horizontal well artificial lift simulation: unconventional ... · horizontal well artificial lift...

2018 Artificial Lift Strategies for

Unconventional Wells Workshop Cox Convention Center, Oklahoma City, OK

February 4 – 7, 2018

Horizontal Well Artificial Lift Simulation:

Unconventional Oil & Gas Well Case Histories

Dr. Anand S. Nagoo CEO, Pipe Fractional Flow | pipefractionalflow.com |

Director, University of Texas ALAMO Artificial Lift Consortium | tinyurl.com/alamo-invitation |

2 2018 Artificial Lift Strategies for Unconventional Wells Workshop

Oklahoma City, OK Feb. 4 - 7, 2018

Executive Summary

Can predicting the multiphase flow behavior improve understanding?

Whether production, reservoir, surveillance or artificial lift, predicting the

flow behaviors under different equipment and conditions can help in

better designing and optimizing wellbore multiphase flows

Our basic approach = simplify and interconnect flow pattern behaviors

and phase slippage using the analytical pipe fractional flow framework

to rapidly simulate phase holdups and pressure gradients

For more information/presentations/publications, visit pipefractionalflow.com/updates



Example Simulation Applications of PipeFractionalFlow

- Minimize need (and huge costs) for permanent DHPG installs in new wells

- Give reliable DHPG simulation in old wells with faulty/non-functioning gauges

- Real-time drawdown management & reservoir monitoring

- Fast simulations for closed loop optimization & reservoir model calibration

- Local flow system modeling at discrete level (multi-segmented approach)

- Minimize need (and huge costs) for multiple field flow meters & maintenance

- Gas lift optimization, slugging flows, ESP PIP modeling, horizontal gas well

liquids loading, plunger lift optimization, critical velocities and lift curves, etc.

Accurate downhole pressure from surface at low cost (THE PRIZE)

Transient real-time modeling for surveillance & optimization

Wellbore and pipeline flow rate calculations (virtual flow metering)

Horizontal well artificial lift simulation for Unconventionals

FOCUS



Complementary points of view of AL Systems

The well is the key component linking the reservoir and the surface in a

hydrocarbon production system. Monitoring its performance and taking action to

keep it operating at optimum condition ensures best production and

financial results. It’s the best lab and infrastructure we can control and measure!

Can I gain knowledge by case

studies or trial-and-error how

different equipment selections and

operating conditions can change

the multiphase flowing mixture

behavior to what I want it to be?

(e.g. to cause liquids lift, lower

FBHP, change flow pattern)

EXTERNAL VIEW (EQUIPMENT) INTERNAL VIEW (MODELS)

Can I better understand via

reliable analytical predictive

modeling how the multiphase

flowing mixture behaves under

different equipment selections and

operating conditions?

(e.g. to mitigate slug flow, to

diagnose liquid loading long before)



How does analytical simulation impact AL in the field?

- Simulate flows in multiple well scenarios (1000’s of wells at a time)

- Suited for IoT, virtual flow metering and real-time fast runs (1GB RAM RPi)

Impact on field-wide production optimization

- Influence of well trajectory on loading behavior, loading/PIP surveillance

- Gas lift optimization, flow conditioning, FTHP-to-FBHP, DHPG simulation

Impact on well operations

- Influence of well trajectory on slugging, holdups, pressure gradients

- Placement of EOT/equipment, lateral length optimization, flow obstructions

Impact on well design



Benchmarking: Simulating Published Lab Data

Cousins, Denton

and Hewitt (1965)

– Exp. # 49, data

also in Table 12.1

of Wallis’s One

Dimensional

Flow textbook



Benchmarking: Simulating Published Lab Data



Benchmarking: Simulating Transient Gas Lift



Big Technology Gaps in Wellbore Simulation

Well “J” Well Case 6



Closing Technology Gaps in Wellbore Simulation



Slightly Up/Down Inclined Flow in Long Laterals

Undulating trajectories will change the phase volume fractions and

velocities behavior (flow patterns) resulting in liquids/gas blocks

Phase volume fractions in slightly up- vs. down-inclined flows are very

different from vertical/deviated flows, i.e. sharp phase holdup

changes

Long laterals is a combination problem, combining always-

developing flow through a segmented/perforated conduit system

and sharp phase holdup changes e.g. liquids held up in up-flow and

gas held up in down-flow



Many Field Observations of Extreme Slip Effects

Source: Eriksen, S., Midttveit, O.: PLT - Overcoming changing multiphase flow behavior along horizontal sections,

http://bergen.spe.no/publish_files/ODS2007_SPE_Eriksen_Hydro.pdf (2010), and at: http://1drv.ms/1DBqiOn



Many Field Observations of Extreme Slip Effects

Baldauff, J., Runge, T., Cadenhead, J., Faur, M., Marcus, R.,

Mas., C., North, R., Oddie, G.: Profiling and quantifying

complex multiphase flow, Schlumberger Oilfield Review,

Autumn (2004)



Big Technology Gaps with Popular Tools!

