downhole dynamometer card validation method · downhole dynamometer card validation • pump card...

12th Annual Sucker Rod Pumping

WorkshopRenaissance Hotel

Oklahoma City, Oklahoma

September 27 – 30, 2016

Downhole Dynamometer Card Validation Method

Omar Al Assad, Justin Barton, Kalpesh Singal,

Shyam Sivaramakrishnan

General Electric

Motivation

• Accuracy of pump card estimation is critical for rod pump

control and downhole pump diagnostics

• Using two different approaches to estimate the pump card

offers redundancy that can be used to associate a

confidence level to the obtained pump card

• Pump cards with low confidence level may be used to

trigger alarms for operator to check abnormal system

behavior such as:

1. Noise in load cell measurement

2. Sticking pump

3. Acute pump speed change

4. Sudden pump fillage drop (intake obstruction)

Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 2

(Patent Pending)

Downhole Dynamometer Card Validation

• Pump card validation can be done in real time on

well controller to detect any malfunction or

abnormal operation leading to different pump

card calculation results

• It can be also considered for offline analysis


FS pump card1 /stroke

FD pump cardQuasi real-time

Norm Distance

Pump card

Confidence level

Down Hole Dynamometer Cards


Well

depth

up to

16000

feet

𝜕2𝑢

𝜕𝑡2= 𝑎2

𝜕2𝑢

𝜕𝑥2− 𝑐

𝜕𝑢

𝜕𝑡

𝑎2 =144𝑔𝑐𝐸

𝜌

𝑐 =144𝑐′𝑔𝑐𝜌𝐴

Acoustic velocity

Damping

Sam Gibbs Method - Fourier Series


Time Domain

Surface Data

Fourier coefficients

Wave equation Analytical

solution using Separation

of Variable method for

taper n

Downhole Data

Fourier coefficients

Frequency Domain

Inv. FS

Transform

yes

Last

taper?

n=1

no

n=n+1

Input Tn=output Tn-1

Everitt-Jennings Method – Finite Difference


𝑆𝑢𝑟𝑓𝑎𝑐𝑒

𝑃𝑢𝑚𝑝

• Discretized rod dynamics model:

• Equation recursively solved numerically across all

tapers for 𝑢𝑖+1,𝑗 with surface position and force

measurements as inputs.

𝑁_𝐸𝐿𝐸𝑀𝐸𝑁𝑇𝑆_𝑇𝑂𝑇𝐴𝐿

𝑎21

Δ𝑥 +𝑢𝑖+1,𝑗 − 𝑢𝑖,𝑗

Δ𝑥−

1

Δ𝑥 −𝑢𝑖,𝑗 − 𝑢𝑖−1,𝑗

Δ𝑥

=𝑢𝑖,𝑗+1 − 2𝑢𝑖,𝑗 + 𝑢𝑖,𝑗−1

Δ𝑡 2

− 𝑐𝑢𝑖,𝑗+1 − 𝑢𝑖,𝑗−1

2Δ𝑡

𝑢0,𝑗 = 𝑢𝑝𝑟,𝑚𝑒𝑎𝑠,𝑗

𝑢1,𝑗 =Δ𝑥

𝐸𝐴𝐹𝑝𝑟,𝑚𝑒𝑎𝑠,𝑗 + 𝑢0,𝑗

𝑢𝑝𝑢𝑚𝑝,𝑗 𝑎𝑛𝑑 𝐹𝑝𝑢𝑚𝑝,𝑗

𝑀𝑜𝑑𝑒𝑙 𝐼𝑛𝑝𝑢𝑡𝑠

𝑀𝑜𝑑𝑒𝑙 𝑂𝑢𝑡𝑝𝑢𝑡𝑠

Case Studies

• Test condition

• Solver configuration

• Case Study :

1. Noise in load cell measurement

2. Sticking pump

3. Acute pump speed change

4. Sudden pump fillage drop (intake obstruction)

Lufkin C912-365-168

Stroke 168

Pump 2” @ 4,401 Ft

Motor Nema B, 60 HP

Tubing Anchor 4,052’

Diameter Number Installed

Total

Length Type/Grade

1.500 1 26 Polished Rod

1.000 60 1500 D Sucker Rods



1.625 8 200 Sinker Bars

Total Depth 4401

Fourier Series Finite Difference

Load Fourier coefficients =14

Position Fourier coefficient = 6

Sampling rate: 200 data pt/stroke

Element size ∆x=60’

Sampling time ∆t= 20 ms

Noise in load cell measurement


Base line 1% noise on load

measurement 2% noise on load

measurement

Sticking pump


1 2 3 4

1 2

3 4

Sticking pump for few

strokes due to a build-up

Acute pump speed change


32

1

• Pump Speed up : 2 SPM to 10 SPM

1 2 3

Acute pump speed change


• Pump Slow Down 8 SPM to 2 SPM

• Limited impact on Pump card 32

1

12 3

Sudden pump fillage drop (intake obstruction)


Pump fillage drop from 98%

to 30%

N-1

N+1N

Conclusions and Perspectives

• The ability to calculate pump card using different

methods on well controller offers opportunity for

redundancy to associate a confidence level to the

pump card

• Trigger pump card pattern matching

• This validation approach can be considered for

real-time and offline analysis

• Deployment of this method on well controller will

be considered for future studies on different well

sites to analyze the impact of malfunctions on

pump card estimation


Sept. 27 - 30, 2016 2016 Sucker Rod Pumping Workshop 14

Copyright

Rights to this presentation are owned by the company(ies) and/or author(s) listed on the title page. By submitting this presentation to the Sucker Rod Pumping Workshop, they grant to the Workshop, the Artificial Lift Research and Development Council (ALRDC), and the Southwestern Petroleum Short Course (SWPSC), rights to:

– Display the presentation at the Workshop.

– Place it on the www.alrdc.com web site, with access to the site to be as directed by the Workshop Steering Committee.

– Place it on a CD for distribution and/or sale as directed by the Workshop Steering Committee.

Other use of this presentation is prohibited without the expressed written permission of the author(s). The owner company(ies) and/or author(s) may publish this material in other journals or magazines if they refer to the Sucker Rod Pumping Workshop where it was first presented.

Sept. 27 - 30, 2016 2016 Sucker Rod Pumping Workshop 15

Disclaimer

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downhole dynamometer card validation method · downhole dynamometer card validation • pump card...

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