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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
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 3
FS pump card1 /stroke
FD pump cardQuasi real-time
Norm Distance
Pump card
Confidence level
Down Hole Dynamometer Cards
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 4
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
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 5
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
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 6
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
0.875 60 1500 D Sucker Rods
0.750 47 1175 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
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 8
Base line 1% noise on load
measurement 2% noise on load
measurement
Sticking pump
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 9
1 2 3 4
1 2
3 4
Sticking pump for few
strokes due to a build-up
Acute pump speed change
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 10
32
1
• Pump Speed up : 2 SPM to 10 SPM
1 2 3
Acute pump speed change
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 11
• Pump Slow Down 8 SPM to 2 SPM
• Limited impact on Pump card 32
1
12 3
Sudden pump fillage drop (intake obstruction)
Sept. 29 - 30, 20162016 Sucker Rod Pumping Workshop 12
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. 29 - 30, 20162016 Sucker Rod Pumping Workshop 13
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
The Artificial Lift Research and Development Council and its officers and trustees, and the Sucker Rod Pumping Workshop Steering Committee members, and their supporting organizations and companies (here-in-after referred to as the Sponsoring Organizations), and the author(s) of this Technical Presentation or Continuing Education Training Course and their company(ies), provide this presentation and/or training material at the Sucker Rod Pumping Workshop "as is" without any warranty of any kind, express or implied, as to the accuracy of the information or the products or services referred to by any presenter (in so far as such warranties may be excluded under any relevant law) and these members and their companies will not be liable for unlawful actions and any losses or damage that may result from use of any presentation as a consequence of any inaccuracies in, or any omission from, the information which therein may be contained.
The views, opinions, and conclusions expressed in these presentations and/or training materials are those of the author and not necessarily those of the Sponsoring Organizations. The author is solely responsible for the content of the materials.
The Sponsoring Organizations cannot and do not warrant the accuracy of these documents beyond the source documents, although we do make every attempt to work from authoritative sources. The Sponsoring Organizations provide these presentations and/or training materials as a service. The Sponsoring Organizations make no representations or warranties, express or implied, with respect to the presentations and/or training materials, or any part thereof, including any warrantees of title, non-infringement of copyright or patent rights of others, merchantability, or fitness or suitability for any purpose.