1. Comparison of all produced oil samples ANALYSIS OF ASPHALTENES- A MAJOR FACTOR BEHIND EMULSIONS- IN PRODUCED OIL AND SPENT ROCK FOR SAGD AND ES-SAGD Taniya Kar, Matthew Williamson, and Berna Hascakir Petroleum Engineering Department, Texas A&M University STATEMENT OF THE PROBLEM SAGD proved to be efficient for oil sand extraction. ES-SAGD proved to have much less environmental impact, energy consumption, and better recovery than SAGD. Oil-in-water emulsions Water-in-oil emulsions Role of asphaltenes in emulsion formation. Comparison of SAGD and SAGD with solvents in terms of produced emulsions. MATERIALS METHODS AND SAMPLES COLLECTED FROM THE EXPERIMENTS CONDUCTED PREVIOUSLY SAGD & ES-SAGD EXPERIMENTS CONDUCTED PREVIOUSLY - Base SAGD - SAGD with n-hexane - SAGD with co-injection of n- hexane and toluene - Produced Oil - Produced Water - Spent Rock Microscope Contact Angle Zeta Potential FTIR SARA EXPERIMENTAL RESULTS A) PRODUCED OIL ANALYSIS B) SPENT ROCK ANALYSIS Bitumen Characterization Microscopic image Parameter, UnitValue Viscosity @ 23 o C54,000 Gravity, o API @ 23 o C8.65 Asphaltene Content, wt%34.3 Zeta Potential for Asphaltenes of original bitumen, mV -14.0 Contains six vol% water Base SAGD (Sample1) SAGD with nC6 (Sample 2) SAGD with nC6 + tolueneExperimentNames Microscopic Images Water-in-oil emulsion Oil-in-water-in-oil emulsion (triple emulsion) Sample Name Asphaltene Content, wt% Zeta Potential, mV Original Bitumen34.3-14.0 Sample143.91-9.87 Sample224.09-18.77 Sample331.07-16.08 (Sample 3) The greatest asphaltene content was observed for the produced oil sample originated from SAGD (Sample1) O-H stretch prominent for SAGD Base SAGD High amount of asphaltenes More oil-wet asphaltenes (zeta potential value) Detection of water in FTIR spectrum. Both Water-in-oil & oil-in-water-in-oil emulsions SAGD SAGD with nC6SAGD with nC6+toluene Original sample before experiment Intermediate wet 95.27 ̊ 121.44 ̊ More oil-wet Inside SC 113.11 ̊ Intermediate wet Outside SC Original sample before experiment 95.50 ̊ Intermediate wet 107.78 ̊ Intermediate wet 118.11 ̊ More oil-wet Outside SC Inside SC 102.24 ̊ Intermediate wet Original sample before experiment 97.58 ̊ Intermediate wet 117.22 ̊ More oil-wet Outside SC Inside SC Sample Name Asphaltene Content, wt%Residual Oil, wt% Inside Steam Chamber Outside Steam Chamber Inside Steam Chamber Outside Steam Chamber Sample17.914.7822.8318.94 Sample26.17.0116.6917.75 Sample34.873.6513.7314.86 SIGNIFICANCE Base SAGD: High amount and more oil-wet asphaltenes in produced oil → Problems upstream (emulsion, precipitation) High residual oil and asphaltenes on spent rock → Problems downstream (reduced porosity, precipitation) SAGD with solvents promising to reduce the emulsion formation with the generation of more stable asphaltenes. Higher residual oil → higher contact angle (more oil wet nature) clay oil Clay and impurities Original sample before experiment Inside Steam Chamber Outside Steam Chamber clay oil Clay and impurities clay oil Clay and impurities Comparison of all spent rock samples with FTIR Spectrum O-H stretch missing in this region → no significant presence of water in spent rock → supports the oil-wet nature