长岭断陷火山岩气藏勘探潜力

位于松辽盆地中南部的长岭断陷深层火山岩发育，火山岩气藏成藏条件复杂、勘探难度大，对其勘探潜力的分析结论关系到下一步的勘探决策。为此，对该区火山岩气藏储集条件、圈闭条件、烃源潜力以及成藏模式等进行了分析研究。结果认为：长岭断陷火山岩纵向上多期叠置，发育有原生和次生两大类储集空间，形成了随地质演化而逐渐发育的独具特色的火山岩储集体；火山岩体与基底大断裂和围岩在特定的构造背景上相互配置形成了火山岩岩性圈闭、火山岩与构造复合圈闭；深层具有多种烃源条件，为火山岩储集体提供了丰富的烃源；火山岩储层与多套烃源岩交互发育，形成自生自储型和下生上储型成藏组合，生、储条件配置有利，具备形成以火山岩气藏为目标的大中型气田的条件，具有广阔的勘探前景。

AN ANALYSIS OF EXPLORATION POTENTIAL OF VOLCANIC GAS POOLS IN CHANGLING FAULT DEPRESSION

Deep volcanic rocks are well developed in Changling fault depression in the central southern Songliao Basin. The reservoiring conditions of the volcanic gas pool are complex and the exploration is of great difficulty. The results of exploration potential analysis will influence the decision making for exploration in the next step. The reservoir and trap conditions, potentials of source rocks, and reservoiring patterns of the volcanic gas pools in the study area are studied. The following conclusions are obtained. ①Multi stage volcanic rocks with both primary and secondary pores are vertically superimposed in Changling fault depression, and compose unique volcanic reservoirs. ②The spatial combinations of the volcanic rocks with major basement faults and the surrounding rocks in the special tectonic setting lead to the formation of lithologic traps, and volcanic lithologic and structural combination traps. ③The various source rocks in deep of the fault depression provide rich hydrocarbons for the volcanic reservoirs. ④The interbedding of the volcanic reservoirs and source rocks results in the gas pools with hydrocarbons generated by and accumulated in the same strata, and that with hydrocarbons generated by the source rocks below and accumulated in the reservoirs above. The temporal and spatial combinations of the source rocks and reservoirs are favorable for the formation of middle and large gas fields with volcanic pools as the targets.