含油气盆地致密砂岩类油气藏成因机制与资源潜力

Formation mechanism classification of tight sandstone hydrocarbon reservoirs in petroliferous basin and resources appraisal

通过对典型致密砂岩油气藏的解剖,并结合成藏过程中油气排运时期和储层致密演化时期匹配关系分析,确定含油气盆地深部发育致密常规油气藏、致密深盆油气藏、致密复合油气藏3种不同类型的致密砂岩类油气藏;在此基础上采用理论计算对中国致密砂岩油气资源进行评价。结果表明:沉积盆地内部实际存在的油气资源量比以往认识和评价的结果大很多,目前中浅部见到的和已发现的常规油气资源不到盆地内富集资源总量的25%,大于75%的油气资源富集在孔隙度小于12%、渗透率小于1×10-3μm2的致密砂岩储层内;在致密油气资源中,致密常规油气资源大致超过油气总资源的25%,致密深盆油气资源超过50%;致密油气资源是含油气盆地挖潜勘探和可持续发展的最主要方向。

A comprehensive review on the forming mechanisms of typical tight-sandstone hydrocarbon reservoirs was presen- ted. Based on pattern matching between oil migration period and tight reservoir evolution, typical tight sandstone reservoirs were summarized into three catgories： conventional tight sandstone reservoir, deep basin tight sandstone reservoir and com- posite tight sandstone reservoir. Through theoretical calculation, tight-sandstone hydrocarbon resources in China were reap- praised. The results reveal far more potential hydrocarbon resources than estimated before. The conventional hydrocarbon re- sources discovered so far account for less than 25% of the total basin hydrocarbon resources, while more than 75% of hydro- carbon resources concentrate in tight sandstone reservoirs with low porosity （〈12%） and low permeability （〈10^-3μm2）. In the latter, over 25% of hydrocarbon concentrates in the tight conventional reservoirs, and over 50% in the tight deep-basin reservoirs. It is therefore suggested that tight hydrocarbon reservoirs remain the main focus in the future hydrocarbon explora- tions and sustainable developments.