根据烃源岩演化过程中残留生烃母质变化原理,建立了 TOC 恢复的数学地质模型,提出了 TOC 演化与各种主控因素之间的定量关系模式,通过对模式中各主控因素在自然条件下变化的特征取值,计算得到了TOC 恢复系数,做出了泥质岩烃源岩和碳酸盐岩烃源岩在含不同类型干酪根情况下的 TOC 演化图版。这一方法的最大特色是避免了人为主观因素和高温压物理模拟实验条件可能带来的结果偏差。研究表明:随着热演化程度的增加,烃源岩内残留的 TOC 含量逐渐减少,在大量生排烃阶段(RO =0.5%~2.0%)变化幅度最大;处于高过成熟阶段(RO >1.2%)的烃源岩,其原始 TOC 恢复系数随 RO 增大而逐渐增加,含Ⅰ型、Ⅱ型、Ⅲ型母质的泥质岩烃源岩 TOC 恢复系数分别可达3.0、2.0、1.4;含Ⅰ型、Ⅱ型、Ⅲ型母质的碳酸盐岩烃源岩 TOC 恢复系数分别可达3.2、2.2、1.5。论文例举了源岩 TOC 恢复在实际工程中的应用。
According to the change of residual hydrocarbon generation materials in the evolution process of source rocks,the geological conceptual model about the TOC recovery was restored,so it pro-posed a quantitative pattern between TOC evolution and the main controlling factors.Then through giving a certain value for each factor that calculated the TOC recovery coefficient,the TOC evolution charts for muddy source rocks and carbonate source rocks in the case of different kerogen types were made.The main characteristic of this method was able to avoid the deviation that subjective factors and physical simulation experiment conditions might lead to.The results were as follows:With the increasing of thermal evolution level,the residual TOC in source rocks reduced gradually in large hydrocarbon expulsion stages (RO =0.5%~2.0%);the reduction amount was biggest for source rocks in high mature-over mature stage (RO〉1.2%);the recovery coefficient gradually increased with the increasing of RO .The TOC recovery coeffi-cients can respectively reached to 3.0,2.0,and 1.4 for muddy source rocks in case of kerogen types Ⅰ,Ⅱ,and Ⅲ;for carbonate source rocks,the TOC recovery coefficients were respectively 3.2,2.2,and 1.5.The practical applications of TOC recovery were exemplified in field.