Jiao Lu, Bo Peng, Mingyuan Li, Meiqin Lin, Zhaoxia Dong and Jiafeng Dong

1. China University of Petroleum, Beijing In-depth Profile Control Property of Pre-crosslinked Polymer Dispersion Jiao Lu, Bo Peng, Mingyuan Li, Meiqin Lin, Zhaoxia Dong and Jiafeng Dong Enhanced Oil Recovering Research Centre, China University of Petroleum, Beijing, China

2. Outline China University of Petroleum, Beijing • Background • Size distribution and microstructure of PCPD • Plugging property / In-depth profile control property of PCPD • Conclusion

3. China University of Petroleum, Beijing Background • Reservoir heterogeneity: the biggest challenge to oil recovery • Application of in-depth profile control agents, can improve amount of oil recoverable by displacement in heterogeneous reservoirs • A new pre-crosslinked polymer dispersion for in-depth profile control was developed in our laboratory

4. China University of Petroleum, Beijing Background Pre-crosslinked polymer dispersion (PCPD): • Prepared by water/water dispersion polymerization • A latex product • The pre-crosslinked polymer coils have excellent plugging performance • We can control the size of the coils by adjusting reaction conditions, crosslinking ratio, and so on

5. Outline China University of Petroleum, Beijing • Background • Size distribution and microstructure of PCPD • Plugging property / In-depth profile control property of PCPD • Conclusion

6. China University of Petroleum, Beijing Size distribution of PCPD Number-size distribution of 50mg/L PCPD Number-size distribution of 50mg/L polymer Dispersion (PD)

7. Microstructure of PCPD China University of Petroleum, Beijing Aggregates of severalpre-crosslinked polymer coils Dried 10mg/L PCPD Magnification: 100 000; scale: 1um

8. Outline China University of Petroleum, Beijing • Background • Size distribution and microstructure of PCPD • Plugging property / In-depth profile control property of PCPD • Conclusion

9. Plugging property of PCPD China University of Petroleum, Beijing Filtrating installation Pressure: 50kPa; pore diameter of membrane: 1.2um (a)100 mg/L PD, 2000mg/L NaCl; (b)100 mg/L PCPD, 2000mg/L NaCl

10. Plugging property of PCPD China University of Petroleum, Beijing r > R R > r >0.46 R r = 0.46 R r < 0.46 R Plugging Mechanism of the membrane filtration The green part is the pore with radius R, the blue part is the particles with radius r

11. Plugging property of PCPD China University of Petroleum, Beijing Nano pre-crosslinked polymer coils Strong plugging property Hydrodynamic diameter Dh Prediction of microstructure of pre-crosslinked polymer coils in extremely dilute aqueous solution

12. Plugging property of PCPD China University of Petroleum, Beijing Effect of concentration on plugging performance (A)50 mg/L; (B) 75 mg/L; (C)100mg/L; (D) 125m g/L; (E) 150mg/L Stability of PCPD Filtration volume vs filtration time 100mg/L PCPD placed under room temperaturewithin 30 days

13. Effect of permeability on in-depth profile control property Concentration: 750 mg/L PCPD , 2000 mg/L NaCl; (a) flow rate: 0.4mL/min; (b) flow rate: 0.8mL/min; China University of Petroleum, Beijing In-depth profile control property of PCPD permeability: 2.25μm2 permeability: 6.04μm2

14. Effect of concentration on in-depth profile control property 2000 mg/L NaCl; flow rate: 0.8mL/min;(a) permeability: 6.04μm2; (b) permeability: 5.50μm2 China University of Petroleum, Beijing In-depth profile control property of PCPD concentration: 750 mg/L PCPD concentration: 1000 mg/L PCPD

15. Conclusion China University of Petroleum, Beijing • PCPD consists of nano crosslinked polymer coils dispersed in aqueous solution media • PCPD has excellent plugging performance, plugging efficiency is enhanced with the increase of concentration of PCPD • PCPD shows high flow resistance and can pass though sandpacks with high permeability

16. Thanks for your attention! China University of Petroleum, Beijing