Lubricator Testing Process Improvement
Lion Consulting
Final Report
04/21/2016
Submitted to: Well Master Corporation
Dan Nelson
Address: 400 Corporate Circle, Suite K-M, Golden, CO 80401
Phone: 3039800254
E-mail: [email protected]
Submitted by: “Lion Consulting”
Shifali Bose
Garrett Dunlap
Christopher Matthews
Yifei Wu
Ipek Yalki
Advisor: David Cannon
1
1.0 EXECUTIVE SUMMARY
In order to solve an overly time
consuming lubricator pressure testing
process involving the plunger lift system
at a plant in Colorado, Wellmaster PSU
team proposed to replace a tightening
process by using pullers. This hybrid
approach scored highest in the team
comparison alternatives matrix on the
criteria of expenses, time efficiency and
overall performance. While the company
is small, Well Master's efficient and
durable plunger lift systems prove to be
some of the most useful devices in the oil
industry. However, the process for
manufacturing a plunger lift for action
requires tedious processes-specifically
testing the lubricator.
Figure 1.0. Puller Design
Each lubricator is required to undergo a testing process, which involves manual labor and
high-pressure testing. Since Wellmaster is a privately owned company, their resources are
limited in this testing process and thus the manual testing process is too long (almost an hour per
lubricator). The main objective of this project is to shorten the testing process to about five
minutes. In order to do this, the process of tightening the screws is the first focus, as this
accounts for the majority of the testing process.
Deliverables will include the design for the fabrication of the team’s solution to solve the
process problem. The puller will be used to replace the twenty four bolts that previously sealed
the three flanges on the lubricator under high pressures. The puller design shortened the testing
process from one hour to nineteen minutes.
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2.0 TABLE OF CONTENTS
1.0 Executive Summary…………………………………………………………………………………..2
2.0 Table of Contents……………………………………………………………………………………..3
3.0 Table of Figures……………………………………………………………………………………....4
4.0 Introduction and Background…………………………………………………………………………5
5.0 Problem Description…………………………………………………………………………………..5
6.0 Objectives……………………………………………………………………………………………..7
7.0 Methodology…………………………………………………………………………………………..7
8.0 Design Description……………………………………………………………………………………8
9.0 Results………………………………………………………………………………………………...9
9.1 Puller Design…………………………………………………………………………………9
9.2 Material Research……………………………………………………………………………11
9.3 O-ring Design……………………………………………………………………………......12
9.4 Time Study…………………………………………………………………………………..13
9.5 Cost Analysis………………………………………………………………………………..14
9.6 Lubricator Clamp…………………………………………………………………………....16
10.0 Discussion…………………………………………………………………………………………..17
10.1 Puller Design……………………………………………………………………………….17
10.2 Material Research……………………………………………………………………….....19
10.3 O-ring Design…………………………………………………………………………..….20
10.4 Time Study…………………………………………………………………………………20
10.5 Cost Analysis………………………………………………………………………………20
10.6 Lubricator Clamp…………………………………………………………………………..21
11.0 Conclusion and Recommendations………………………………………………………………....21
12.0 References…………………………………………………………………………………………..22
13.0 Appendix…………………………………………………………………………………………....23
3
3.0 TABLE OF FIGURES
Figure 1.0. Puller Design…………………………………………………………………………………2
Figure 5.1.1. Time Study of the Current Process…………………………………………………………6
Figure 9.1.1. Puller Body Front View…………………………………………………………………….9
Figure 9.1.2. Puller Body Top View ……………………………………………………………………..9
Figure 9.1.3. Puller Body Side View …………………………………………………………………….10
Figure 9.1.4. Puller Exploded View……………………………………………………………………...10
Figure 9.1.5 Puller Handle …………………………………………………………………………….....11
Figure 9.2.1 Material Research……………………………………………………………………..…….11
Figure 9.2.2 The Charpy Impact Test………………………………………………………………….....12
Figure 9.3.1 O-Ring Design………………………………………………………………………………12
Figure 9.4.1 Time Study of the New Process…………………………………………………………….13
Figure 9.4.2 Operation Time Bar Chart…………………………………………………………………..13
Figure 9.5.1 US Profit Table……………………………………………………………………………...14
Figure 9.5.2 US Profit Bar Chart…………………………………………………………………….……14
Figure 9.5.3 China Profit Table……………………………………………………………………...……15
Figure 9.5.4 China Profit Bar Chart………………………………………………………………………15
Figure 9.6.1 Lubricator Clamp……………………………………………………………………………16
Figure 10.1.1 Puller Design ………………………………………………………………………………17
Figure 10.1.2 FEA Test 1…………………………………………………………………………………18
Figure 10.1.3 FEA Test 2…………………………………………………………………………………19
Figure A.1 Material Unit Price
………………………………………………………………………………………………….................23
Figure A.2: Drawing of Bolt
…………………………………………………………………………………………………………….25
Figure A.3: Drawing of Arm
…………………………………………………………………………………………………………….25
Figure A.4: Drawing of Hook
…………………………………………………………………………………………………….............26
Figure A.5: Drawing of
Hub………………………………………………………………………………………………………..26
Figure A.6: Drawing of Thread 1(Installed on the hub)
…………………………………………………………….........................................................................27
Figure A.7: Thread 2 (Installed with the Hook)..........................................................................................27
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4.0 INTRODUCTION AND BACKGROUND
Well Master Corporation is a small, privately owned company that manufactures and
markets plunger lift systems and automation equipment to enhance gas well production. Founded
in 1984 in Denver, Colorado, Well Master provides a range of products to provide oil and gas
producers and operators the means to maximize both well efficiency and the well life-span.
