ZHANG Chenglin, YANG Xuefeng, ZHAO Shengxian, et al. Target position optimization for shale reservoirs in Zigong Block of southern Sichuan Basin[J]. Petroleum Reservoir Evaluation and Development, 2022, (3): 496-505. DOI: 10.13809/j.cnki.cn32-1825/te.2022.03.012.
Target position optimization for shale reservoirs in Zigong Block of southern Sichuan Basin
which is located in the southern side of Weiyuan Slope in Sichuan Basin
is a monocline in NW-SE direction. O
3
w
-S
1
l
1-1
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 o
ptimal 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 S
1
l
1-1-1
are the optimal “sweet spots” for both geology and engineering among target layers; ②The production well logging data indicate that
the lower part of S
1
l
1-1-1
shows 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 S
1
l
1-1-1
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.