松辽盆地南部深层系天然气成藏规律

松辽盆地南部深层系发育了既相互分割又有成因联系的断陷群,多具有生烃能力。以十屋、长岭断陷为例对松辽盆地南部深层系断陷群的天然气成藏规律进行分析,认为天然气成藏受控于烃源岩的分布与演化、大型构造带与沉积相带的配置关系及保存条件。深层系天然气的两期成藏,分别是登娄库期和嫩江期,晚期成藏是关键。中-高生烃强度区内的大型构造带对油气聚集成藏至关重要。大型构造带内的有利储集体和断裂控制了油气的局部富集;但由于缺乏邻近烃源岩的区域性盖层,保存条件不甚理想。烃源、构造、沉积、保存因素的互相配合可形成多种类型的复式油气聚集带。十屋断陷中央构造、东部秦家屯走滑构造、北部超覆尖灭复式油气聚集带及长岭断陷东部斜坡区东岭复式油气聚集带、中部低隆起复式油气聚集带是勘探的重点目标,长岭断陷西部陡坡区大型水下冲积扇是潜在的复式油气聚集带。

Reservoiring pattern of natural gas in deep of southern Songliao basin

The fault depressions, isolated with one another but genetically related, southern Songliao basin and most of them are considered to be capable of generating are developed in deep of hydrocarbon. An analysis carried out on the reservoiring pattern of natural gas in Shiwu and Changlin fault depressions suggests that the gas reservoiring be controlled by the distribution and evolution of source rocks and the configuration between large-scale structure belt and the sedimentary facies and their preservation conditions. The deep gas reservoirs were formed in two phases , namely Denlouku and Nenjiang, in which the later is more important. Large-scale structure belt in area with medium to high hydrocarbon-generating intensity is critical for the accumulation and reservoiring because the favorable reservoirs and faults inside the belt control the local enrichment of oil and gas. However, the preservation condition is not ideal due to an absence of regional cap adjacent to hydrocarbon source rock. It is concluded that different combinations of source rock, structure, deposition, and preservation, can form various complex hydrocarbon accumulation zones. The central structure, the eastern Qinjiatun strike slip structure and the northern complex hydrocarbon accumulation zone of overlap pinchout type in Shiwu fault depression,and Dongling complex accumulation zone on the eastern slope and the entral low uplift complex accumulation in Changlin fault depression, are the main exploration targets in the future, and the large submarine alluvial fan western steep slope in Changlin fault depression is also regarded as a potential hydrocarbon accumulation zone.