SPE Technical Meeting and Networking Buffet, Aberdeen 24 th April 2013 Integration of Flow Assurance & Production Chemistry Benefits All: Fact or Fiction? By Colin Smith, Senior Production Chemist Maxoil Solutions Ltd
What is Flow Assurance? • History – Guarantee the Flow / DeepStar Project • Meaning can be broad or narrow – Ensuring successful & economical flow of hydrocarbon streams from reservoir to the point of sale – Multiphase hydrocarbon fluid transportability • Simulation/Modeling of topics such as – Thermo - hydraulic analyses – Operability Characteristics – PVT & Rheology – Slugging / Flow Regime – Fouling / Blockages / Restrictions to Flow – Mechanical Integrity – System performance – reliability / availability – Mitigation, e.g. Hydrate inhibitors
Flow Assurance – Deepwater Projects DeepStar Project Focus
FA Modelling / Simulation Options Flow Assurance Production Chemistry • HYSYS • ScaleChem / Studio Analyser • AspenTech AspenONE • Multiscale / MEGScale • Pro II • ScaleSoftPitzer / OK Scale • PVTSim • Multiflash • Multiflash • dbrSOLIDS • Pipesim • PVTSim & DepoWax • Prosper/GAP • Wax (Msi) • Pipeline Studio • FloWax (Infochem) • OLGA • MWP • PIPEFLO • TUWAX • Flowmaster • OLGA • Cassandra / Norsok • SourSim RL / REVEAL
What is Production Chemistry? Production Chemistry is the management of the chemical properties of fluids that can impact production, product value, asset integrity or environmental/HSE compliance Impact Gas Water Liquid Hydrocarbons Hydrates Emulsions, Scale, Wax, Asphaltenes, Production Sand/fines Naphthenates, Foaming Product Value H 2 S, CO 2 , DMS, Desalination, SRP, BS&W, Sulphur, Mercaptans, Mercury PWRI, Reuse, Mercury, Organic Unconventional chloride Asset Integrity H 2 S, CO 2 , chemicals, Chloride, Bacteria, Organic acids Corrosion Sand, Corrosion Flaring / Emissions Oil in water, WSOs, Oil in water Environmental / Contaminants, Organic Mercury HSE Compliance NORM/LSA Scale
What is Production Chemistry? • Understanding production fluids interactions – Fluids response to changes in P/T/water cut from reservoir to subsea to surface • Risk assessing production problems – Fouling – Physical properties of fluids – Plant integrity related – Environmental / economic • Influencing production system designs & operation • Solving production problems – prevention versus cure – Facilities design – Operational practices – Treatment chemicals (deployment practises)
Production Chemistry & Flow Assurance – A Cross Discipline Network Environmental Well Engineers / Facilities discharges (oil Production Technology Engineers and chemicals) Drilling/Completion HSE Process Design brine chemistry. Technology Dehydration Sampling Initiatives Water Treatment Sample Contamination Chemical Injection Production Chemical Delivery Reservoir CORPORATE Chemistry Commercial Engineers . Contaminants Reservoir Mineralogy Product discount Reservoir Souring PVT Materials & Flow Assurance Corrosion Thermo-Hydraulics OMS Engineers Slugging Risk Management Corrosion Erosion Material Selection VAR Asset Integrity
Flow Assurance & Production Chemistry Quotes ‘ Flow assurance has come to mean the coupling of multiphase flow & production chemistry to manage the interface between the reservoir and topsides processing ’ …… ‘ before, a Flow Assurance evaluation would have discussed hydrates, wax, scale, asphaltenes & corrosion, it now includes network modeling and transient multiphase simulation to determine the operability of the designed facility ’ . Jeff Creek, Senior Flow Assurance Advisor, Chevron (Offshore magazine, 2012). ‘ Flow Assurance is the technical discipline that guarantees achievement of a lifting and transport system ’ s lifetime production targets – from the near wellbore to offloading tanks – by predicting, preventing and solving problems originated by the behaviour of the transported substances (i.e., gases, liquids and solids either separated or in multiphase conditions) ’ . Alberto Di Lullo, Flow Assurance Senior Advisor, Eni E&P
Production Chemistry Issues & Solutions • Wax Chemical Solutions • Asphaltenes • Inhibitors • Dispersants • Inorganic Scales • Dissolvers • Naphthenates / Soaps • Defoamers • Gas Hydrates • Demulsifiers • Sand • Deoilers • Foaming • Scavengers / Biomodifiers • Biocides • Emulsions/Separation/ • DRAs / GTOs Viscosity • Corrosion Mechanical Solutions • Microbiology & Souring Design out / minimise impacts Insulation / DEH • Produced Water / WI Separator sizing / internals • Contaminants Cooling/Heating/Electrostatics • Ice Pigging / Hydrate slurry flow • Chemicals Application CRAs / pipe coatings