Today, the Well Master Viper plunger is recognized industry-wide for its exceptional
performance and durability. While the company has grown significantly over the past three
decades, they remain a company devoted to creating the most innovating plunger lift systems
available (wellmaster.com). Well Master is one of companies owning partnership with Capstone
program and also the sponsor of this special international thesis program.
5.0 PROBLEM DESCRIPTION
Well Master’s supply partners in China produce wellhead equipment called a lubricator.
This particular supplier is located at Changzhou, Jiangsu province, China where many small
manufacturing factories with a good manufacturing flexibility are located; however their
technology and specialty levels are not advanced.
Even though the customers are satisfied with the product, the company would like to
improve the testing process of the lubricator in order to ensure that each lubricator made is tested
properly. Therefore, this project focuses on the creation of test equipment and a process of test
for the in line production inspection testing for a lubricator. Each lubricator is required to
undergo pressure testing at 7500 psi that is a very time consuming and labor-intensive process.
The company believes that the overall preparation time can be reduced with a process that is
quick, easy and robust. The current process requires operators to bolt down the lubricator and
manually plug 5 access ports before the pressure testing can begin. The preparation part of this
process can take in excess of 30 minutes, while the actual test may only take 10 minutes. There
are also potential safety concerns to an operator if steps are missed or not done properly since
pressures are very high.
Severe Condition:
● The lubricator has to undergo pressure testing at 7500
psi whereas the working pressure is approximately 5000
psi in reality.
Current Situation:
● Both time consuming and labor intensive
● The checking process is based on sampling detection
(overall is preferred)
5
●
●
reparation part takes more than 30 minutes
Actual test takes approximately 10 minutes
5.1 Time Study of the Current Process
The time study observation was done for the current testing process is shown below.
Figure 5.1.1
5.2 Current Process Analysis
As mentioned before, in the current process it is required for the operators bolt down the
lubricator and manually plug 5 access ports before the actual pressure testing process begins. The
preparation process is very labor intensive since high pressure is required for the testing which
takes operators to tighten the screws and conduct a pilot test to see if the lubricator is actually
tight or not. If they fail, they need to use more strength to make it tighter.
Currently, they use bolted connection by bolting another flange plate to the flange plate
welded on the other part of the lubricator to seal up the hole in the middle of flange plate. In the
middle, there is a ferrule to seal up the crevice between these two flange plates. The reasons why
it takes so much strength are listed below.
1) Flange plate has 8 bolts and they have to be tightened altogether.
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2) The ferrule currently used is of high hardness. Relative soft material, like rubber is not
strong enough to undergo 7500 psi during the test.
3) After detection, operators have to disassemble 8 bolts, which are tightly connected.
6.0 OBJECTIVES
The main objective of this project is to shorten the pressure testing process of the lubricator by
implementing changes to the design of the testing process. The current testing process runs at a cycle time
of 61.25 minutes, while the end goal cycle time is hoped to be around 20 minutes. The team hopes to
optimize this pressure testing process by implementing a puller design to shorten the setup of the testing
process, which is the longest part of the process. Another objective is to choose an o-ring type and
material that would suit this application at high pressures. Finally, the last objective is to propose the
implementation of a c-type pipe vise in order to smooth the process of applying the puller to the different
size flanges on the lubricator.
7.0 METHODOLOGY
The team used a comparison alternative matrix when deciding which solution would be the most
profitable, time saving, and practical. The idea of using a puller scored highest among all other options.
Using pullers saves Well Master forty minutes every time they pressure test a lubricator. This is a
significant amount of time saved. Solidworks was used to design and test the puller under high pressures
7
reaching the pullers limits at 73,333 psi. A time study was done on the original process concluding that
the pressure test took 61 minutes from start to finish.
