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Charles Hinrichsen
The document discusses a presentation on controlling scale deposition in oil fields. Primary funding for the Society of Petroleum Engineers Distinguished Lecturer Program comes from member donations and contributions from industry partners. The presentation covers topics like scale types, prediction, inhibition strategies, case studies, and chemical quality control. Preventing scale before it starts to form is emphasized as the most cost-effective approach to dealing with scale formation in oil and gas production.
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Charles Hinrichsen
- 1. Primary funding isprovided by The SPE Foundation through member donations and a contribution from Offshore Europe The Society is grateful to those companies that allow their professionals to serve as lecturers Additional support provided by AIME Society of Petroleum Engineers Distinguished Lecturer Program www.spe.org/dl 1
- 2. Society of PetroleumEngineers Distinguished Lecturer Program www.spe.org/dl 2 Controlling Scale Deposition: Advances in Using Technology to Preserve Production in the Oil Field Charles Hinrichsen Chevron Energy Technology Company (Retired) Houston, Texas USA
- 3. Outline: • Scale: Descriptionand Causes • Scale Inhibition Strategy • Scale Prediction: Scale Tendency and Inhibitor Dosage • Scale Inhibitors: Evaluation and Application • Case Histories • Other Scale Mitigation Methods • Chemical Quality Control • Summary “Imagine an oilfield menace that can smother a productive well within 24 hours. The buildup of scale inside wellbores does exactly that, causing millions of dollars in damage every year!" Crabtree, et. al., “Fighting Scale - Removal and Prevention”, Oilfield Review (Schlumberger), 1999, pp 30 – 45. 3
- 4. What is “Scale”? FexSy CaSO4CaCO3 BaSO4 CaSO4 / CaCO3 CaSO4 4
- 5. Main Scale Types InorganicOrganicGas Naphthenates Hydrates Asphaltenes Waxes Halides Carbonates Sulfates (NORM) Sulfides Oxides / Hydroxides Main Scale Types Scale Types CaCO3 BaSO4 CaSO4 NaCl
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- 7. 7 The Most Cost-Effective Methodfor Dealing with Scale Formation…. PREVENT scale before it starts to form!!
- 8. 8 The Problem WithPredicting Scale: • Thermodynamics: Controls solubility Over- or under-saturated? Scale or no scale? • Kinetics: The rate at which scale forms Even though scale may be thermodynamically favored, it may take a long time to form!
- 9. 9 Scale Formation: Laminar flowTurbulent flow SPE-179863-MS, May 2016. Photos and chart courtesy of BCC Rice University Nucleation Induction time
- 10. 10 Relating Scale Riskto Inhibitor Dosage (ppm) SPE-184518-MS, April 2017; Chart courtesy of BCC Rice University. Production profile
- 11. 11 Abbreviation Chemical Name Hexa-PHexa-phosphonate DETPMP Diethylene-triamine-pentamethylene phosphonate PPCA Polyphospheno-carboxylic acid PVS Polyvinyl sulfonate Vs-Co Vinyl sulfonate co-polymer
- 12. 12 Evaluating Scale InhibitorPerformance Dynamic Flow Loop Testing 0 0.5 1 1.5 0 10 20 30 40 50 60 FlowLoop Pressure(psi) Time (min) 5 mg/L 3 mg/L 1 mg/L
- 13. 13 Scale Inhibition Strategy: •Evaluate Scaling Condition (location and type of scale) • Perform Laboratory Testing • Select Inhibitor Based on Effectiveness, Brine Chemistry, and Temperature • Design a Treatment Plan • Implement in Field
- 14. 14 Application of ScaleInhibitors • Continuous • Squeeze Treatment ► The inhibitor must be present at all times in the water being treated. ► Need to inhibit the growth of SCALE at the source – that is, at the LOCATION where the scale crystals begin to grow and ADHERE to surfaces. ► The inhibitor should be added UPSTREAM of the point where scale deposition starts to occur.
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- 16. 16 Scale Inhibitor Return Volumeof Brine (bbl) BHTMP(mg/l) BHTMP = Bis(HexaMethylene Triamine Penta (Methylene Phosphonic Acid))
- 17. 17 HOWEVER, the actualtreatment may result in an uneven distribution of scale inhibitor because of permeability variations in different zones.
- 18. 18 Squeeze Design: Recommendations Modellingtools may assist with understanding what is best scale management option… calculate chemical requirements for squeeze provide input for an economic model Particularly important in deepwater environments, where intervention may be difficult and expensive But – must be aware of reservoir uncertainties… changes to production schedule, etc. Monitoring is essential.
- 19. 19 Case History: NORM: AUnique Form of Scale It’s radioactive! •First widely acknowledged in 1980s •Radionuclides (natural origin) become concentrated during scale formation •Usually associated with BaSO4 (not CaCO3) •Sulfate scales may contain substituted Ra+2, giving the scale its radioactive character.
- 20. 20 NORM Scale: Safety Concerns:Handling and disposal of radioactive waste require proper training. •Hazards arise primarily from exposure to NORM material in decommissioned equipment: well tubulars, surface piping, vessels, pumps, processing equipment •Inhalation, ingestion, dermal (skin) adsorption •Litigation more expensive than prevention “The trend in upstream environmental litigation is simply that more litigation is on the horizon.”1 SPE 125661, 2010
- 21. 21 Other Scale Mitigation Methods: •Sequestrant Addition (EDTA?) • Dilution (may not be practical) • Temperature and Pressure Control • Control Water Handling Strategy • Acid Addition (used for calcite only) • Ion Exchange Softeners / RO Membranes Scale Removal (if necessary): HCl, Chelants (EDTA), etc.
- 22. 22 Chemical Quality Control •How do I know if the chemical I ordered is the same as what is delivered to the field? • Will the chemical quality / composition remain the same from one shipment to the next?
- 23. 23 Chemical Quality Control Isthe chemical in the field the same as what was purchased? Spectroscopic Fingerprinting: • FT-IR • NMR
- 24. 24 Summary Scale formationcan be a show stopper if not properly managed! Prevent scale BEFORE it starts to form! There are many scale prevention strategies and scale inhibitor chemistries and application techniques that, if properly implemented, can offer a way to economically prevent the loss of production caused by scale formation.
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- 26. Society of PetroleumEngineers Distinguished Lecturer Program www.spe.org/dl 26 Your Feedback is Important Enter your section in the DL Evaluation Contest by completing the evaluation form for this presentation Visit SPE.org/dl #SPEDL