西北中小型盆地油气资源潜力与勘探领域分析

西北中小型盆地众多,分属不同的大地构造单元,具有不同的成盆背景和成烃、成藏条件.存在石炭系、二叠系、侏罗系和白垩系4套主力烃源岩,具有较好的油气勘探前景,但具体到每个盆地又具有一定的差异.笔者在充分收集已有研究成果和跟踪勘探动态及油气新发现的基础上,开展中小型盆地油气资源潜力分析,选取部分中等勘探程度和低勘探程度盆地,分别采用不同的资源量计算方法对盆地或凹陷进行了油气资源预测与计算.认为虽然存在许多制约的难点或瓶颈,但也存在多个油气勘探领域.如侏罗系、白垩系生烃凹陷是油气勘探的有利地区;近源古隆起和山前带是勘探的有利区带;石炭系是潜在的勘探领域;另外,非常规油气资源值得重视.

Hydrocarbon Resource Potential within Middle-and Small-sized Basins and Their Exploration Fields in Northwest China

In vast Northwest China, there are numerous middle-and small-sized basins, which belong to different tectonic units and have different basin-forming backgrounds and reservoir forming conditions. In these middle-and small-sized basins, there are four sets of major hydrocarbon source rocks, namely Carboniferous, Permian, Jurassic and Cretaceous hydrocarbon source rocks, with good prospects for oil and gas exploration. However, every specific basin has a specific condition, which is different from the others. On the basis of the sufficient collection of previous research findings, the tracking of dynamic exploration and new discoveries of hydrocarbon, some typical basins with low-middle exploration degree have been selected as research objects in this paper, the hydrocarbon resource extents of these basins or sags have been evaluated and predicted through utilizing different quantitative calculation methods of resources, and the hydrocarbon resource potential within these middle-and small-sized basins have been analyzed respectively. The results show that, although many difficulties and bottlenecks exist in the works of oil and gas exploration, but there are a number of oil and gas exploration fields. For example, Jurassic and Cretaceous hydrocarbon-generation sags are favorable areas for hydrocarbon exploration. The near-source ancient uplifts and foothill belts are also favorable for oil and gas exploration, while the Carboniferous strata are a potential exploration area. In addition, unconventional hydrocarbon resources shall be worth considering.