8.0 DESIGN DESCRIPTION
After comparing different alternatives in cooperation with SJTU team and our sponsor,
PSU team concluded that the energy-saving tool, which is called puller, is the best solution to
optimize the pressure testing process in a very time efficient manner.
The picture below illustrates the current sealing equipment and the machinery that the
team proposes to use to shorten the time of preparation for the pressure testing process.
Aforementioned diagram under the problem statement reveals that the majority part of
preparation process is tightening the screws that are used to connect the two flanges so the
pressure between those two flanges will be high enough to seal the hole on the flange during the
testing process. Simplifying the sealing process will allow us to decrease the total preparation
time.
Our team proposes to use machinery called puller to replace the extra flanges to seal the
existing flanges. By using a puller those extra three flanges won’t be needed. The puller is a
common tool used in industry to handle situation that needs extreme large forces and high
pressures are involved. Therefore, the team decided that this idea would be very useful to
accomplish our objectives.
With the hook this machinery can easily get connected with the flange and the thread in
the central part can ensure the force we need is large enough to seal the hole of the flange during
the testing process. The puller will drastically eliminate the wasted time during the tightening
process and the cut off time is predicted to be from 61.25 minutes to less than 20 minutes.
8
9.0 RESULTS
9.1 Puller Design
Puller Body Front View
Figure 9.1.1
Puller Body Top View
Figure 9.1.2
9
Puller Body Side View
Figure 9.1.3
The hooks on this puller are interchangeable, this is used to accommodate different sizes of the
flanges that Well Master Corporation used in the lubricator. The material used to build this puller would
be AISI 4304. A detailed material research could be found in section 9.2 and 10.2.
Exploded View
Figure 9.1.4
10
Puller Handle
Figure 9.1.5
9.2 Material Research
Material
Grade
Tensile Strength
Max Yield Strength
Hardness
Alloy Steel
4140
100,000 psi
95,000 psi
22 Max HRC
4340
155,000 psi
116,000 psi min.
37 Max HRC
Figure 9.2.1
Figure 9.2.1 compares the current AISI 4140 to the AISI 4340. The AISI 4340 alloy steel is
comprised of the same material but also includes nickel which contributes to a substantial increase in
hardenability and fracture toughness. When comparing is tensile strength, the 4140 which is 100,000psi is
appreciably lower than the 4340 at 155,000 psi. The same trend follows when comparing yield strength
and hardness as well. Furthermore, the AISI 4340 is much tougher at lower temperatures which is ideal
due to the operating range being between -20 F to 250 F.
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Figure 9.2.2
Figure 9.2.2 compares the Charpy Impact Energy of AISI 4140 and 4340 and shows that at all
temperatures ranging between 0 to 600 C (32 to 1112 F) AISI 4140 has more energy. The Charpy Impact
Test is used to determine the amount of energy absorbed by a material during fracture. The absorbed
energy is a measure of material toughness and is also a tool to study temperature-dependent ductile-brittle
transition.
9.3 O-ring Design
Figure 9.3.1
In Figure 9.3.1 on the left, the horizontal view of the puller is visible while on the right, you can
see a view looking down the flange where the O-ring will be placed. The price of the O-ring is the most
12
important factor in deciding the material of the O-ring, as Well Master preferred the cheapest material
that would sustain the pressure of 7500 psi. Durometer and pressure resistance were also a slight factor.
From the matrix in Figure A.1 in appendix, the nitrile material was ranked the highest. Despite the lowest
pressure resistance characteristic, the price is low enough to bypass this issue, and if necessary, a backup
can be utilized to support the O-ring at high pressure testing.
9.4 Time Study
A time study of the process after the implementation was conducted by our global teammate
Arthur Gao which is shown below.
Figure
9.4.1
A comparison bar chart was made between the results of two time studies that were conducted
before and after the implementation of the new design. As a result, with the implementation of the new
design the operation time was able to reduce from 61.26 min to 19.26 min.
Figure 9.4.2
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9.5 Cost Analysis
Cost analysis of the implementation was done for both USA and China. Overall profit for each
country for 7 years was demonstrated in a table and in a bar chart. The profit calculations can be found
under the Appendix and the procedure for the cost analysis is explained under the discussion part.
As a result from the analysis, both USA and China will be able to make profit after the third year
because that is the year where they pay-off all the money they invested for the implementation and start
making profit by utilizing the new design.
