1059_3 - Shell --- PAIL Controller

8/10/2019 1059_3 - Shell --- PAIL Controller

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Experience with Plunger AssistedIntermittent Lift (PAIL) in a Shell

Operation

Charlie Moncur - Shell Global Solutions (author)Jim Hall SIEP EPT-REP (presenter)

ASME G/L Workshop Rio de Janeiro 2005


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Agenda

A brief history of intermittent lift in Shell Problems encountered with wells and equipment More recent success with Plunger Assisted

Intermittent Lift Future Application of the technology in Shell Fieldware Intermittent Gaslift Module


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History in Shell

Earliest records of intermittent lift trials date for 1960s Tried in a number of Shell operations unsuccessfully.

Considered an art not a science. Too many negative aspects not seriously pursued. Re-examined in mid 80s Camco, Ferguson

Beauregard/DAPSCO equipment trials mixed results.

Re-engineering exercise with DAPSCO in mid 80s. Successful from a mechanical point of view. Well control and operation still problematic. Late 90s final problems addressed and solved by Parkburn Well

Management Systems Ltd. Viable artificial lift application but not actively pursued further by

Shell.


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Principle Problems Encountered

Mechanical damage to plungers poor cycle control. Electrical equipment certification.

Pressure surges to production facilities - trips. Destabilization of well control cycle by variation in gaslift

pressure and flow line pressure. Large drawdown on gaslift system destabilize compressors Time consuming to restart after field trip. Poor understanding of well cycle and operation by field staff. Control and optimisation manpower intensive. Applied to problem wells probably worst candidates vain

hope No real commitment an interesting field trial file and forget.


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Target Wells

10 wells equipped and trialed with PAIL (3 vendors). All Problem wells unable to lift economically with beam

pump too low production for ESP. All wells in field traditionally converted from continuous

gaslift to beam pump. Wells with Wax/HGOR low volume producers - reservoir

pressure 400 to 800 psi Wells to be closed in if no other lift method could be

found The worst of the bunch!


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Case Study 1Well original completed as beam pump. Extremely waxy production declined

from130 bpd to 25 bpd very rapidly. Required 7 well pulling hoist entries per year to

keep

well pumping. Each entry 30 joints of tubing removed for de-waxing.Down time waiting on the hoist significant.

DAPSCO Singapore PAIL systems installed. Sustained low production but atreduced rate.

Parkburn Well Management Systems Ltd. PAIL control system fitted.Well on steady production at 125 bpd. No operator intervention .Well performance vastly improved over beam pump.

Control Unit

Combination Flexible Pad & Wobble Ring Plunger


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Case Study 2

Well converted form continuous gaslift to beam pump.Re-converted to PAIL unsuccessfully. Reverted to continuous gas lift.Parkburn Well Management Systems Ltd control system fitted to well. No operator intervention.Sustained optimised production with vastly reduced gaslift.


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Case Study 3 (Non Shell Site)(Complex Application)

The well was a high GOR producing from a thin oil rim of a gas field. Extremely waxy and produced on beam pump.The well was capable of natural flow but operated with limited draw down to restrict gas influx into the well and the oil gathering system.The well produced at a rate of 35 bpd with casing gas routed back into the flow line.Pressurization of the oil gathering system with increased energy costs for all the other beam pumps in the fieldThe gas from the beam pumps was ultimately flared.

Gas cap gas was produced from gas wells in the field to provide fuel for a 9Mw power plant for a gas well.A 2 7/8 PAIL system was installed which included multiple surface flow line valves. This allowed free gas to be directedto the gas gathering system and oil to be segregated at the wellhead and sent to the oil-gathering network.

The well had sufficient energy to lift the plunger and fluid column without the assistance of gaslift

Cycle pressures between 850 and 450 psig. With the high well energy available there was a danger of plunger damage.This was negated by the control system, which ensured that the plunger always had a fluid column preceding it.The control programme detected the imminent arrival of the liquid slug and switched production from the gas gathering system to the oil system.The reverse operation took place as the control unit saw the arrival of the plunger. Tail gas was blown down again to the gas gathering systems.Gas flow rate was also maintained constant to ensure stability of the process plant.Process trips were also reduced. As all the well formation gas is now routed to he power plant the demand on gas wells was reduced( 750 Mscf/d). Electrical energy for the beam pump was also saved. Well bore de-wax operations were eliminated.

Oil production was increased form 35 bpd to95 bpd

Dual Flow Line Control Valves

Customer BenefitsIncreased oil productionReduction in oil gathering pressure

Reduced beam pump energy load.De-wax of well eliminated.

No import of electrical power for wells.Continuous well monitoringReduced well testingReduction in gas cap productionReduced well maintenance

.

