Characteristics and determinants of shale reservoirs in the Upper Permian Dalong Formation,Sichuan Basin
Marine black shales are found in the Upper Permian Dalong Formation within the Kaijiang-Liangping trough in the Sichuan Basin.Recently drilling of wells LY1,DY1,and HY1 has revealed high-yield shale gas in this formation,suggesting considerable potential for marine shale gas exploration in the Dalong Formation of the northern Sichuan Basin.Hence,it is highly significant to investigate the characteristics and determinants of shale reservoirs in this formation.In this study,we investigate the organic geochemistry,brittle mineral content,pore types,and pore structures of shales in the Dalong Formation in well DY1,aiming to elucidate the characteristics and determinants of the shale reservoir within.The findings show that the black shales in the Dalong Formation are of deep-water shelf deposits,exhibiting major facies of siliceous and mixed shale,high in brittle mineral contents.The organic matter of these shales exhibits a high abundance,with TOC content averaging at 7.84%,type Ⅱ1-Ⅱ2 kerogens,and high porosities,averaging at 5.78%,and the organic pores act as main storage space with the micro-pores'peak value the highest.The development of pores in the shales is governed by the abundance,type,and thermal maturity of organic matter,while carbonate minerals are detrimental to their growth.
NETL
NSTL
万方数据
