1.2015 International Perforating Symposium – Europe
IPS-15-33 also SPE 174209 MSThermal Decomposition Effects on Perforating Performance and Safety
A.E. Boock, M.S. Brinsden, Shell
C. Sokolove, T.G. Golian, Hunting Titan
J.L. Maienschein, E.A. Glascoe, Lawrence Livermore National Laboratory
Amsterdam 20th May 2015
2.AFFECTED PERFORATING SYSTEM COMPONENTS
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Perforating Gun
Detonating Cord
Shaped Charge
Arming Sub
Detonator – Det Cord Connection
Perforating Gun
To Top/Well Head
Bottom/Toe
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
3.SETTING THE STAGE…
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155 C downhole temperature
Normal HMX operations
Contingency included severe weather downtime
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
4.ECONOMIC IMPACT
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PROSPER SPOT IPR/VLP simulation results for HMX and HNS charges
Based on time temperature plot provided by manufacturer, HNS was selected over HMX
Result: 30-40% reduction in penetration and an estimated 20% reduction in well performance
180 bbl/day
298 bbl/day
HMX
HNS
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
5.SAFETY
Thermal runaway occurs when heat from thermal decomposition builds within the explosive faster than it dissipates
Once thermal runaway has started, it is often impossible to quench the reaction and prevent an explosion, even if the heat source is removed
The critical temperature at which explosion will occur as well as the time to explosion can be calculated by using:
Explosive Properties
Charge Geometry
Exposure Temperature
Exposure Time
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
6.SAFETY
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Consequence
Increasing Time and Temperature Exposure
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
7.LIMITATIONS OF EXISTING CURVES
Data used to create the industry curves did not identify the explosive type, purity, particle size, binder, pressed density, confinement of the explosive
All of these parameters affect thermal stability
Assumption is that the data originated from results published by national labs
Testing set up and equipment was not specified
The data was extrapolated
Consequences of exceeding the limits are unclear for end users
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
8.THERMAL DECOMPOSITION
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
9.CURRENT METHODS FOR ASSESSMENT - COMPARISON
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15 min
2 hr 45 min
27 hr 45 min
11.5 days (280 hrs)
1.7 min
1 sec
6 hr
Extrapolated
Tested
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
10.Slide 10
CURRENT METHODS FOR ASSESSMENT
Aside from full scale testing, there are three main lab-scale tests used to assess thermal stability:
Vacuum thermal stability (VTS) test
Ampoule test
One Dimensional Time to eXplosion (ODTX)
They measure different phenomena/conditions and their results are not directly interchangeable
They are all safety-derived tests
Major short coming is that the tests don’t reflect the way the explosives are configured in the perforating system because of the free volume in the test set up
Advantage: lab-scale tests can be executed efficiently and affordably
Disadvantage: some tests are so different from the end application that a direct application of the results could result in inaccurate and unsafe guidelines.
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
11.CURRENT METHODS FOR ASSESSMENT - VTS
Vacuum thermal stability (VTS) test:
Has a long history as a thermal stability test for explosives and propellants
The test involves heating a small amount of powder in an evacuated container for many hours
The pressure change is measured and outgassing volume is reported
The underlying assumption is that the outgassing results from decomposition of the explosive
Experimental parameters (mass, temperature, duration) vary significantly among practitioners
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
12.CURRENT METHODS FOR ASSESSMENT - VTS
Chemical Reactivity Test
Related to VTS
Developed at Lawrence Livermore National Laboratory
The quantity and composition of the evolved gases is measured, providing direct measurement of explosive decomposition
Tests are conducted in steel apparatus, thereby avoiding safety problems with pressurized glass
This type of test is best suited as an accelerated aging test to provide experimentalist confidence in the stability of their materials at or near room temperature
The conditions used in these tests are milder than many wells and it may be difficult or impossible to extrapolate results from a 100°C-120°C experiment to higher temperatures
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
13.CURRENT METHODS FOR ASSESSMENT - AMPOULE
Kneisl recently published a new stability test called the Ampoule Test
The test, which is similar to the vacuum thermal stability test, involves heating 1 g of explosive powder in a 10 cm3 glass vial for 2 to 2000 hrs. up to 350°C
The outgassing is measured post-experiment; the experiment can measure up to 300 cm3/g, which is significantly higher than the outgassing from other versions of the VTS test
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This test still measures outgassing from a powder in a vessel with a relatively large amount of headspace
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
14.CURRENT METHODS FOR ASSESSMENT - AMPOULE
The same experiment performed on a high-density pressed part in a vessel with little or no headspace might produce thermal runaway response at lower temperatures or shorter timeframes
This test could be used to develop kinetic models for degradation and outgassing which would be useful in predicting the pressurization as a function of time and temperature
Such a kinetic model would not reliably predict thermal runaway or thermal explosion of a material
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
15.CURRENT METHODS FOR ASSESSMENT - ODTX
One Dimensional Time to eXplosion (ODTX) test
Designed by Lawrence Livermore National Laboratory
In this test, a ½ inch diameter sphere of explosive is heated with an isothermal boundary condition until it explodes
Time to explosion as a function of the boundary temperature is the resulting data
The apparatus consists of two aluminum blocks that each have a ½ inch diameter hemisphere machined out to accommodate the explosive sphere
The anvils are preheated and time-zero is defined as the time when the explosive is inserted between the anvils
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There is no headspace and the anvils are held together with a 15,000 psi load cell which prevents the reaction from quenching early due to gas venting
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
16.CURRENT METHODS FOR ASSESSMENT - ODTX
The test can include a pressure measurement during heating
The results of this test cannot be used to directly predict the response of a large explosive charge because of scalability issues
This test is used to help parameterize or validate a thermal-chemical explosion model
For shaped charges, the thickness of the explosive (approximately ½ inch between the liner and the case) is close to the diameter of the ODTX sphere; consequently it is reasonable to use the results of this test, with simple adjustments to account for the difference in heat transfer through a sphere or a flat slab.
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
17.CURRENT INDUSTRY GUIDENCE
Industry Guidance:
API RP 67 Recommended Practice for Oilfield Safety
API RP 19B Recommended Practices for Evaluation of Well Perforators
Manufacturer supplied time-temperature curves
Neither API RP adequately addresses thermal stability to the extent desired by explosive users within the industry
API RP 19B Section 3 testing does not adequately assess time and performance!
Tests are performed under the same test conditions (i.e. no variation in time or temperature).
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
18.OPPORTUNITIES FOR IMPROVEMENT
The key areas that need to be addressed with respect to thermal stability:
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
19.Slide 19
CONCLUSIONS
IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
20.FORWARD PLAN
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IPS-15-33 • Thermal Decomposition Effects of Perforating and Safety • Mark Brinsden
21.Acknowledgements / Thank You / Questions
Many thanks to Shell, Hunting Titan, and LLNL for support of this work.
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