烷基二苯并噻吩——烃源岩热演化新指标

ALKYLATED DIBENZOTHIOPHENE INDEX——A NEW METHOD TO ASSESS THERMAL MATURITY OF SOURCE ROCKS

烃源岩热演化程度是判断一个盆地是否具备生油能力的重要指标 ,因此烃源岩的热成熟度是石油工作者研究的重点。二苯并噻吩由于具有对称的分子结构 ,因此具有很宽的热成熟范围 ,而且由于其在各类烃源岩中的广泛分布 ,如果二苯并噻吩系列化合物随热演化变化而发生规律性的变化 ,则其不失为一个良好的成熟度指标。通过对巴彦浩特盆地石炭系的系统取样和分析 ,发现 4,6 -二甲基二苯并噻吩、2 ,4-二甲基二苯并噻吩、1,4-二甲基二苯并噻吩随石炭系埋深增加而规律性变化。初步的研究表明 ,二苯并噻吩系列化合物随热成熟度增高而变化的规律性很强 ,并且与镜质体反射率间存在着良好的线性关系。因此 。

Thermal maturity of source rocks is a focal researched point to petroleum scientists because it is an important index to assess whether source rock of an oil field can generate hydrocarbons.Although researching work of maturity are proceeding on,each maturity parameter has its own deficiency in estimating maturity of source rocks.Dibenzothiophene,researched by organic geochemists,extensively distributes in all sorts of hydrocarbon source rocks and in wide maturity scale because of its symmetric molecular structure.So alkylated dibenzothiophene composition series can be used as efficient maturity indexes if they regularly varies with the change of thermo evolution.By systematically experimenting and analysing Carboniferous rock samples collected from Bayanhaote Basin,this article presents that 4,6 Dimethyl dibenzothiophene,2,4 Dimethyl dibenzothiophene,1,4 Dimethyl dibenzothiophene in aromatic fraction extracted from Carboniferous strata had regularly changes when the depth of the Carboniferous strata increased.The preliminary result shows that variation of concentration of the alkylated dibenzothiophene serial compositions is highly relative to thermal maturity of the strata,and has good linear relationship to vitrinite reflection.Also the result suggests that the alkylated dibenzothiophenes may has optimistic perspective in mature researching work of hydrocarbon source rocks.