Well head


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General Layout

Simple Well Completion. Lubricator Single Side Outlet.

Wireline Quick Union Access. No Instrument gas electrical supply.UPS in control unit.

Managed by Single Operator. Environmentally friendly no subsequent

well pulling -minimal wireline no wellhead leakage - low profile low noise.

Low Maintenance plunger inspection- periodic GLV change out (3 to 4 years)


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Hardware Employed

Modified Lubricator Shock Absorber Single Outlet

Worcester Flow Control Valves(Flow line, Gaslift Supply)

Pressure Transmitters

( FTHP, FLP, CHP & Gaslift Supply) Proximity Switch PLC based control unit

Standard GLVs Standard Tubing Stop/Bumper

WORCESTER Control Valve

Lubricator Single Side Outlet

Wireline Quick Union


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Control Unit - Capability

HMI Operator Communication Auto restart unloading programme Fluid and gas produced per cycle/day Event logging remote communication Auto cycle optimisation daily liquid volume Auto gaslift injection modulation optimisation

(plunger velocity) Safety programme plunger protection

- GLV leakage FLP High incompletewell cycle plunger arrival before slug

Remote Communication Total Well Management Capability

HMI

0

5

10

15

20

25

0 5 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200Cycles per Day

G r o s s

P r o

d .

PI = 0.04

PI = 0.05

PI = 0.06

PI = 0.08

Test Sensitivity to PI. RP = 383 psig, Plunger Velocity = 800feet/min

Design Programme - Excel


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Insensitive to gaslift pressure variationInsensitive to flow line back pressure

Fully Automatic Self OptimisingESD/UPS capabilityRemote Communication

Auto restart after well tripLogging events, pressures, cycles

and volumes.Gas/Liquid Delivery ComputedGaslift Injected Computed

Control


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Pail Characteristics (1)C h a r a c t e r i s t i c P o t e n t i a l U s e

D o w n h o l e S e p a r a t io n o f F l u id s B e c a u s e o f th e c y c l ic m a t u r e o f t h e t e c h n i q u e o i l a n d l iq u i d ss e p a r a t e d o w n h o l e . T h e t u b i n g i s e f f e c t i v e l y a l a r g e s e p a r a t o r . T h e

p r o d u c e d o i l a n d g a s c a n b e s p l i t a t s u r f a c e b y t h e u s e t o 2 c o n t r o lv a l v e s a n d s e p a r a t e f lo w l in e s f o r o i l a n d g a s .

U s e s E x i s t i n g G a s l i f tI n f r a s t r u c t u r e

C o n v e r s io n t o b e a m p u m p r e q u i r e s s i g n i f i c a n t i n v e s t m e n t , h e a v y 3 - p h a s e p o w e r s u p p l y a n d r o u t i n e h o i s t m a i n t e n a n c e t o s e r v i c e t h eu n i t . C o n t in u e d u s e o f t h e g a s l i f t s y s t e m w i th i ts h i g h i n i ti a lC A P E X i n v e s t m e n t i s e c o n o m i c a l l y b e n e f i c i a l

L o w e r C o n v e r s io n C o s t s T h a nB e a m p u m p / E S P

C o n v e r s io n c o s t i s lo w e r . N o h e a v y 3 p h a s e s u p p l y , n o h o i s t p a d , n ol o c a l v e n t , n o p u m p u n i t f o u n d a t io n

L o w E n e r g y C o n s u m p t i o n U n l ik e a b e a m p u m p t h e r e i s n o s t a t i c h e a d i n th e t u b i n g , s u c k e r ro d sa n d s u r f a c e u n i t t o r e c i p r o c a t e . T h e e n e r g y e f f ic i e n c y o n P A I L i s a sa r e s u l t b e t t e r .

N o R o u t in e W e l l T e s t in g P A I L c a n s c o n t in u o u s l y m o n i t o r / r e p o r t i t s o w n p r o d u c t i o n a n di n j e c t io n r a t e s f o r g a s l i f t , t o t a l g a s a n d l iq u i d p r o d u c t io n .

C o n t in u o u s P r o d u c t i o nM o n i to r i n g

T h e c o n t r o l s y s te m l o g s p r e s s u r e s , v o l u m e s a n d e v e n t s o n ac o n t in u o u s b a s i s .

A u t o R e s t a r t A f t e r T r i p s A f te r a s t a t io n t r i p t h e w e l l c a n b e s e t t o a u t o r e s t a r t .

A u t o O p t i m i s a t i o n P A I L c a n o p t i m i s e g r o s s p r o d u c t io n a n d g a s l i f t i n je c t io n o n ad e m a n d o r a u to m a t ic b a s i s

I m p r o v e d D r a w d o w n T y p i c a l g a s l i f t i s u p t o 5 0 % d r a w d o w n P A I L c a n a c h i e v e + 8 0 %d e p e n d e n t o n r e s e r v o i r p r e s s u r e a n d P I .

