rational artificial lift selection by mike berry

Michael R Berry, PE

Dwiggins Consulting, [email protected]

+1-405-694-9950

9/25/2015SIPES Continuing Education Seminar

mailto:[email protected]

Layman’s Guide to Artificial Lift

• Gas Lifto Put a bunch of holes in the tubing then pump gas down the

annulus and hope something comes out the tubing• Velocity Strings

o Just keep making the tubing smallero In the right well, you can just stop using scale inhibitor

• Plunger Lifto Just drop a plug down the tubing and it will float up on a gas

bubble – kind of like perpetual motion• Rod Pump

o Visualize on old western hand pump with a really long rod…• Progressing Cavity Pump

o Pulling those rods up and down is too much work, just rotate ‘em

9/25/2015SIPES Continuing Education Seminar 2

Layman’s Guide to Artificial Lift

• Hydraulic Piston Pumpo Rotating rods is ridiculous and only a Canadian would consider ito The problem is we are pulling the plunger from the top, let’s push

from the bottom instead!

• Jet Pumpo Just knock a hole in the bottom of your tubing and then squirt

water past it to the surface – no, really! It will work!

• Electric Submersible Pumpo Simply put a 4000 volt motor on an 8000’ extension cord in a well

full of pressurized salt water. What could possibly go wrong?


High Rate vs. Depth Capacity


Low Rate vs. Depth Capacity


Lift Methods by Cost• Free

o Natural flow• Practically Free

o Plunger lift• Cheap

o Gas lift w/ HP gas sourceo Progressing cavity pump on elec. motoro Rod pump w/ inventory pump jack

• Not so cheapo Progressing cavity pump on hydraulic driveo Rod pump w/ new pump jack


Lift Methods by Cost • Not cheap at all

o ESP on utility grido Jet or hydraulic pump on utility grid

• You are going to make your vendors very happyo ESP via generatoro Gas lift via compressoro Jet or hydraulic pump using engine power or generator


Natural FlowAdvantages Disadvantages

• Defers cash expenditures

• Puts less stress on the completion

• Flowing period can be extended by reducing flow conduit cross-sectional area

• Minimal wellhead foot-print w/ no moving parts

• May not provide optimum rate

• May be difficult to re-start flow if well dies


Gas Lift


Gas LiftAdvantages Disadvantages

• High rate• Very tolerant of high GLR,

sand, corrosion & doglegs• Relatively easy on

completions• Easy, forgiving operation• Small wellhead footprint

w/ no moving parts• Valves can be wireline

retrievable• Full bore tubing access

• Compressors can be noisy, expensive and hard to operate

• More economic on large scale projects (multi-well}

• Low drawdown (~0.1 psi/ft)

• Needs larger tubing / casing for high rates

• Doesn’t like high back-pressure or fluid viscosity (<15°API)

• Can be hard to optimize


Plunger Lift


Plunger LiftAdvantages Disadvantages

• Doesn’t require external energy

• Inexpensive installation & maintenance (rig generally not required)

• Tolerates high GLR & doglegs

• High drawdown• Keeps well cleaned of

paraffin deposits• Small wellhead footprint

w/ no moving parts

• Low rate (<200 bpd)o Need to maximize tbg/csg

• Has minimum GLR & static BHP requirements

• Doesn’t like solids or scale

• Requires surveillance to optimize

• Deviation limited to ~60°


Reciprocating Rod Pump


Reciprocating Rod PumpAdvantages Disadvantages

• Well understood lift method

• Widespread infrastructure

• High drawdown• Low OPEX• High system efficiency• Surface units can be

moved between wells• Rate easily adjusted

through stroke length and speed

• Rate capacity decreases with depth & tubing size

• Doesn’t like gas, sand or doglegs

• High initial CAPEX• Requires either utility grid

or maintenance of IC engine

• Large wellhead footprint w/ large moving parts

• Potential for stuffing box leaks

• IC engine can be noisy9/25/2015SIPES Continuing Education Seminar 14

Progressing Cavity Pump


Progressing Cavity PumpAdvantages Disadvantages

• Tolerates high viscosity• Can pump high sand

fractions (>30%)• High drawdown• Low operating &

capital cost• Can be very efficient• Low power

consumptiono Solar powered possible

• Moderate wellhead footprint

• Elastomers limited to ~250°F• Elastomers intolerant of high

API crudes (35-40°)• Doesn’t like high GLR or

doglegs• Rate capacity drops with

depth & tubing size• Realistic TDH around 6000’• Intolerant of being pumped off• Requires either utility grid or

