| Author's Name: YANG Yuran 1,2 , XU Liang 1,2 , MA Weize 3 , YANG Xue 1,2 , LI Runtong 1,2 , ZHU Yiqing 1,2 ,
WANG Qing 1,2 , LI Yanyou 1,2 , WU Qiuzi 1,2 , HE Liang 1,2 |
| Institution: |
| Abstract: |
| The marine shales of Wujiaping Formation and Dalong Formation in Sichuan Basin have favorable conditions
for shale gas accumulation, making them significant replacement fields for natural gas exploration in the future. However,
due to mixed sedimentation influences, diagenesis and pore evolution vary significantly among different lithofacies. The
lithofacies classification, diagenesis, and microscopic pore structure of Wujiaping Formation and Dalong Formation shales
of Well DY1H in northeast Sichuan Basin are confirmed by useing X-ray diffraction, scanning electron microscopy,
energy spectrum analysis, and thin section observation techniques. We also discuss the coupling relationship between
diagenesis and pore development. The results reveal that four types of shale lithofacies are predominantly present in well
DY1H: siliceous, mixed, calcareous, and clay-rich shales. The siliceous shale has the highest TOC. Part of the quartz in
the siliceous shale comes from the transformation of siliceous organisms in the early diagenesis. This early cementation
enhances the compaction resistance of the reservoir, and the retained micropores can provide space for the migration and
enrichment of organic matter. With the increase of burial depth, a large number of organic pores can be formed under the
thermal evolution of organic matter. Due to their high-quality material foundation and favorable storage conditions,
siliceous shales have become preferred lithofacies within the Wujiaping Formation and Dalong Formation shales in
northeast Sichuan Basin. Finally, a diagenetic pore evolution model is established specifically for these favorable
lithofacies which can serve as a reference for studying pore genesis and reservoir distribution prediction in marine shales. |
| Keywords: diagenesis; reservoir characteristics; pore genesis; shale gas; Wujiaping Formation；Dalong Formation;
northeast Sichuan Basin |
|
投稿时间：
2025-01-02 |
|
