000PRESSURE (PSI)

Starting from FTHP draw the

static gradient line for the

500 50 psig

gradient) to intersect Pko line

Place the first mandrel at the

1000

1500(

FT

TVD)

point where the differentialpressure between the kick-offand unloadin radient is 50

2000DEP

T

psig2500

3000

3500

Mid

Perforation

op ac er



5/14

Gas Lift

Settin De th for Second & Dee er Mandrels Universal

On the graph paper0500 10000

PRESSURE (PSI)

s ng e s a c gra en ne othe completion fluid, draw a

parallel line from the intersection

500

and the tubing design line tointersect the available casing1500

H(

FT

TVD)

. .

operating pressure line.

Place the second mandrel at that

2000DE

P

po n

Repeat the above steps until

reaching the point of injection or

2500

3000

Inj Point

below

3500

Mid

Perforation



6/14

Gas Lift

Pdiffand Mandrel Spacing Around Inj. Depth

Pdiff= Operating Differential

It is the difference between0

1000PRESSURE (PSI)

opera ng gas n . press. a ep

(Pc) and established flowing tubing

pressure at depth (Pt)

500

injection should be close enough to

ensure a maximum allowable

differential of 100 psi1500

H(

FT

TVD)

Valve spacing has to be atcertain interval (minimum) to

assure a maximum Pdiff

2000

100 si

Pdiff (Inj Point)DE

P

Pdiff= GfDv

Gf= Flowing grad. below inj point

Dv = distance between valves

2500

3000

Example, Pdiff= 100 psi

Gf= 0.4 psi/ft3500Mid

Perforation


.


7/14

Gas Lift

Pdiffand Mandrel S acin Around In . De th

For lar er s acin max Pdiffis0

1000PRESSURE (PSI)

higher; therefore, everything elseremaining the same, have toinject at shallower depth i.e.

500

lower lifting efficiency / lower Qliq

If only valves 1 and 3 wereresent max. o eratin

1000

1500(

FT

TVD)

differential could be as high as200 psi, before transfer to thenext lower valve occurs

2000Pdiff (Inj Point)

DEP

T

On the other hand, too closespacing will cause multi point

2500

3000

100 psi250

250

Valve #1

Valve #2

Valve #3 not see sufficient pressurereduction to close

3500

Mid Perforation

Top Pac er



8/14

Gas Lift

Desi n the Dee est Mandrel Universal

On the Graph Paper

Bracket the valve spacing to0


permit a valve to be located atthe point of gas injection and

with at least one valve below this

500

pont. evera more va ves maybe placed below this (abovepacker) depending on expected1500

H(

FT

TVD)

u ure we parame ers

If the last few valves are tooclose, space them at an interval

2000DE

P

somewhat less than max valvespacing derived from design Pdiff

(but > ~100)

2500

3000

Inj Point

3500

Mid

Perforation



9/14

Gas Lift

Example of Mandrel Design for PPO Valves

0


500

1000

1500

TH(

FT

TVD

2000DEP

2500

3000 To Packer

100 psig

3500

Mid

Perforation



10/14

Gas Lift

Exam le of Mandrel Desi n for IPO Valves

On the graph paper

PRESSURE (PSI)

0

500 10000

Methodology remains thesame except the followings:

To determine the next deeper mandrel

500

rom e man re ownwar , e

starting point is the intersection point of

the expected flowing gradient and the

mandrel line

TVD)

1500PPO

approximately 20 psig for each valve toassure closure of upper valves once the

lower valve is passing gasDEPTH

(F

2000

IPO

2500

3000

100

3500

Mid

Perforation

Top

Packer



11/14

Gas Lift

GA SLI F T V AL V E S I N ST A LL A TI O NASLI FT VAL VES I NSTALLATI ONREQUEST FORM

TO : Well servi ces Engi neer DATE : May 13, 200 3FROM : . H. Kabir, PM9 Snr Surveill ance Engi neer

CC : Well Fil e ExpectedSUBJECT : Programf or Gaslift Val ve Change Ki ck-off pressure 1, 450 psi a = 9, 904 kPag

LOCATI ON : Ti nggi- A Desi gn Gaslift rat e 1. 5 MMscf/ d = 43 k m3/ dWELL NO. : TGA-28 PI desi gn 10 STB/d/ psi

Desi gn li q rat e 1, 400 st b/ d = 265 mKL/ day

,

Wat ercut 1 %FGOR 730 scf/st b

CURRE NT S T AT US P ROP OS E D NE W V AL V E S S P E CSCURRE NT ST AT US P ROP OS E D NE W V AL V E S S P E CSGL M # DE PT H DE PT H GL M Pkt GL V Model GL V PT RO GL V Model GL V PT RO Pd

t - R K B - R K B z e n Ty pe Prt Sz e si g Ty pe Prt Sz e si g 60F si g 1 2256. 5 687. 8 1 Dummy - - n/ a GL V P O BK-1 16 1370 1170

* GL V P O B K 1. . ummy - - n a GL V P O BK-13 7379. 2 2249. 2 1 Dummy* - - n/ a Dummy e w 4 8062. 3 2457. 4 1 LV IPO BK1 20 1659 GL V P O BK-1 20 800 11235 8714. 9 2656. 3 1 LV IPO BK1 20 1463 GL V- No Ch an ge B K- 1 20 1460 l at ch broken


gNote* Dummy vlves leaking - detected


12/14

Gas Lift

P R O P O S E D N E W V A L V E S S P E C SGL M # DE P T H GL V Mo d el GL V P T R O P dt - R K B Ty p e Prt Sz e si g 6 0 F si g

1 2256. 5 GL V P O B K - 1 16 1370 1170GL V P O B K - 1. GL V P O B K 13 7379. 2 D u m m y e w GL V I P O B K 1. GL V P O B K - 15 8714. 9 GL V- No Ch a n g e B K- 1 20 1460 l at ch broken



13/14

Gas Lift

Information Re uired for Desi n

As much of the following information as possible should be obtained:

1. Tubing and casing

2. Mid-perf. Depth3. Oil API

4. Formation gas-oil ratio (GOR)

5. Injection gas and formation gas specific gravity

6. Expected daily gross production

. a er-cu

8. Water specific gravity9. Flowing well tubing head pressure

10. Available casin head ressure

11. Available lift gas injection rate

12. Productivity index or IPR Curve

13. Reservoir Pressure. o om o e empera ure

15. Flowing tubing head temperature

16. Type of reservoir with expected depletion performance



14/14

Gas Lift

Mandrel Spacing DesignGiven the following well data:

Find the following:

1) Location of the op. valve

Tubing Size (ID) = 3 in.

Casing Size (ID) = 8.681 in.

FTHP = 100 psig

3) Gas volume needed

4) Valve port size

=

Gross Production = 4000 b/d

Water-cut = 0 %

GOR = 200 scf/bbl

Formation/Lift Gas S.G = 0.65Avail. Csg Head (Kickoff) = 1300 psig

Assume Pso = 1200 psig

To acker de th = 6500 TVD ft

Reservoir Press. = 2900 psig

Temp. = 160 F

Depth = 8000 TVD (ft)

Productivity Index = 5 b/d/psi(assume st. line IPR)

Completion fluid gradient= 0.5 psi/ft

Geothermal gradient = 1.4 F/100ft

Gas Compr. Factor Zavg = 0.88 @ Avg Temp


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Lecture12b_Basic Gaslift Sec 5 - Mandrel Spacing Design

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