Xinjiang Petroleum Geology ›› 2021, Vol. 42 ›› Issue (4): 410-417.doi: 10.7657/XJPG20210403

• OIL AND GAS EXPLORATION • Previous Articles     Next Articles

Quantitative Characterization and Classification of Pore Structures in Chang 4+5 Member in Block Hu-154, Ordos Basin

DING Qiang1a(), CHENG Jian1a, YANG Bo1a, JIN Zixin1b, LIU Fei2, ZHAO Ziwen3, YU Jingwei3()   

  1. 1. PetroChina Changqing Oilfield Company, a.The Sixth Oil Production Plant; b.The First Gas Recovery Plant, Xi’an, Shaanxi 710016, China
    2. Chongqing Gas Field, Southwest Oil and Gas Field Company, PetroChina, Chongqing 400700, China
    3. Karamay Campus, China University of Petroleum (Beijing), Karamay, Xinjiang 834000, China
  • Received:2021-03-05 Revised:2021-05-07 Online:2021-08-01 Published:2021-08-09
  • Contact: YU Jingwei E-mail:154890709@qq.com;yyjjww-1985@163.com

Abstract:

In Block Hu-154 of Hujianshan oilfield in the Ordos basin, the reservoirs of Chang 4+5 member in the Triassic Yanchang formation are of low porosity and low permeability, and there are few researches on the pore structures of the reservoirs and detailed quantitative analysis, which may be the cause for the rapid production decline and less waterflooding control in this block. Based on the data of cores, slices, cast thin sections, SEM, high-pressure mercury intrusion and phase permeability experiments, quantitative characterization and classification of the pore structures have been carried out, and the plane distribution of the pore structures has been studied by combining with well logging curves in the study area. The results show that residual intergranular pores and flake-like and curved flake-like throats are dominant in the Chang 4+5 member in the study area. According to the structure, the pores can be divided into three types: (1) Type Ⅰ pores: the fractal dimension is 2.57~2.61, the average displacement pressure is 1.62 MPa and the oil production rate is over 2 t/d; (2) Type Ⅱpores: the fractal dimension is 2.61~2.66, the average displacement pressure is 2.61 MPa and the oil production rate is higher than 1~2 t/d; (3) Type Ⅲ pores: the fractal dimension is 2.66~2.71, the average displacement pressure is 3.52 MPa and the oil production rate is lower than 1 t/d. Reservoirs with Type II and III pores are distributed on a large scale, and the pore structure in the Chang (4+5)2 is better than that in the Chang (4+5)1 in the study area.

Key words: Ordos basin, Hujianshan oilfield, Block Hu-154, Yanchang formation, reservoir, Chang 4+5 member, pore structure, quantitative characterization

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