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生油岩评价中(Rock-Eval)热成熟参数(T_(max))相对于围岩可能偶而被抑制。普遍认为这是由于沥青对S_2峰的作用,或者由于富硫(和因此产生热不稳定性)干酪根存在的结果。这种现象常常伴随着高自然伽马射线特征及上升的Rock-Eval氢指数(HI)和总有机碳(TOC)含量。这种热成熟度的确定取决于对围岩T_(max)进行内插或直接估算特定样品的抑制范围。如果现有样品仅限于常规或代表有限地层层段的井壁岩心材料,则可能需要直接估算特定样品的抑制范围。艾伯塔盆地的Second White Speckled页岩(白垩系科罗拉多组的一部分)在其部分厚层段显示出T_(max)抑制现象。通过计算在不同热成熟度水平的几口井中作为TOC和HI的线性回归函数的T_(max)值,发现有一定的一致性。在约453℃(晚生油窗)以下,HI每增加50mg HC/g TOC,T_(max)约抑制1℃。因此,通过外推所有的T_(max)值至HI为100～150mg HC/g TOC(Ⅲ型干酪根典型值)的稳定区,可校正Second White Speckled页岩中的T_(max)抑制。
The Rock-Eval thermal maturation parameter (T_ (max)) may be occasionally suppressed relative to the surrounding rock. It is generally accepted that this is due to the effect of bitumen on the S 2 peak or the result of kerogen being rich in sulfur (and therefore thermally unstable). This phenomenon is often accompanied by high natural gamma ray characteristics and increased Rock-Eval hydrogen index (HI) and total organic carbon (TOC) content. This thermal maturity is determined by interpolating the T_ (max) of the surrounding rock or by directly estimating the extent of inhibition of a particular sample. If the existing sample is limited to normal or core borehole material representing a limited interval of layers, it may be necessary to directly estimate the extent of inhibition for a particular sample. The Second White Speckled shale in the Alberta Basin (part of the Cretaceous Colorado Formation) shows a T max suppression at some of its thick intervals. A certain agreement was found by calculating the T max values for the linear regression function of TOC and HI in several wells of different thermal maturities. Below about 453 ° C (late oil window), T max is inhibited by about 1 ° C for every 50 mg HC / g TOC increase in HI. Therefore, T max suppression in Second White Speckled shales can be corrected by extrapolating all T max values to a stable region where HI is 100-150 mg HC / g TOC (Type III kerogen typical).