The correlation of vitrinite reflectance with maximum temperature in humic organic matter
The correlation of vitrinite reflectance with maximum temperature in humic organic matter
复制标题
DOI：
10.1007/bfb0012103
复制
发表时间：
1986
期刊：
影响因子：
--
通讯作者：
C. E. Barker;M. Pawlewicz
中科院分区：
文献类型：
--
作者：
C. E. Barker;M. Pawlewicz
平均随机镜质组反射率(Rm in%)与最高埋藏温度(Tmax in°C)有很强的相关性(R2=0.7，n>；600)。这些数据由线性回归方程模拟：Tmax和Rm来自35个以上的系统，富含腐殖质有机质，以最大限度地减少化学成分对Rm的影响。热成熟度范围从早期成岩作用到绿片岩变质作用，Tmax间隔约为25-325℃，Rm为0.2-4.0%。埋藏史重建表明，这些系统的功能加热持续时间(在Tmax的15°C范围内随着温度的升高而消逝)从10000年到10m.年以上。Tmax与Rm的强相关性表明，Tmax的增加时间对沉积有机质的热成熟度影响不大，与功能加热时间无关。取而代之的是，井筒温度记录、Tmax测定和Rm测量的校正的不确定性解释了回归分析没有考虑到的大部分剩余的变异性。我们没有尝试将测量的井眼温度修正到平衡的储集层条件，因为对于使用哪种方法没有共识，必要的数据通常没有记录，我们的Tmax-RM校准所做的预测与未校正的Tmax数据进行了比较。我们发现，由于低温系统中岩石上的弱热印记和鲜为人知的埋藏史，在已经冷却的沉积环境中很难确定Tmax。Rm测量的可变性主要是由于操作员或实验室的偏差，双反射比随等级增加，以及成岩历史的变化导致反射抑制。这些研究表明，Tmax控制Rm，使这种关系作为最大地质温度计有用，但几个物理化学和技术因素掩盖了这种相关性。测量Tmax和Rm时出现的问题，表现为明显的数据散布，使得我们的定标不精确。然而，将这种地温计应用于Tmax众所周知的系统表明，它可以产生现实的古温度估计。对变质矿物组合和煤级的研究，以及沉积体系中温度-时间-级别模型的关键测试，证明了对Rm温度控制的其他支持。
Mean random vitrinite reflectance (Rm in %) shows a strong correlation (r2=0.7, n>600) with maximum burial temperature (Tmaxin °C). These data are modelled by the linear regression equation:Tmaxand Rm were compiled from over 35 systems, rich in humic organic matter to minimize the effect of chemical composition on Rm. The thermal maturation data span a range from early diagenesis to greenschist metamorphismover a Tmaxinterval from about 25 – 325° C and 0.2 – 4.0 % Rm. Burial history reconstruction indicates that the functional heating duration (elapsed time as temperature increases within 15° C of Tmax) of these systems ranges from 10,000 yr to more than 10 m.y. The strong correlation of Tmaxwith Rm, irrespective of functional heating duration and in diverse geologic systems, indicates that increasing time at Tmaxhas little influence on thermal maturation of sedimentary organic matter. Instead, uncertainty in correction of borehole temperature logs, Tmaxdetermination, and Rm measurement explains much of the remaining variability not accounted for by the regression analysis. We did not attempt to correct the measured borehole temperature to equilibrium reservoir conditions because there is no consensus on which method to use, the necessary data is often unrecorded, and predictions made from our Tmax— Rm calibration are compared to uncorrected Tmaxdata. We found that Tmaxis difficult to determine in sedimentary environments that have cooled because of the weak thermal imprint on the rocks in low temperature systems and poorly-known burial histories. Variability in Rm measurement appears mainly due to operator or laboratory bias, increasing bireflectance with rank, and variation in diagenetic history which causes reflectance suppression.These studies imply that Tmaxcontrols Rm, making the relationship useful as a maximum geothermometer, but that several physico-chemical and technical factors obscure the correlation. The problems in measuring Tmaxand Rm, shown by the appreciable data scatter, make our calibration imprecise. However, application of this geothermometer to systems where Tmaxis well known shows that it yields realistic paleotemperature estimates. Other support for temperature control of Rm is documented from studies of metamorphic mineral assemblages and coal rank, and critical testing of temperature-time-rank models in sedimentary systems.