T o l e r a n t to S a n d & F i n e s T o l e r a n t to l im i t e d s a n d a n d f in e s p r o d u c t io n e x p e r ie n c e f o r mS 3 3 7 .

W a x R e m o v a l

L o w D o w n h o l e M a i n t e n a n c eC o s t s

P l u n g e r m a i n t e n a n c e m i n i m a l , g a s l i f t v a l v e c h a n g e o u t 1 . 5 t o 2 . 5y e a r s i n t e r v a l

E n v i r o n m e n t a l l y F r i e n d l y S e a l s y s t e m n o s t u f f i n g b o x . L o w n o i s e . W i r e li n e m a i n t e n a n c e

n o h o i s t e n t r y

I n d e p e n d e n t C o n t r o l o f V a l v e s 2 f l o w l in e a n d t h e g a s l i f t in j e c t i o n l in e c a n b e c o n t r o l le di n d e p e n d e n t l y .


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Pail Characteristics (2)

Adaptive Control System The control system detects changes in the well performance andadjusts programme parameters automatically e.g. reduces/increaseinjected gaslift per cycle to keep the plunger at optimum velocity

Immediate Detection of MaleOperation

ESD function

Simple Well Design andEvaluation

Simple spread sheet for well candidate selection, design and initialoptimisation

Scaleable From 2 7/8 upwards. Casing plunger systems used in USA.

Deviation Insensitive Short plunger - dog legs not a problem. Can be used in highdeviation wells

No Dynographs & AcousticLogs

The control unit continuously logs well performance and can becoupled to SCADA.

Low Surface MaintenanceCosts

Surface maintenance limited to calibration of PTs and control valvemaintenance.

No Instrument Gas The control system is electrically powered either mains supply or24v d.c.

Ball Type Control Valves The control valves are ball types with choke capability. These present a large flow area when needed and capability to control pressure pulses seen by the Produciotn installations.


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Pail Characteristics (3)LCD Operator Interface Of extreme importance the operator must know what the well is

doing where it is in its cycle what has caused it to halt the pressure time trends input of control parameters.

ESD Capability Running in parallel with the control programme is an ESDmonitoring programme, which will halt the production cycle if anunsafe condition is detected.

Bean UP/Down Flexibility The well cycles can be adjusted from 1 cycle a day to maximumeither locally or remotely.

Pressure Surge Control Pressure surges to the production facilities are controlled by theWorcester flow line valve. This can be ramped open to bleed down

pressure and beaned back to control the flow line pressure as theliquid slug passes the wellhead.

Gaslift System Management With simple on/off control valves sudden large gaslift demands can be made on the gaslift supply network. With a large number ofwells on the system destabilization of the pressure can occur. Thisin turn feeds back to the well and destabilizes the well cycle.

Controlled Gaslift Injection Gas injection can be modulated to control the injection volume percycle.

Integrated with SCADA The PLC can communicate back to a SCADA system via a radiolink. Alternatively the control functions and optimisation could becentralized in Fieldware or a DCS system


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Future application of Technology in Shell

Many gaslifted fields in rapid decline continuous gasliftbecoming increasingly non-viable.

Most being converted to ESP or Beam pump. Still no acceptance of intermittent gaslift as a viable

artificial lift method.

One project currently looking at intermittent lift linked toreal time management and optimisation (Fieldware Implementation) Intermittent lift still low priority? No real penetration in Shell.


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Future Use of Intermittent LiftGoals? Wells produced to abandonment

under natural flow and gaslift regimes.

Single Completion in place from initialproduction to abandonment

Natural Flow

Continuous Gaslift

Time

Conversion to PAIL

Extend Life - PAIL

Inefficient CGL range

Replace Mech. Pump with - PAIL

Conversion to Continuous Gaslift

Conversion to Mech. Pumping

Mechanical Pump

Uneconomic MechanicalPumping Range

DrillNormal Abandonment


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Conclusions PAIL is a low cost, extremely viable and available intermittentlift method, that can allow wells to be produced to abandonmentwith gaslift. PAIL can lift small slug sizes with minimal galift from lowbottom hole pressure reservoirs. It can be made self managing and self optimising with minimaloperator intervention.Conversion of inefficient continuous lifted wells has yielded>50% increase in gross production and > 50% reduction ingaslift. It competes favourably in conversion cost with ESP and Beampump.

It competes favourably in life cycle costs with ESP and BeamPump.Whilst all experience to date is in onshore wells, application tooffshore wells is a viable and natural development of the PAIL

technology.

1059_3 - Shell --- PAIL Controller

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