USA
Figure 9.5.1
Figure 9.5.2
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China
Figure 9.5.3
Figure 9.5.4
15
9.6 Lubricator Clamp
Figure 9.6.1
In order to make the process of applying the puller to the flanges, a C-type Pipe Vise from Eagle
Downhole Solutions is recommended. The vises are offered in five different sizes; the 8-½’’ would be the
size for this application, as it works for pipes with O.D. size 1-½’’ to 8-½’’.
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10.0 DISCUSSION
10.1 Puller Design
Figure 10.1.1
As shown in the figure 10.1.1, total weight of the body of the puller would be 39.54 pounds and
the volume is 139.44 cubic inches, which indicates that this puller can be operated by one worker without
any trouble.
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Figure 10.1.2
In order to determine if the puller could be used repeatedly under high testing pressure, 7500 psi,
a simulation is performed. The setup of simulation is as follow, the center internal acme is fixed. A load
of 7853 pound of force is loaded on each of the hooks. The simulation result show that the max stress that
puller would undergo is 71,508.852psi, which is below the max allowable stress 73,333 psi. (110,000/1.5
= 73,333 psi = max allowable stress)
18
Figure 10.1.3
The maximum displacement in the puller is 0.022 inch. This displacement is invisible in daily
life. This simulation results may look a bit scary, but Solidworks has a tendency to exaggerate the
displacement.
Detailed drawings with dimension could be found in the Appendix section.
10.2 Material Research
The Well Master lubricator is composed of AISI 4140 alloy steel that is chromium, molybdenum,
manganese containing low alloy steel. It has high fatigue strength, abrasion and impact resistance,
toughness, and torsional strength. While this material is durable, with the high pressure testing, a stronger
material is preferred. AISI 4340 alloy steel is comprised of the same material but also includes nickel.
The added nickel in AISI 4340 allows it to have more energy as well as a higher tensile strength, yield
strength, and hardness than the AISI 4140. Finally, the higher Charpy Impact of the 4340 at all compared
temperatures shifts the ductile to brittle temperature significantly and allows it to have a higher level of
fracture toughness at lower temperatures while still maintaining hardness at higher temperatures. Unlike
the 4340, the AISI 4140 will distort during heat treatment of higher and thicker sections and will not
quench to the same hardness. Overall, the AISI 4340 is an ideal material for the lubricator due to its
greater hardenability and fracture toughness than that of the AISI 4140.
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10.3 O-Ring Design
The cylinder bore flange has a nominal ID of 2.00”, which is used to decide the Parker No. for the
O-ring design. By using this and a 300 series O-ring, the Parker O-ring 2-326 was selected for this
application. In order to determine material selection, a small matrix was created to decide which can be
found in Figure 9.3.1. The material chosen for the O-ring is Nitrile as it is cheap and durable and able to
withstand pressures of 7500 psi.
10.4 Time Study
The time study was conducted for current testing process and the testing
process after the implementation of the puller. It can be concluded from the time
study results that the time spent for spinning process decreased drastically from
2218 seconds to 260 seconds which had a major impact on the total testing time.
Moreover, it is also apparent that less time is spent for installation and
disconnection after implementing the design. In overall, it is noticeable that a
reduction of 68.57% time took place according to the time study results. To
conclude, the entire process time was reduced from 61.26 minutes to 19.26
minutes.
Before After
10.5 Cost Analysis
In order to see the benefits of the implementation of the new design, a cost analysis for both
countries was necessary. Couple variables were set and objective function for the yearly cost and profit
was made. The variables are listed below.
I: the initial investment,
TCPY: the total cost,
N: the total number of orders per year,
t: the operating time of the testing process with hour as its unit,
n: the number of operating workers,
L: the payment to operating work according to the labor intensity included and with USD/hour as its unit,
U: the utility cost per operating hour,
f: the failed frequency(times per year),
M: the average maintenance cost every time the system failed,
T: the lifespan of the design.
After defining each variable an objective function for the yearly cost was built shown as below.
20
From the calculations, refer to Appendix, the implementation will cost US $7.766.272 during the
first year and $2,766.272 for the following years. For China, the implementation will cost $1,977.344
during the first year and $977,344 for the following years. The reason why the annual costs differ by a
large amount is the fact that initial investment in USA is 5 times greater than in China, the worker wage is
almost 5 times higher in USA than in China and the maintenance cost is also 5 times higher in USA than
in China. These values can be verified by the calculations that are placed in the Appendix
However, in order to see the benefit of implementing such a tool, the team had to see the overall
profit. The profit for each country was calculated by subtracting the yearly cost of the implemented
design by the yearly cost of the current design. As a result, US can make $11,597.63 profit after the 7th
year and China can make $2,628.8 profit. After the 1st year implementation, both countries will be able to
start making profit on the 3rd year. The numbers and calculations are placed under the Appendix and the
tables as well as the graphs are placed under the Results part.
