吐哈盆地中二叠统桃东沟群烃源岩测井评价

Evaluation of Middle Permian source rocks of the Taodonggou Group in the Turpan Hami Basin

为评价吐哈盆地中二叠统烃源岩地球化学特征,在调研现有测井评价方法的基础上,对比现有测井反演烃源岩地球化学方法的预测结果,优选出适合评价吐哈盆地中二叠统烃源岩地化特征的测井技术,进而完成对吐哈盆地中二叠统烃源岩的评价。评价结果显示:在研究区内,多元回归参数法预测总有机碳含量的应用效果远高于ΔlogR模型及其改进型;镜质体反射率(Ro)与深度和声波时差的拟合效果也优于镜质体反射率与深度之间的拟合;利用生烃潜量与有机碳含量建立的模型预测生烃潜量的效果略高于多元回归参数模型。利用上述模型得到的吐哈盆地中二叠统桃东沟群烃源岩总有机碳含量大于1%,生烃潜量PG主要分布范围为2~6mg/g,为较好—好烃源岩,镜质体反射率主要分布范围为0.5%~1.3%,处于低成熟成熟阶段,其中,台南凹陷烃源岩的有机质丰度高于了墩隆起的烃源岩有机丰度。根据该成果以及研究区的实际情况优选出的烃源岩测井评价模型对类似地区的研究具有借鉴意义。

To evaluate the geochemical characteristics of Middle Permian source rocks in the Turpan Hami Basin,this paper explores existing logging technology and compares the prediction results of different geochemical inversion methods.The results show that,in the study area,the multiple regression parameter method is more effective at predicting total organic carbon content(TOC)than theΔlogR model and its improved version,while vitrinite reflectance(Ro)curves including depth and sound wave time difference data are better-fitting than those including only depth.The model based on the direct relationship between hydrocarbon generation potential and TOC is also slightly more accurate than the model based on the multiple regression parameter method.Based on this model,TOC values of the Middle Permian source rocks of the Taodonggou Group in the Turpan Hami Basin are generally higher than 1%,the hydrocarbon generation potential is mainly in the range of 2~6mg/g,representing a good-very good source rock,and the Ro is mainly in the range of 0.5~1.3%in the low-mature-mature stage.Lastly,the organic matter quality of the source rocks in the Tainan Depression is better than that in the Liaodun Uplift.When compared to field observations in the study area,the optimized logging method of evaluating source rocks serves as a point of reference for studying similar areas.