maintenance of IC engine• Has moving parts at wellhead

and potential for stuffing box leaks

• IC engine can be noisy


Hydraulic Piston Pump


Hydraulic Piston PumpAdvantages Disadvantages

• High drawdown• Good depth capability

(15,000’ or more)• Easy to pull/run pumps• Unaffected by doglegs

or deviation• Can produce multiple

wells from a single surface installation

• Small wellhead footprint w/ no moving parts

• Doesn’t like solids or gas• Requires maintenance of

downhole PD hyd. pump• Requires maintenance of

surface hyd. pump• High pressure hyd. lines at

surface• Needs two flow conduits• Needs larger diameter

tubing/casing for high rates• Requires either utility grid or

maintenance of IC engine• Surf. hyd. pumps are noisy• IC engine can be noisy


Hydraulic Jet Pump


Hydraulic Jet PumpAdvantages Disadvantages

• High rate• Tolerates solids• No moving parts• Easy to replace/resize

nozzles• Unaffected by doglegs or

deviation• Can produce multiple

wells from a single surface installation

• Small wellhead footprint w/ no moving parts

• Low drawdown• Doesn’t like gas• Low power efficiency• Needs two flow conduits

minimum, three to vent gas• Needs larger diameter

tubing/casing for high rates• Requires maintenance of

surface hyd. pump• Requires either robust utility

grid or maintenance of IC engine

• High-pressure hydraulic lines at surface

• Surface hyd. pumps are noisy


Electric Submersible Pumps


Electric Submersible PumpAdvantages Disadvantages

• High rate, high drawdown

• Suitable for moderately deviated wells

• Useful for well testing• Small, wellhead footprint

w/ no moving parts• Can tolerate some gas

o <10-20% by volume at intake

• Can tolerate some solidso <6% by weight

• Can resist corrosion w/ proper trim selection

• High CAPEX & OPEX• Unforgiving operation• Doesn’t particularly like

free gas, abrasives, scale or high viscosity

• Rate capacity decreases with depth & casing size

• Requires robust utility grid or maintenance of generator

• Generators can be noisy• High voltage at wellhead


Artificial Lift Methods Limits


Why does lift method matter?• As production engineers our job is to maximize the

value of the properties we are responsible foro Yes, yes. Safely, legally, and in an environmentally friendly way

• This is NOT the same thing as maximizing the production rate or minimizing the lifting cost

• This means maximizing NPV, IRR, or whatever financial criteria we select

• When we select an artificial lift method we want to select the method that gives us the greatest financial return for the property


Don’t blindly maximize rate!• Is maximizing rate by drawing a well down to

the point you are damaging a formation or tearing up pumps, are you really making more money?o The answer could be yeso But, you must compare alternative economics


Don’t justify a lift installation on days to payout!

• Maybe you have a great well & you are destroying an ESP every 3 weeks but you can pay for a new one in a week.

• You are making money, but are you maximizing economics?

• A pump a week for that kind of well is maybe $250K/week. Four pumps is $1MM.

• Maybe you could have used that money for something else?


The most best time to consider a lift method?

• BEFORE YOU DRILL THE WELL!!!!• If you put a 12° dogleg in a well at 1000’, you

are had as far as any rod lift method goes• You may or may not be able to get an ESP

below doglegs greater that 10°• You need a “tangent” section with a dogleg

< 6° to land an ESP


Check your drillers’ heart health

• Tell them your high rate gassy wells need 7” production casing!o Smaller diameter casing/tubing restricts the

rate/depth capacity of all lift methodso ESP’s need room for the gas to bypass the

equipment. Otherwise the gas must be ingested.o Jet and hydraulic pumps require at least two flow

conduits. If you want to vent gas so the pumps don’t have to ingest the gas, you need an extra flow path. i.e. bigger casing!


Don’t take no for an answer, at least not without an argument!

• Run the economics• Educate your drillers• These days wells are drilled in 3 weeks or less• Production has to deal with them for 30 years

or more• If someone tells you time value economics

means nothing matters after X years, tell them, “Well then, I guess we’ll just cut the reserves off at X years too!”


So how do we rationally select an AL method?

• Understand well performance• Eliminate methods that are not feasible• Project production & expenses for each of the

remaining methods• Run the economics• Evaluate alternate scenarios

o Maximize rate with ESPs / gas lift / jet pumps vs. flowing until rates drop into the rod pump range for example

• Don’t be afraid to think big, consider central compression / hyd. power / elec. power


Reasons not to use a technically feasible lift method

• Government restrictions (BLM, EPA)• Civic restrictions (residences, crop circles)• Support infrastructure (nearest shop)• Your personnel (will you need body armor?)• Their personnel (are they competent?)• Future lift methods• Utility restrictions (power limits)• Ambient conditions limitations (extreme

heat, cold)9/25/2015SIPES Continuing Education Seminar 31

What about your commitment?

• The most critical requirement for the success of a new lift method is to get you field personnel on boardo Make your case to the field and get their buy ino Start with easier wells

• A new lift method is more work, it will mean more long days, it will mean more aggravation

• Will you take the time, do you have the time to help your field personnel to become proficient (past the first couple of installs?


Conclusion• Your best choice for artificial lift might not be the

method that gives you the highest production rate• Design process:

o Pick the methods that are capable of producing your wello Compare the economics of each viable methodo Pick the method with the highest return, adjusted for your

local circumstances• If this is a new lift method:

o Sell it to field operationso Don’t start with your most difficult well

• Provide continuous support/training for both old & new lift methods


Questions?


rational artificial lift selection by mike berry

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