松辽盆地双坨子气田天然气汞含量特征

 为探讨松辽盆地双坨子气田天然气汞含量分布特征及其成因, 选取该气田7 口气井作为研究对象, 在对采集的天然气进行汞含量检测的同时, 开展天然气组分和烷烃碳同位素分析。检测结果显示, 双坨子气田天然气汞含量介于11~29200 ng/m³之间, 平均为17600 ng/m³, 属于中、低含汞天然气。双坨子气田天然气汞含量随产层深度的增加而增大, 深层天然气要远高于中、浅层天然气, 天然气汞含量的分布特征明显受该盆地双层地质结构的控制。研究表明, 双坨子气田汞含量分布特征既与天然气类型有关, 也与气源岩热演化程度有关。双坨子气田深层天然气为煤型气, 中、浅层气则为油型气或油型气-煤型气的混合气。气源岩热演化程度的不同, 是造成双坨子气田与其邻近的长深气田天然气汞含量差异较大的根本原因。

Analysis of natural gas mercury content characteristics of Shuangtuozi gas field in Songliao Basin

In order to sduty the natural gas mercury content characteristics and its origin in Shuangtuozi gas field, the author carried out natural gas mercury content and alkane carbon isotope analysis of 7 gas wells in the field. The result showed that natural gas mercury content is among 11-29200 ng/m³, and the average value is 17600 ng/m³, which makes it belong to medium and low mercury containing natural gas. The natural gas mercury content increases with the rise of the production depth, and the deep zone has a far greater mercury content than the shallow and middle zones obviously controlled by the basin's double layers structure. Our research showed that the natural gas mercury content is both relevant to the type of the natural gas and the maturity of the source rocks. The type of natural gas from the deep zone is coal type gas and those from the middle and shallow zones are a mixed gas of coal type gas and oil type gas. Different source rocks' thermal evolution levels are the major reason that makes the natural gas mercury content of Shuangtuozi gas field quite different from that of the neighbor Changshen gas field.