热解参数 S1的轻烃与重烃校正及其意义--以渤海湾盆地大民屯凹陷E2 s4（2）段为例

摘要

Free hydrocarbon content ( S1 ) is a frequently-used pyrolytic parameter in assessment of shale oil resource. However,light and heavy hydrocarbon losing during the process often yields result on the low side.For heavy hydrocarbon loss,we compared pyrolysed hydrocarbon content ( S2 ) obtained through pyrolytic experiment before and after extraction of samples to estimate the lost heavy hydrocarbon of S1 .For light hydrocarbon loss,we carried out Rock-Eval and PY-GC experiments on immature shale samples and gold tube experiment on crude samples to calculate the ratio of C6-13/C13+in different stages of maturity according to chemical dynamic theory and Easy Ro model,then took this ratio as the ratio of residual C6-13/C13 +in shale,and finally performed correction of light hydrocarbon lose based on S1 obtained after heavy hydrocarbon correction.Using the corrected parameter in assessment of shale oil resource made a great difference.Taking the E2 s4(2) member in Damintun Sag,Bohai Bay Basin as an example,the result is only 22.6 billion tons without correction but 2.86 times higher (64.7 billion tons) after the corrected parameter was used.It is therefore suggested that correction of light and heavy hydrocarbon loss for residual hydrocarbon S1 during assessment of shale oil resources is necessary.%利用热解参数S1（游离烃含量）对页岩油进行资源评价时存在轻烃和重烃损失的现象，导致计算资源量偏小。针对重烃损失，将相同泥页岩样品经抽提前、后热解实验所得的S2（热解含量）进行对比，二者之差即为S1损失的重烃含量。针对轻烃损失，基于未熟泥页岩样品Rock－Eval和PY－GC实验以及对原油进行的金管实验，根据化学动力学原理求取各动力学参数，结合Easy Ro 模型计算出不同成熟度时生成的C6－13与C13＋的比值，将此值作为烃源岩内残留的C6－13与C13＋比值，并在经重烃恢复之后的S1基础上进行轻烃恢复。使用轻烃与重烃恢复前、后的S1作为页岩油资源评价参数，在资源量计算方面差别较大。以渤海湾盆地大民屯凹陷E2 s4（2）段为例，其恢复前资源量为2.26×108 t，恢复后资源量为6.47×108 t，恢复后资源量为恢复前的2.86倍。因此在利用S1对页岩油进行资源评价时，对S1的轻烃和重烃恢复具有重要意义。