潜江凹陷盐间页岩油赋存特征研究

Study on Reserves Characteristics of Intersalt Shale Oil in Qianjiang Depression

利用页岩岩样现场冷冻-密闭碎样-热解含油性评价技术,明确了潜江凹陷盐间页岩油主要赋存在晶间孔和溶孔等无机孔中,游离态油量占总含油量的70%以上。同一层位中不同埋深的油气赋存特征具有随着埋深的增加而游离态油量占总含油量的比例升高、游离态油量中轻烃比例升高的特征。在发育富碳纹层状泥质白云岩、富碳纹层状灰质泥岩、富碳纹层状云质泥岩、钙芒硝充填富碳纹层状云质泥岩四种岩性中,游离态油量以富碳纹层状泥质白云岩最好。

By means of field freezing-enclosed sample pieces-pyrolysis oil bearing evaluation techniques of shale rock samples,it is clear that the intersalt shale oil in Qianjiang Sag mainly occurs in inorganic pores such as intercrystalline and dissolved pores,and the amount of free oil accounts for more than 70%of the total oil content.The characteristics of hydrocarbon occurrence at different buried depths in the same horizon are that the proportion of free oil in total oil content increases with the increase of buried depth and the proportion of light hydrocarbon in free oil content increases.Among the four lithology including carbon-rich striated argillaceous dolomite,carbon-rich striated calcareous clay,carbon-rich striated cloud mass mudstone and carbon-rich striated cloud mass mudstone filled with the glauberite,the best amount of free oil is carbon-rich striated argillaceous dolomite.