基于多元统计方法的油气成藏关键因素筛选与分析——以江陵凹陷新沟嘴组岩性油藏为例

Analysis of main controls of stratigraphic reservoirs in Xingouzui Formation of Jiangling Sag based on a multivariate statistical method

岩性油藏是江汉盆地江陵凹陷未来油气勘探的重要领域,但其成藏控制因素尚未进行系统研究。基于多元统计方法开展了岩性油藏成藏控制因素筛选分析,提出储层条件是江陵凹陷古近系新沟嘴组岩性油藏成藏的关键因素。江陵凹陷新沟嘴组沉积期处于咸化湖盆沉积环境,硬石膏胶结物含量对新沟嘴组岩性油藏砂岩储层致密化起到主要控制作用。其中,硬石膏胶结物含量达7.5%是储层物性的临界值,当含量小于7.5%时物性好,当含量大于7.5%时储层物性变差明显,测井解释偏干。可利用古水深与硬石膏含量的关系,划分有利储层的分布。

Stratigraphic reservoirs are important areas for future oil and gas exploration in the Jiangling Sag of Jianghan Basin,but their hydrocarbon accumulation controls have not been systematically studied.Based on a multivariate statistical method,some key controls of stratigraphic reservoir formation were analyzed.It was proposed that reservoir conditions were the key factors for reservoir formation in stratigraphic reservoirs in the Paleogene Xingouzui Formation in the Jiangling Sag.When the Xingouzui Formation was deposited,the Jiangling Sag was a salt lake basin.The anhydrite cement content played a major role in controlling sandstone densification in stratigraphic reservoirs in the Xingouzui Formation.The anhydrite cement content of 7.5%is a critical value of reservoir physical properties.When the content is less than 7.5%,the physical properties are good.When the content is more than 7.5%,the reservoir physical properties are obviously deteriorated,and the logging interpretation indicates no petroleum resource.The relationship between paleo water depth and anhydrite content can be used to classify the distribution of favorable reservoirs.