overview of proppants and existing standards and practices · pdf filemethods specified by...
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©2013 John Getty, Montana Tech 1
ASTM SUBCOMMITTEE D18.26 HYDRAULIC FRACTURING
Tuesday January 29th 2013: 1:00 pm to 5:00 pm
Hyatt Regency Jacksonville Riverfront; Jacksonville, FL
Overview of Proppants and Existing Standards and Practices
John Getty, Instructor and Lab Director Petroleum Engineering, Montana Tech
©2013 John Getty, Montana Tech
Proppant n. Particles used to hold open a fracture induced in an oil and gas reservoir via hydraulic fracturing treatment.
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US Silica 20/40 Ottawa White
Saint-Gobain, 12/18 Interprop Intermediate Strength Ceramic
©2013 John Getty, Montana Tech
Types of proppant
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Three general categories: 1. Natural (sands)
• Northern White (Ottawa) • Brown (Brady)
2. Ceramics (manufactured) • LWC • ISP, HSP (and high density)
3. Other • Light weight polymers
©2013 John Getty, Montana Tech
Darcy-feet
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Anything that negatively impacts fracture conductivity
negatively impacts the economics of the well.
• Density (delivery effects) • Sphericity and roundness • Size and spectral content (viscosity effects) • Resistance to crushing • Fines content (contaminants such as clay) • Resistance to chemical attack • 2nd effects (clean-up, paraffins, resin coated)
©2013 John Getty, Montana Tech
Brief List of Standards
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ISO13503 API RP -1
Viscous properties of completion fluids (“Frac fluid”)
13M
-2 Proppant properties RP19C 60 (withdrawn)
-3 Heavy Brines 13J
-4 Fluid Leak-off 13M-4
-5 Long term Conductivity 19D 61(short-term, withdrawn)
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©2013 John Getty, Montana Tech
Sampling and Sample Handling ISO 13502-2 §4 and §5
• Collection methods • Frequency • Bagging • Splitting • Record keeping
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(ISO 13502-2 §1 thru §3; Scope, Normative References, Abbreviations)
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Sieve Analysis (Particle Size) ISO 13503-2 §6
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Proppant Size Designation
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20/40
40
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Sphericity and Roundness ISO 13503-2 §7
• Examine 20 randomly selected particles • Grade each particle on Roundness • Grade each particle on Sphericity • Find the arithmetic mean for each
characteristic
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Photo: Rory Lapka, Montana Tech, 2011
©2013 John Getty, Montana Tech
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Proppant shape
Increasing Roundness
Incr
easi
ng S
pher
icity
(from Krumbein/Schloss)
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Acid Solubility ISO 13503-2 §8
• Weigh out a 5 gram sample of proppant • Soak the material in a 12:3 mixture of
Hydrochloric (HCl) and Hydroflouric (HF) acids, at 150 °F for 30 minutes.
• Rinse and dry the sample. • Reweigh the sample. • Compute acid solubility,
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1 100treated
untreated
msm
= − ×
s
©2013 John Getty, Montana Tech
Turbidity (Fines and Impurities) ISO 13503-2 §9
• Determines the amount of suspended particles or other finely divided matter.
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Density ISO 13503-2 §10
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• Bulk Density includes both the proppant and the porosity. Measured by filling a known volume with dry proppant and measuring the weight.
• Apparent density excludes extra-granular porosity by placing a known mass in a volume of fluid and determining how much of the fluid is displaced (Archimedes).
• Absolute density is the density the material would have if no intra-granular porosity is present. (e.g. Boyle’s Law porosimetry)
©2013 John Getty, Montana Tech
Bulk Density Apparatus
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Crush resistance ISO 13503-2 §11
• Load a crush cell with (e.g.) 4lb/ft2
• Ramp load to desired stress level • Sieve to determine “fines” produced • If fines are less than 10% by weight, repeat,
increasing loading by 1kpsi. • Crush strength is the highest stress that
produces fines of <10%
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Loading (psi) Fines 4000 2% 5000 6% 6000 15%
©2013 John Getty, Montana Tech
Crush Test Apparatus
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©2013 John Getty, Montana Tech
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The Mysterious “Pluviator” U.S. Patent 7,562,583 B2
• Significant effort has been expended attempting to improve the precision of crush tests.
• Thrust has been to improve consistency of loose-pack.
• Typical variability is 10% to 25%
• Pluviator to be added to impending update to ISO/API?
©2013 John Getty, Montana Tech
Thank you! Questions?
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John Getty, Instructor and Lab Dir Petroleum Engineering Montana Tech, Butte, MT [email protected] 406.496.4846