overview of proppants and existing standards and · pdf fileoverview of proppants and ....

©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


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


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)


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-2 Proppant properties RP19C 60 (withdrawn)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-5 Long term Conductivity 19D 61(short-term, withdrawn)


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)


Sieve Analysis (Particle Size) ISO 13503-2 §6

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Proppant Size Designation

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20/40

40


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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Presenter

Presentation Notes

Method is fraught with sampling bias


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Photo: Rory Lapka, Montana Tech, 2011


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Proppant shape

Increasing Roundness

Incr

easi

ng S

pher

icity

(from Krumbein/Schloss)


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


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)


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%

Presenter

Presentation Notes

Methods specified by ISO/API are perhaps the most controversial of the suite, but critically important. Geologic closure stresses can easily exceed 10kpsi. Current direction in the API/ISO methods is to ensure a loose pack, with “pluviator”, drop tubes, etc.


Crush Test Apparatus

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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?


Thank you! Questions?

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John Getty, Instructor and Lab Dir Petroleum Engineering Montana Tech, Butte, MT [email protected] 406.496.4846

overview of proppants and existing standards and · pdf fileoverview of proppants and ....

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