10.6 Lubricator Clamp
When deciding on a clamp for the lubricator, two types of vises were compared: a leaf-chain vise
and a c-type pipe vise. The leaf-chain vise is better for larger equipment, but is harder to use and has a
higher chance of safety issues. Therefore, the c-type pipe vise was chosen. Eagle Downhole Solutions is a
reliable company that manufactures many oilfield type vises, and their c-type vise was chosen as the best
option for a pipe clamp to hold the lubricator while the pullers are applied to the flanges.
11.0 CONCLUSIONS AND RECOMMENDATIONS
In conclusion, in order to reduce the pressure testing time for the lubricator, the team
designed a easy energy saving tool which is called puller. Solidworks was used for the CAD
drawings of the design and FEA test was performed to see if the lubricator can go under pressure
multiple times. Material research was done to see which material would work best for the new
design and AISI 4340 was the best one of all. Next, the team has chosen Parker O-ring 2-326 due to its
cheap price and durability for high pressures. Also, a c-type pipe was chosen for lubricator clamp to hold
the lubricator while the pullers are applied to the flanges. Moreover, the team has been working globally
with the team in China and they performed a time study of both the current process and redesigned
process. According to the results, with the puller, the total testing time was reduced from 61.26 min to
19.6 min. In the end, two cost analyses were done for the implementation in both US and China. As a
result, U.S and China will start making profit from their investment after the 3 year. In overall,
implementing this new design will save the company both time and money.
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12.0 REFERENCES
● "C-Type Pipe Vises." Eagle C-Vises. N.p., n.d. Web. 20 Apr. 2016.
● Parker O-ring Handbook. Lexington, KY: Parker Seal Group, 1982. Web
● Alloy
Steel.
Contalloy,
n.d.
Web.
http://www.contalloy.com/products/grade/l80 .
21
Apr.
2016.
● Charpy Impact. N.p., n.d. Web. 21 Apr. 2016. Path:
http://www.iaa.ncku.edu.tw/~young/chp8%20solu.pdf
● Charpy Graphs. N.p., n.d. Web. 21 Apr. 2016. Path:
https://www.researchgate.net/figure/2 68180964_fig1_Figure-5- Charpy-V-notchedimpact-test-results.
22
Path:
13.0 APPENDIX
Weights:
.5
.1
.4
Material
Price
Durometer
Pressure
Sum Weights
Rank
Polyurethrane
0.33
0.777777778
0.8
0.564444444
3
Nitrile
1
1
0.4
0.76
1
Virgin Teflon
0.2
0.888888889
1
0.588888889
2
Butyl
0.333333
0.777777778
0.8
0.564444444
3
Figure A.1
Values for Variables Used in the Cost Analysis
1. Initial investment will be considered as the tooling and puller itself. We will consider the constraint I
≤ Imax and we will choose the maximum initial investment limit(Imax), which could bring the
minimum annual cost. This limit is roughly $1,000 in China and $5,000 in the US.
2. Even though monthly total number of orders might differ regarding to the demand rate. We will
base our estimation according to the future forecast of the sales. In this case, assuming 12 orders
per month is a good estimation from the future forecast that has been provided from Well Master.
3. Payment to operating workers has a constraint of L ≥ Lmin. We will assume $14 per hour in the
US and $3 per hours in China.
4. The number of workers will be assumed as 2 since the device is so heavy.
5. Utility cost per operating hour will be based on the research. There is an uncertainty for this
variable because utility cost would differ from a busy period to a tranquiliser period. However, for
practical purposes we will use an average number. The number will be assumed to be $81 per
month in US and $50 per month in China.
6. Operating time of the testing process is decreased from 3675 seconds to 1155 seconds
according to the time study results. With the new design, the operating time is 0.321 hours.
7. The failed frequency is an uncertain variable since it is hard to estimate the how many times the device
will fail. However, again for practical purposes we will assume this variable to be 1 time per year.
8. The maintenance cost has the same uncertainty as the failed frequency. When the system fails, the
maintenance cost would refer to either re-purchasing a new device or repairing the broken one. In this
case, the cost would be $500 in the US and $100 in China.
9. The lifespan of the device will be assumed as 7 years based on the research for mechanical systems.
23
24
Drawings of Each Part
Figure A.2: Drawing of Bolt
Figure A.3: Drawing of Arm
25
Figure A.4: Drawing of Hook
Figure A.5: Drawing of Hub
26
Figure A.6: Drawing of Thread 1(Installed on the hub)
Thread 2 (Installed with hook)
27