1887

Abstract

Summary

Conglomerate reservoir is characterized by high water cut, poor sweep efficiency and inefficient oil recovery during the end-period of water flooding. Surfactant/polymer (SP) flooding has been proved as one of the most promising CEOR methods to improve remaining oil recovery after water flooding, due to the unique synergy of polymer/surfactant. The mechanism and performance of SP flooding in conglomerate reservoir need be studied thoroughly.

We took Karamay oilfield, the biggest conglomerate pilot for SP flooding in China, as an example. Three critical issues, surfactant formulation, relationship between oil displacement and lithology, and filed adjustment methods based on development data, for successful SP flooding in conglomerate were investigated in this paper. Firstly, Petroleum sulfonate surfactant was extracted from Karamay crude oil and three properties including molecular structure and phase behavior were tested to optimize surfactant formations. Then the pore structure difference between conglomerates and sandstones was compared through thin section photographs and mercury-injection capillary pressure tests. Meanwhile, these typical cores of different lithology were used to conduct core flooding experiments, and pore-scale displacement of different concentrations of polymer and surfactant was also evaluated using nuclear magnetic resonance (NMR). After these laboratory researches, a pilot test (18 injection 26 production) at Karamay oilfield was performed in November 2011. Finally, technical issues related to scale-up and unique phenomena of development in conglomerate reservoir were discussed.

The complex of two anionic surfactants made surfactant solution achieve longer range of carbon number distribution, lower CMC and ultra-low interfacial tension with low concentration. Compared with sandstone, the diagenesis of conglomerates normally takes place in a shallower depth and then possesses more tortuous pore structures. Unlike sandstone cores, increasing polymer concentration cannot increase oil efficiency. The result of NMR test showed polymer flooding was hard to mobilize residual oil in pores whose radius was below 5μm. However, residual oil in these pores obviously decreased in SP flooding. For the pilot test, heterogeneous reservoir pressure and very low liquid production were observed in first 2 years. We had to stop some well group tests whose permeability was below 30mD and decrease molecular weight and concentration of polymer to continue testing in those wells (8 injection 13 production) whose permeability is relatively high. It has some good performances including appropriate emulsification, low water cut and high oil recovery (15.5%) until December 2016.

Loading

Article metrics loading...

/content/papers/10.3997/2214-4609.201900085
2019-04-08
2020-03-30
Loading full text...

Full text loading...

