松辽盆地北部大庆长垣浅层气成藏特征分析

近年来，松辽盆地在大庆长垣黑帝庙油层取得了浅层气勘探的新突破，发现了一系列新的气藏。为了认清该区浅层气成藏特征，通过开展精细地质研究并结合组分同位素分析、浅层气成因类型划分图版研究，分析了大庆长垣浅层气藏形成条件、划分了气藏成藏组合、分析了浅层气的成因类型与气藏类型，总结了气藏主控因素。结果表明，大庆长垣浅层气具有较好的形成条件，其环境条件、物质条件均较好；该区浅层气发育有下部、中部和上部3套含气组合，下部含气组合分布在嫩江组二段，为大庆长垣北部主要含气层；中部含气组合分布在嫩江组三段，为大庆长垣南部主要含气层；上部含气组合分布在嫩江组四段，含气程度一般。大庆长垣各地区浅层气成因不同，杏树岗地区与喇嘛甸地区为典型的原油伴生气，来自下伏油藏；葡南地区主要为原油菌解气，重烃组分混入油型气；敖南地区为原油菌解气与油型气的混合气。大庆长垣浅层气气藏类型主要为构造气藏，浅层气成藏主要受原油及气源岩、构造与储层和断裂控制。

Accumulation Characteristics of Shallow Natural Gas in Daqing Placanticline in the Northern Songliao Basin

In recent year,shallow natural gas is making a breakthrough in Heidimiao oil layer in Daqing placanticline in the northern Songliao Basin,and a serious of new natural gas reservoirs were found.In order to obtain the accumulation characteristics of shallow gas,through the study of fine geology,isotopic analysis,genetic types of chart,the formation condition of shallow gas was analyzed and its accumulation combination was determined.In addition,the genetic type and gas reservoir types were analyzed and the main controlling factors of gas reservoir were summarized.Results indicated,formation conditions of shallow gas of Daqing placanticline are good and its environment condition and substance condition are both good.Shallow gas developed three sets of gas combinations,i.e.,the lower,the central and the upper.The lower gas combination is K₁n₂,mainly containing gas to northern placanticline,the central gas combination is K₂n₃ and it isthe main gas bearing layer in the southern placanticline,the upper gas combination is K₂n₄ and the gas level is in general.The contribution factors of shallow gas are different.The Xingshugan and Lamadian area are dominated by typical crude associated gas,coming from next overlying reservoirs.Punan area is characterized by crude oil bacterial degraded gas,Oil-type gas containing heavy hydrocarbon components.In the Aonan area,it is mixed gas of crude oil bacterial degraded gas and oil-type gas.shallow gas reservoir type of Daqing placanticline are structure natural gas reservoir.Shallow natural gas is mainly affected by crude oil and gas source rock,structure,reservoir and fracture.