FA / PC Issues - 1
FA / PC Issues - 2
Production Chemistry – Where Issues Occur! Contaminants CO 2 Foam CaN Emulsions Hydrates H2S Corrosion Sand Scale Microbiology Asphaltenes Wax
FA & PC During the VAR Process Opportunity Realisation Process. Example case, subsea tieback to existing CPF Appraise Concept Define Execute Operate / Assess Select Fluid sampling, FA Modelling FEED POs Start-up / DST / Downhole Thermo Flowline sizing Commissioning Shutdown / Test Sepr hydraulic Field layout plan Troubleshooting AFEs to POs PVT analysis, Lab analysis. Start up / Operating Optimisation of oil assay, Lab Hydrate curves shutdown procedures operation, experimental Fluids strategies Handover chemicals etc. (wax, asphaltenes, compatibility PEP ownership to emulsions, scaling) BoD asset Formation water FDP, WFSs, Chemical Chemical Chemical composition BfD injection design contract & supply / CRR supply chain logistics Oil & Water CSR, prelim Chemicals Sampling & Demulsifier Geochemistry CRR qualification analysis plan bottle testing Feasibility Mitigation Materials Monitoring prog Confirm oil / report strategies selection CMS water / gas
PC/FA Risk Assessments - Asphaltenes • Laboratory experimental testing (STO / Live oil) – SARA, P Value – Asphaltene Flocculation Point – Live oil ADE / APE – Asphaltene deposition rates • Properties correlations – De Boer plots, Colloidal Instability Index ( CII) • Thermodynamic modelling – Model flocc points / onsets, amounts – Limitations on kinetics, ‘ stickability ’ of asphaltenes, regional asphaltene behaviour • Asphaltene Deposition Simulator (OTC23347, 2012) • Deposition models (tuned) predict where it occurs • Tests/models give risk; actual outcome may be benign!
Reservoir fluid P/T pathway Pressure End of precipitation Asphaltene Bubble point Envelope Precipitation onset Temperature CII = S + As If CII > 1 then risk of precipitation Colloidal R + Ar Instability Index Component (wt%) Oil No. 1 Oil No. 2 Oil No. 3 ( CII ) Predictive (Light) (Intermediate) (Heavy) Tool Saturates 65 44 14 Aromatics 31 40 54 Resins 2.3 9.2 14 Asphaltenes 1.7 6.8 16 CII 2.02 1.03 0.44 Asphaltene Y N N Problems
• Screening Tools : De Boer Plot Allows screening based purely on PVT data � Shows that light, undersaturated oils give the highest asphaltene risk � • Severe Problems • Possible Problems • No Problems • Also an approximate tool, but useful when combined with other screening tests based on SARA analysis
Asphaltene Flocculation Point Test RealView Deposition Cell (Schlumberger)
PC/FA Risk Assessments - Wax • Thermo – Fluid - hydraulic calculations Arrival Temperatures wrt Wax Appearance Temperature (WAT) • Laboratory testing – rheology & wax properties (WAT, viscosity profiles, gelation T/PP, WDT, HTGC, restart P) • Wax modeling – Thermodynamic models – WAT, wax amount – Wax deposition profiles / rate of build up • Experimental data used to tune models • Assess the wax risks – interpretation for solutions • Apply operational experience, use analogues • Wax Management Strategy development
PC/FA Risk Assessments - Hydrates • Assessments dominated by modeling • Lab tests mainly to screen inhibitors (LDHIs) • Thermodynamic model – hydrate curves (Multiflash) • Phase equilibrium prediction program • Degree of subcooling – rate of hydrate formation ▪ Thermodynamic models are used to accurately calculate the hydrate equilibrium and disassociation to within ±1K ▪ This predicts a temperature, at a given pressure, above which hydrates will not form ▪ A nucleation model predicts where hydrates will definitely form ▪ In between the two boundaries is the region of hydrate risk
Hydrates Modelling Typical modelling output showing depression of the hydrate disassociation boundary as greater concentration of methanol is added . Hydrate Curves for Mixes of Injected Seawater and Formation Water
Hydrates Testing Gas Hydrates Flow Loop Plant Commercially Available Autoclave and Rocking Cells (PSL Systemtechnik)
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