黑龙江省中、新生代残留盆地的天然气前景

GAS PROSPECT OF MESO-CENOZOIC RESIDUAL BASINS IN HEILONGIANG PROVINCE

黑龙江省境内除松辽盆地以外还发育了一系列中、新生代沉积盆地。这些盆地均受深大断裂和基底断裂的控制,多数未见边缘相沉积属残留盆地。盆地内以侏罗系含煤地层为主要目的层,盆地内有含分散有机质的泥岩和煤层两种气源岩,有砂岩和煤层两种储集层,有泥岩和凝灰岩两种盖层,沉积韵律明显,泥岩最大单层厚度不超过50m,有利于烃的一次运移。砂岩与断层发育,有利于烃的再次运移。盆地内逆冲断层发育并伴有线状背斜的良好构造圈闭条件。凝灰岩具膨胀和易分散特性,可以克服断层多保存不利的因素。具备油气藏形成的生、储、盖、圈、运、保六大要素。但盆地面积及盆地内次一级负向构造单元面积均不大,有形成中小型天然气田和小型油田的前景。

<ABSTRACT> Besides Songliao Basin, there are a series of Meso-Cenozoic sedi- mentaty basins in the area of Heilongjiang province, which are controiled by abyssal faults and fundamental faults.Most of them do not have marginal facies dsopsit and belong to residual basins. Jurassic coalbearing stratum within the basin is the objective interval .There are two types of gas source rocks .They arc sholes with scattered organie matter and coal beds, and there are two type of reservoirs, they are sandstone and coal bed, and shale and tulf are the two types of cap rocks.Sedimentary rhythm is clear Naximum thickness of a sirgle shale bed is not more than 50 m, which is suitable for first migration of hydrocarb ons. Sandstones and faults are developed, which is favorable for secondary migra tion of hydrocarbons.Thrust faults are developed within the basins and associated with linear anticline----better structural trap condition. Thus, tuff is charatc-rized by expanding and diffusion and the adverse factor of many faults which are presereved unfavourably could be overcomed.There are the six elements (source, reservoir, cap, cap, migration, and preservation) in these basins.But the area of basins and the areas of secondary negative strutures in these basins are not big enough, so, medium, small gas fields and small oil fields are tended to be formed.