准噶尔前陆盆地构造特征与油气勘探方向

准噶尔盆地是陆内坳陷盆地与前陆盆地相叠加的大型复合叠合盆地。自石炭纪以来,经历了3 期伸展及随后的热沉降作用,发育了3 大套烃源岩;其间发育了3 期前陆盆地,形成了一系列构造带,孕育了3 个关键成藏期。多次叠加作用形成了准噶尔盆地西北缘、南缘与东北缘3 个前陆冲断带。西北缘逆掩断裂带早已被证明为大型油气聚集带;南缘冲断褶皱带的大、中型油气田也正被逐个发现;东北缘前陆冲断带也显示出较大的勘探潜力。勘探实践证明,准噶尔盆地前陆冲断带勘探潜力巨大、前景广阔、领域明朗、方向清楚,是准噶尔盆地油气勘探增储上产的重要领域。

The Structural Characteristics and Oil-Gas Explorative Direction in Junggar Foreland Basin

Junggar basin is regarded as a large-scale composite basin superimposed by intracontinental and foreland basins. Since Carboniferous era, it underwent the processes of three-period expanding and thermal subsiding, developing three series of source rocks. In its three-period foreland basins shaped a series of structural belts, developing three vital stages for hydrocarbon accumulation. It was the multi- superimposition that formed such three foreland thrust belts as the northwestern margin, the southern margin and the northeastern margin of Junggar basin, of which the overthrust fault belt in the northwestern margin was already by the proof a large-scale oil-gas accumulation belt; the large- and middle-scale oil-gas fiehts in thrust fold belt of the southern margin are being found one after another, and the foreland thrust belt in the northeastern margin has appeared better and better exploration prospecns. The prospecting practices indicate that this foreland thrust belt in northeastern margin of Junggar basin has a great deal of explorative potentials with obvious realms and clear targets, being an important domain for the incremental reserves and productions in Junggar basin.