济阳坳陷石炭-二叠系热演化与生烃阶段

摘要

Based on an analysis of geological structure and sedimentary history, the authors systematically studied the vitrinite prifile of the image well in Jiyang depression, Shengli oilfield. The Late Paleozoic, Mesozoic and Cenozoic paleogeothermal gradients measured by means of regression equations of vitrinite with depth on the basis of thermodynamics are 3.49～3.92 ℃/100m, 4.33～4.67 ℃/100 m and 3.67 ℃/100m respectively. Thermal anomalies of Mesozoic was caused by Yanshanian magmatic underplating. The primary maturities of the Permo-Carboniferouscoal source rocks before uplifting in Indo-sinian movement and Yanshanian movement were R°=0.52%～0.58% and R°=0.90%～1.11% respectively, which correspond to the thresholds of oil generation and the stage of gas generation. Nevertheless, the oil-gas production was damaged by tectonic uplifting and erosion related to Indo-Sinian movement and Yanshanian movement, which is of great significance in correct evaluation of Carboniferous-Permian oil-gas potential in this area.%在对胜利油气区济阳坳陷地质构造和沉积埋藏史分析的基础上，选择典型钻井岩芯，通过系统分析研究其镜质体反射率剖面特征，运用热动力学原理经线性回归确定出本区上古生界、中生界和新生界的古地温梯度，其分别为3.49～3.92 ℃/100m、4.33～4.67 ℃/100m和3.76 ℃/100m。中生代本区出现的高热异常与燕山期岩浆活动板底垫托作用有关。同时确定出印支运动和燕山运动抬升之前，石炭-二叠系烃源岩的成熟度分别为R°=0.52%～0.58%和R°=0.90%～1.11%，它们分别已进入生烃门限和生气阶段，但生烃产物不同程度地遭受构造抬升作用的破坏，这对正确评价本区石炭-二叠系油气资源具有十分重要的意义。