Oil & Gas Geology ›› 2022, Vol. 43 ›› Issue (5): 1155-1166.doi: 10.11743/ogg20220512

• Petroleum Geology • Previous Articles     Next Articles

Application of backward elimination procedure in evaluation of microscopic reservoir heterogeneity in Chang 6 Member, Ordos Basin

Fanchi Nan1,2(), Liangbiao Lin1,2(), Yu Yu1,2, Zhaobing Chen3,4, Shangchao Mu5, Hongbo Wang6, Guanhua Ji6, Junmin Ma6   

  1. 1.State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation,Chengdu University of Technology,Chengdu,Sichuan 610059,China
    2.Institute of Sedimentary Geology,Chengdu University of Technology,Chengdu Sichuan 610059,China
    3.College of Earth Sciences & Engineering,Xi'an Shiyou University,Xi'an,Shaanxi 710065
    4.Provincial Key Lab of Hydrocarbon Accumulation Geology of Shaanxi,Xi'an,Shaanxi 710065,China
    5.No. 1 Production Plant of Northwest Branch,SINOPEC,Urumqi,Xinjiang 830011,China
    6.No. 2 Gas Production Plant of Changqing Oilfield,PetroChina,Yulin,Shaanxi 719000,China
  • Received:2022-01-20 Revised:2022-07-16 Online:2022-10-01 Published:2022-09-02
  • Contact: Liangbiao Lin E-mail:1625417008@qq.com;linliangbiao08@cdut.cn

Abstract:

The sixth and eighth members of Yanchang Formation (Chang 6 Member in Huaqing area and Chang 8 Member in Heshui area), Ordos Basin, feature complex pore-throat structure and strong micro-heterogeneity under strong diagenetic transformation. The study re-defines evaluation parameters of the microscopic reservoir heterogeneity proposed by predecessors to better quantitatively characterize the microscopic heterogeneity of the reservoir. The backward elimination procedure is adopted to establish a regression equation for the Chang 6 reservoir in Huaqing area using relevant parameters proposed by the predecessors, with N, a parameter for comprehensive evaluation, proposed. Meanwhile, another regression equation is set for the Chang 8 reservoir in Heshui area using the parameters related to high-pressure mercury intrusion, with parameters Gk and Gs proposed, to make quantitative and comprehensive evaluation of the microscopic reservoir heterogeneity while verifying the feasibility of backward elimination in solving geological problems. The results show that parameter N is in good correlation with permeability, and the reservoir can be divided into three sections according to microscopic heterogeneity: strong, medium and weak sections, with correlation coefficients of 0.9812, 0.9496 and 0.7724, respectively. Besides, parameter Gk and porosity, as well as parameter Gs and permeability are also in good correlation. The correlation of the three comprehensive evaluation parameters is significantly higher than that of a single evaluation factor, indicating that backward elimination has achieved relatively ideal results in the quantitative evaluation of microscopic reservoir heterogeneity, and the mathematical method can provide new ideas for solving geological problems related.

Key words: quantitative characterization, microscopic heterogeneity, backward elimination, reservoir quantitative evaluation, Yanchang Formation, Heshui area, Huaqing area, Ordos Basin

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