黄骅坳陷二氧化碳气成因类型及分布规律

二氧化碳气是经济价值很高且应用前景十分广阔的非烃气体。黄骅坳陷二氧化碳气有多种成因类型,即有机成因、热变质成因和壳 幔混源成因,其中前两种分布较广泛。对于不同成因的二氧化碳气,其分布控制因素有所不同。有机成因二氧化碳气主要分布于生油凹陷周围,是烃类气体的次要伴生产物,并远离大断裂分布。热变质成因二氧化碳气主要分布在深部碳酸盐岩发育、岩浆活动较强烈的地区,并在大断裂附近富集;二氧化碳的含量比有机成因的高,但比壳 幔混源成因的低。壳 幔混源成因二氧化碳气主要出现在深大断裂附近,其分布虽然局限,但纯度是最高的。二氧化碳富集的地区常常是次生溶蚀作用较强的地区,因此也是寻找深部次生优质油气储层的有利地区。

GENETIC TYPES AND DISTRIBUTION OF CARBON DIOXIDE IN THE HUANGHUA DEPRESSION

Carbon dioxide is a nonhydrocarbon gas with high economic value and bright prospects of application. In the Huanghua Depression, there existed various genetic types of carbon dioxide,i.e. organic origin carbon dioxide, thermal metamorphic origin carbon dioxide and crust mantle derived carbon dioxide. The former two types were widely distributed, while the third type occurred locally. The distribution of carbon dioxide of different origin was controlled by different factors. The organic origin carbon dioxide mainly distributed around hydrocarbon generating sags, occurring as a secondary by product of hydrocarbon gas and relatively far away from the main faults. The thermal metamorphic origin carbon dioxide mainly occurred in the region where deep buried carbonates were widely distributed and magmatism was relatively active, and accumulated along the main faults. The crust mantle derived carbon dioxide mainly occurred along large faults. Although distribution of the latter was limited, its concentration was the highest among these three types. Carbon dioxide could greatly enhance the dissolution ability of formation water. The areas of carbon dioxide concentrating were commonly ones of deep dissolution, so as to be favorable areas to look for good oil and gas reservoirs.