References

  1. Demikhova, I.I., Likhanova, N.V., Perez, J.R.H., Falcon, D.A.L., Olivares-Xometl, O., Berthier, A.E.M. and Lijanova, I.V.
    [2016] Emulsion flooding for enhanced oil recovery: filtration model and numerical simulation. Journal of Petroleum Science and Engineering, 143, 235–244.
    [Google Scholar]
  2. Guo, H., Li, Y., Wang, F. and Gu, Y.
    [2018] Comparison of strong-alkali and weak-alkali ASP-flooding field tests in Daqing oilfield. SPE Production & Operations,
    [Google Scholar]
  3. Han, D.K., Yang, C.Z., Zhang, Z.Q., Lou, Z.H. and Chang, Y.I.
    [1999] Recent development of enhanced oil recovery in China. Journal of Petroleum Science and Engineering, 22(1–3), 181–188 .
    [Google Scholar]
  4. Hirasaki, G., Miller, C.A. and Puerto, M.
    [2011] Recent advances in surfactant EOR. SPE Journal, 16(04), 889–907 .
    [Google Scholar]
  5. Hou, Q., Zhu, Y., Luo, Y., Weng, R. and Guoqing, J.
    [2012] Studies on nitrogen foam flooding for conglomerate reservoir. SPE 152010 presented In SPE EOR Conference at Oil and Gas West Asia. Muscat, Oman, 16–18 April
    [Google Scholar]
  6. Khorsandi, S., Qiao, C. and Johns, R.T.
    [2017] Displacement efficiency for low-salinity polymer flooding including wettability alteration. SPE Journal, 22(02), 417–430 .
    [Google Scholar]
  7. Liao, G., Wang, Q., Wang, H., Liu, W. and Wang, Z.
    [2017] Chemical flooding development status and prospect. Acta Petrolei. Sinica, 38(2), 196–207 .
    [Google Scholar]
  8. Liu, S., Miller, C.A., Li, R.F. and Hirasaki, G.
    [2010] Alkaline/surfactant/polymer processes: wide range of conditions for good recovery. SPE Journal, 15(02), 282–293 .
    [Google Scholar]
  9. Liu, Z., Li, Y., Cui, M., Wang, F. and Prasiddhianti, A.G.
    [2016] Pore-scale investigation of residual oil displacement in surfactant–polymer flooding using nuclear magnetic resonance experiments. Petroleum Science, 13(1), 91–99 .
    [Google Scholar]
  10. Liu, Z., Li, Y., Lv, J., Li, B. and Chen, Y.
    [2017] Optimization of polymer flooding design in conglomerate reservoirs. Journal of Petroleum Science and Engineering, 152, 267–274.
    [Google Scholar]
  11. Liu, Z., Cheng, H., Xu, C., Chen, Y., Chen, Y. and Li, Y.
    [2018] Effect of lithology on pore-scale residual oil displacement in chemical flooding using nuclear magnetic resonance experiments. SPE 190450 presented In SPE EOR Conference at Oil and Gas West Asia. Muscat, Oman, 26–28 March.
    [Google Scholar]
  12. Liu, Z., Cheng, H., Li, Y., Li, Y., Chen, X. and Zhuang, Y.
    [2019a] Experimental investigation of synergy of components in surfactant/polymer flooding using three-dimensional core model. Transport in Porous Media, 126(2), 317–335 .
    [Google Scholar]
  13. Liu, Z., Li, Y., Luan, H., Gao, W., Guo, Y. and Chen, Y.
    [2019b] Pore scale and macroscopic visual displacement of oil-in-water emulsions for enhanced oil recovery. Chemical Engineering Science. 197, 404–414.
    [Google Scholar]
  14. Sheng, J.J.
    [2014] A comprehensive review of alkaline–surfactant–polymer (ASP) flooding. Asia -Pacific Journal of Chemical Engineering, 9(4), 471–489 .
    [Google Scholar]
  15. Shiau, B.J.B., Hsu, T.P., Lohateeraparp, P., Rojas, M.R., Budhathoki, M., Raj, A., Wan, W., Bang, S. and Harwell, J.H.
    [2013] Recovery of oil from high salinity reservoir using chemical flooding: from laboratory to field tests. SPE 165251 presented at the SPE Enhanced Oil Recovery Conference. Kuala Lumpur, Malaysia, 2–4 July.
    [Google Scholar]
  16. Wang, H., Cao, X., Zhang, J. and Zhang, A
    [2009] Development and application of dilute surfactant–polymer flooding system for Shengli oilfield. Journal of Petroleum Science and Engineering, 65(1–2), 45–50 .
    [Google Scholar]
  17. Wang, Y., Liu, L., Ji, H., Song, G., Luo, Z., Li, X., Xu, T. and Li, L.
    [2018] Origin and accumulation of crude oils in Triassic reservoirs of Wuerhe-Fengnan area (WFA) in Junggar Basin, NW China: Constraints from molecular and isotopic geochemistry and fluid inclusion analysis. Marine and Petroleum Geology. 96: 71–93.
    [Google Scholar]
  18. Yin, S., Chen, Y. and Wu, X.
    [2018] Different pore structure modalities in sandy conglomerate reservoirs and their forming mechanisms. Arabian Journal of Geosciences, 11(21), 654.
    [Google Scholar]
  19. Zhu, Y., Hou, Q., Liu, W., Ma, D. and Liao, G.Z.
    [2012] Recent progress and effects analysis of ASP flooding field tests. SPE 151285 presented In SPE Improved Oil Recovery Symposium. Tulsa, Oklahoma, USA, 14–18 April.
    [Google Scholar]
http://instance.metastore.ingenta.com/content/papers/10.3997/2214-4609.201900085
Loading
/content/papers/10.3997/2214-4609.201900085
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error