Simpson, H. C., Rooney, D. H., Grattan, E., Al-Samarrae, F.: Flow pattern and pressure

drop studies, Reports 1, 2 and 3, Research Contract RD/1065/014, Dept. of Mechanical

Engineering, U. of Strathclyde (1976)

Grollman, E., Fortuin, J. M. H.: Transient gas-liquid flow in upward

sloping pipes, approaching the wavy-to-slug flow transition, Trans.

ASME, FED-v. 225, Gas Liquid Flows, pp. 23-30 (1995)

Horizontal, large-diameter

+1 degs from

horizontal



Improved Understanding in Slight up/down Flows:

Blind Test of PipeFractionalFlow against New Data!

Brito, R., Pereyra, E., Sarica, C.: Stratified flow for

downward highly viscous two-phase flow, 8th N.

American Conf. Multiphase Tech., June 20-22, Banff,

Alberta, Canada (2012)

Fig. 8 of reference Fig. 9 of reference

-2 degrees from horizontal



Improved Understanding in Obstructed Flows

Obstructed flows are either fluid

obstructions (cross-jet perforated

pipe flow), or, solid obstructions

(nozzles, chokes, valves, blockages,

bends, branches)

Flow must decelerate and then

accelerate - the convective

acceleration/deceleration pressure

gradient will become the dominant

pressure gradient term if cross-jet

perforated conduit multiphase flows

are considered




Pougatch, K.,

Salcudean, M., Chan, E.,

Knapper, B.: Modeling of

compressible gas-liquid

flow in a convergent-

divergent nozzle, Chem.

Eng. Sci., v. 63, pp. 4176-

4188 (2008)




Same

scale!

Multiple cases in the paper - lines are

our predictions. Demonstrates the

accuracy of our in-situ phase flow rate

calculations.



Case History: Permian Gas-Condensate-Water HW PLT

Flow scanner imager (FSI) prod. log

run on Permian basin gas-condensate-

water well (DEFT and GHOST probes);

simulation starts from surface and all flow

enforced to come only from toe

Validation – simulated severe impact of

well trajectory correlative to data; ALL

phase holdups & pressure predicted

Significance of results – horizontal

wells are uniquely complex systems!

Expected learning – liquids held up in

up-flow and gas held up in down-flow;

demonstrates impact of well trajectory

red = high water holdup

blue = high gas holdup

Unexpected learning – extreme slip

effects exist as long as up-flow and down-

flow exist and NOT on severity of wellbore

trajectory “curviness”; higher likelihood of

terrain-induced slugging



Case History: Permian Gas-Condensate-Water HW PLT



Case History: Permian ESP HW PIP Simulation (2 ways)



Case History: Bakken HEAL System Simulation



Case History: WCSB HEAL System Simulations



Case History: Independent Confirmation of Beneficial

Influence of Back Pressure in Conditioning the Flow

Key Finding: Increasing

backpressure leads to reduced

amplitude of pressure

fluctuations (or reduced

oscillations) and reduced

severe slugging (i.e. higher

frequency, stable slug flow)



Case History: Improved Sand or Solids Erosion

Simulation of Multiphase Flows in Chokes and Valves

Camacho, C. A.: Comparison

of correlations for predicting

pressure losses in high

gas-liquid ratio vertical wells,

M.S. Thesis, U. of Tulsa (1970)



Case History: Improved Sand or Solids Erosion

Simulation of Multiphase Flows in Chokes and Valves



Static Column - Sutton et al. (2003) 2 7/8" Well "11" at 525 Mscf/d - Liquid Loaded

Case History: HW Liquids Loading Simulation



Case History: HW Liquids Loading Simulation

Simulate published loaded

gas well producing under a

static liquid column (SLC)

and compare against the

reported downhole field data

Significance of result: PFF

can simulate liquids loaded

gas well operations including

well death prediction and

changing liquid levels using

only basic field data and

average reservoir pressure

Water holdup red = high blue = low



Static Column - Sutton et al. (2003) 2 7/8" Well "11" at 525 Mscf/d - Liquid Loaded

Case Studies: HW Liquids Loading Simulation

HW Liquids Loading Case Histories using

PFF’s Simple, Analytical Vg,crit Equation (New!)



• Case histories for field-Level

understanding: demonstrate liquid

loading prediction and prevention long

before in horizontal wells; demonstrate

liquid loading effects on major variables

such as WHP, tubing/casing diameters,

fat casing in bend region, small

diameter strings and End-of-Tubing

placement optimization; simulation of

onset of LL for VLP/Lift curves for

quantifying lost liquids production!

• Comprehensive field database:

real horizontal liquid loaded wells in

unconventionals, e.g. Permian, Eagle

Ford, Marcellus, Barnett, lots more...

Permian Case (loading in bend only)



Case History: Permian DHPG Well History Simulation

Fig. 200 of Simulation Workflows (pipefractionalflow.com/userguides): direct comparison of calculated vs. measured

downhole gauge pressures at 9550 ft MD over Permian three-phase horizontal well history (BLIND TEST)

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