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

3. 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 Background China University of Petroleum, Beijing

4. 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 Background China University of Petroleum, Beijing

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

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

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

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

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

10. China University of Petroleum, Beijing Plugging property of PCPD r > R R > r >0.46 Rr = 0.46 Rr < 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. China University of Petroleum, Beijing Plugging property of PCPD Prediction of microstructure of pre-crosslinked polymer coils in extremely dilute aqueous solution Hydrodynamic diameter D h Nano pre-crosslinked polymer coils Strong plugging property

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 temperature within 30 days

13. In-depth profile control property of PCPD China University of Petroleum, Beijing 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; permeability: 2.25μm 2 permeability: 6.04μm 2

14. Effect of concentration on in-depth profile control property 2000 mg/L NaCl; flow rate: 0.8mL/min; (a) permeability: 6.04μm 2 ; (b) permeability: 5.50μm 2 China University of Petroleum, Beijing In-depth profile control property of PCPD concentration: 750 mg/L PCPDconcentration: 1000 mg/L PCPD

15. Conclusion 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 China University of Petroleum, Beijing

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