Special Oil & Gas Reservoirs ›› 2022, Vol. 29 ›› Issue (6): 111-118.DOI: 10.3969/j.issn.1006-6535.2022.06.014

• Reservoir Engineering • Previous Articles     Next Articles

Microfracturing-based Expansion Technology and Application in Shallow Ultra-heavy Oil Horizontal Wells

Shen Tingting   

  1. PetroChina Xinjiang Oilfield Company, Karamay, Xinjiang 834000, China
  • Received:2022-02-21 Revised:2022-09-10 Online:2022-12-25 Published:2023-01-10

Abstract: A microfracturing-based expansion technology for horizontal wells was proposed to improve the seepage conditions around the horizontal wellbore, because the infill horizontal wells were not connected to the original wells in composite well pattern under steam flooding and gravity drainage in the heterogeneous reservoirs, Qigu Formation, F Oilfield, Xinjiang Oilfield. The feasibility of microfracturing-based expansion technology and the change characteristics of expanded reservoir were analyzed by laboratory core test, geomechanical finite element simulation and thermal numerical simulation. The results show that he reservoir was high in high quartz while low in clay mineral content, and well developed with pores, which was favorable for water flooding for expansion; in the process of stable pressurization, the spread range of the injection fluid was expanded to reduce the effective confining pressure of the surrounding reservoir and significantly improve the expansion effect; the displacement and porosity of the expanded reservoir in longitudinal direction were obviously better than that in transverse direction, which is conducive to the connection of upper and lower injection-production wells. After five rounds of steam stimulation for preheating after microfracturing-based expansion, the oil wells were connected quickly. In the preheating period, the periodic oil production and oil-steam ratio were significantly improved, and the productivity of horizontal section was greatly enhanced. The study results provide a reference for improving the connectivity among injection and production wells in composite well pattern under steam flooding and gravity drainage.

Key words: Ultra-heavy oil, steam flooding and gravity drainage development, infill horizontal well, microfracturing expansion, reservoir stimulation

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