二连盆地赛汉塔拉凹陷白垩系火山岩储集层特征及分布预测

利用岩心、薄片等多种分析手段,从火山岩岩性、岩相、孔隙类型、储集层非均质性等方面研究二连盆地赛汉塔拉凹陷白垩系火山岩储集层特征,分析火山岩储集空间类型、储集层物性等特征。通过建立地质—地震对应关系,运用分频属性反演及地震属性分析法对研究区有利储集层分布进行预测。研究结果表明赛汉塔拉凹陷火山岩主要发育于下白垩统阿尔善组三段,火山岩岩性主要为安山岩,储集空间为气孔、杏仁体内孔、溶蚀孔、收缩缝和构造缝等,孔缝组合类型有孔隙型、裂缝—孔隙型、孔洞—裂缝型和裂缝型;岩相主要发育喷溢相,爆发相和喷发沉积相分布较局限,喷溢相上部亚相储集层物性和含油性最好;有利储集层紧邻扎布断裂分布,纵向上分布在下白垩统阿尔善组三段上部,其中扎布断裂西段上升盘赛60井区的阿三段上部层段火山岩储集层相对较好,勘探潜力大,火山岩油气成藏属于源外大断层输导成藏模式。

Characteristics and distribution prediction of Cretaceous volcanic reservoirs in Saihantala Sag,Erlian Basin

With core, thin slice and other analysis methods, this paper analyzed the characteristics of Cretaceous volcanic reservoirs in the Saihantala Sag of the Erlian Basin from lithology, lithofacies, pore type, reservoir heterogeneity, etc. After establishing the relationship between geology and seismic data, this paper predicted some favorable reservoirs of the study region through seismic inversion and seismic attribute analysis methods such as frequency-divided inversion, correlation length analysis and so on. The results showed that volcanic rocks mainly developed in Member 3 of A'ershan Formation of the Lower Cretaceous in the Saihantala Sag, with andesite as the main lithology. Reservoir space types included pores, apricot kernel inner pores, dissolved pores, shrinkage cracks and structural fractures; pore-fissure associations included pore type, fissure-pore type, fissure and vuggy type, fissure type; eruption facies were widely distributed while explosion and volcanic sedimentary facies distributed limitedly; the upper subfacies of eruption facies had excellent reservoir and oil-bearing property; favorable reservoirs distributed along the Zhabu Fault and the upper part of the Member 3 of the A'ershan Formation of the Lower Cretaceous of Sai-60 well block showed great potential; hydrocarbon accumulation model belonged to the model that faults transported hydrocarbon and reservoirs located outside source rocks.