Natco study on new technology in desalters

Advanced Electrostatic Technology for Heavy OilsMay 2009 AGENDA • Opportunity Crude Issues • Electrostatic Technology • Desalting Technology • Dual Frequency® Dehydration • Experience with Heavy Crudes Heavy Crude Issues Difficult-to-Treat Oils The Bad Actors… • Electrical Conductivity • Interfacial Tension • Reverse Emulsions • Limited Differential Density • High Solids • Asphaltenes • Sands. Scale • Crystalline Salts . nS/m Typical High . F Conductivity.Excessive Oil Conductivity 1800 1600 1400 1200 1000 800 600 400 200 0 50 100 150 200 250 300 Temperature. Interfacial Tension Platinum Ring Tensiometer • At Ambient Temperature – 15 -25 dynes/cm • At Treating Temperature – 10 – 15 dynes/cm • With Demulsifier – 7 – 10 dynes/cm • In Electrostatic Field – 3 – 5 dynes/cm . Water-in-Oil Emulsion Typical . Reverse Emulsion 16 API SAGD DilBit . Crystalline Salt A Vexing Problem… Dissolved Salt Na+ H O Cl 2 + + + H2O - Salt Crystals Associated With Brine NaCl Na+ NaCl H2O ClNaCl H2O Dry Salt Crystals NaCl Electrical Forces H2O - . Water-in-Oil Emulsion with Salt Crystal . Crystalline Salt . Electrostatic Technology . Electrostatic Fields Our Choices Include… • • • • • • AC – Conventional & Deep-Field DC (Only with refined products) Dual Polarity® .Combination AC/DC Modulated Dual Polarity® Electro-Dynamic Desalting® Dual Frequency® . 4 weight Reverses 0.Electrostatic Dehydrators Net Drop Forces in Voltage Field Electrode Viscous Drag Volts - + Dipolar Attraction - + Electrophoretic Force Weight Dipole Voltage Field Direction Force Electrophoretic Direction Force Alternating Current Direct Current Oscillates Constant 0.4 weight Constant Net is zero 53 weight . AC/DC Electrostatic Field Dual Polarity® Oil Flux } Dual Polarity® Bulk Water Removal . Desalting Technology . Electrostatic Desalter Single Stage Flow Diagram Oil Outlet Electrostatic Desalter Feedstream to HEX Mixing Valve Water To Disposal Dilution Water Effluent Pump . Electrostatic Desalter Two Stage Flow Diagram Oil Outlet Electrostatic Desalter Feedstream Electrostatic Desalter Mixing Valve Mixing Valve Water To Disposal to HEX Effluent Pump Interstage Recycle Dilution Water Effluent Pump . Electrostatic Desalter Essential Components: 1. Electrostatic Field  Target oil viscosity is 5 to 10 cP 4. Mixing  3 – 6% water up to 15 psi DP 2. Enhanced Distribution / Collection  Maximum vessel utilization . Internal Recycle  From 5 to 10% of crude rate 3. Dual Frequency Dehydration . Oil Conductivity Effects on Voltage Decay Oil Conductivity Low Instantaneous Voltage Medium High Threshold Voltage Voltage . High Oil Conductivity Frequency Effect on Voltage Decay Low Frequency Average Field Strength High Frequency Threshold Voltage Voltage Time Instantaneous Voltage . 40 kV 400 200 0 -200 -400 -600 Time Threshold Voltage 12 .Dual Frequency Waveform Coupled with Voltage Modulation Sinusoidal Wave (or trapezoidal. etc) 600 Primary Voltage. volts Critical Voltage 20 . triangular.25 kV Base Frequency Modulation Frequency Droplet charge follows the Modulation waveform . square. Combined to achieve  Lowest Salt and BS&W . Water Drop Interfacial Tension  Low (pulse) frequency 3.Dual Frequency Dehydrator System Performance: 1. High Conductance Crudes  High (base) frequency 2. Heavy Oil Performance . 5 0.1 0 0 20 40 60 80 100 120 140 160 180 200 220 240 260 280 300 Field AC Dehydrator @ 239 F Modulated Dual Polarity AC Dehydrator @ 219F AC/DC @ 218F Modulated AC/DC @ 220F Bimodal AC/DC @ 220F Oil Flux (bopd/sf) Ref: SPE Paper 97786 .7 Dual Dual Polarity Frequency 0.9 Outlet BS&W (%) Oil API – 21 TAN .2 0.Technology Comparison Pilot Results 1 0.8 0.4 AC Solid Curves Predicted by Electrostatic Dehydrator Computer Model 0.4 0.6 0.3 0. Canada West Sak.2 Flux (BOPD/ft )@ BS&W Comments Diluted SAGD.7 24 90 @ 0.4% 175 @ 0.4% Bohai.4% 208 @ 0.56% 220 @ 0.35% 125 @ 0.Technology Comparison Heavy Oils Pilot / Field Tests Increased Oil Flux 2 Oil Gravity ºAPI 16 20.38% Dual Frequency 125 @ 0.63% 90 @ 0. China Venezuela .4% 20. Alaska Dual Polarity 100 @ 0. 35 0.8 20.3 1.45 1. Dual Frequency Crude Crude API Identification Venezuela Venezuela Wyoming Oklahoma Brazil North Sea 25 17 24 22.1 0. .78 0.8 Feed Temperature Grid Load BS&W (F) (bopd/sf) (%) 150 280 130 135 240 200 9 28 11 11 5 200 94 100 75 80 150 Outlet BS&W (%) Dual Dual Polarity Frequency 1.8 0.5 0.85 0.Advanced Dehydration Results Dual Polarity vs.55 Pilot data on several oils from 13.6 0.27 0.9 0.8 to 25 API.8 13. % Salt.4 0.8 0.16 • Temperature .4 220 6 0.35 6 1 Mixing Efficiency = 25% . AC DF • Wash Water – 5 % • Recycle – 5 % • Valve DP – 10 psi Outlet BS&W. % Salt. ppm Cl5.Heavy Oil Desalting Pilot Results • Dilbit API .70 bopd/ft2 Feed Stage 1 2 Tech. ppm Cl.280 F • Flux .BS&W. 15 0.3 0.5 1 Mix Technology 3 Static + Valve 3 Static + Valve 3 Static + Valve Dynamic Mixing Efficiency = 40% .20 API Average Inlet Salt Is 10 ptb Flux Rate of 115 bpd/sf @ 280 F 5% fresh water Electrostatic Technology Deep-field AC Dual Polarity Dual Frequency Dual Frequency BS&W % 0.Crystalline Salt Removal Aggressive Mixing • • • • WCS Crude .2 1.3 NaCl ptb 2.6 0.4 0. Questions? Heavy Oil Technology for Offshore Applications May 2009 .