Reservoir Evaluation and Development ›› 2022, Vol. 12 ›› Issue (3): 496-505.doi: 10.13809/j.cnki.cn32-1825/te.2022.03.012

• Shale Gas Development • Previous Articles     Next Articles

Target position optimization for shale reservoirs in Zigong Block of southern Sichuan Basin

ZHANG Chenglin1(),YANG Xuefeng1,ZHAO Shengxian1(),ZHANG Jian1,2,DENG Feiyong3,HE Yuanhan1,ZHANG Deliang1,WANG Gaoxiang1,ZHONG Guanghai1   

  1. 1. Shale Gas Institute of PetroChina Southwest Oil & Gasfield Company, Chengdu, Sichuan 610051, China
    2. Shale Gas Evaluation and Exploitation Key Laboratory of Sichuan Province, Chengdu, Sichuan 610213, China
    3. Shunan Gas Field of PetroChina Southwest Oil & Gasfield Company, Luzhou, Sichuan 646000, China
  • Received:2021-08-31 Online:2022-06-26 Published:2022-06-24
  • Contact: ZHAO Shengxian;


Zigong Block, which is located in the southern side of Weiyuan Slope in Sichuan Basin, is a monocline in NW-SE direction. O3w-S1l1-1 is the target layer of that block, which develops black shale with rich organic matters in deep-water continental shelf, while the longitudinal heterogeneity of the reservoir is strong. Different penetration degrees in the sweet spot of horizontal shale well lead to different testing results. In order to determine the longitudinal distribution of the optimal shale target and guide the tracking and adjustment of horizontal well drilling trajectory, based on stratigraphic subdivision, fine evaluation of reservoir is carried out by the comprehensive data of drilling, logging, well testing and laboratory analysis. Meanwhile, the gas production profile data are used to evaluate the impact of the target on shale gas productivity of the horizontal wells. The research results show that: ①Under the influence of both sedimentation and tectonics, the lower part of S1l1-1-1 are the optimal “sweet spots” for both geology and engineering among target layers; ②The production well logging data indicate that, the lower part of S1l1-1-1shows highest gas production contribution of per unit length, which is the optimal target position of the research area; ③The effective fracking length of shale reservoir in the lower part of S1l1-1-1 for horizontal well is the key factor for gas well productivity in Zigong Block. Based on the above results, which supports the productivity evaluation of shale gas effectively, and sets the foundation for realizing large-scale and cost-efficient development of shale gas in that block, the longitudinal distribution thickness of the optimal target in Zigong Block is accurate from 2~5 m to 1~2 m.

Key words: fine evaluation of reservoirs, analysis of gas-production profile, target position optimization, high-quality shale reservoir, Wufeng-Longmaxi Formation

CLC Number: 

  • TE121