柴达木盆地西部南翼山浅油藏储层特征

柴达木盆地西部南翼山浅油藏的主要储油层系为新近系上新统下油砂山组(N21)上部及上新统上油砂山组(N22)下部,为背斜构造控制的岩性层状油藏.南翼山浅油藏储层岩性主要包括:(含粉砂)藻灰岩、粉砂质(泥质)泥晶灰岩和灰质(泥质)粉砂岩.各油层一般都包括这3类储层岩性,其中以粉砂质(泥质)泥晶灰岩为主,其次为(含粉砂)藻灰岩和灰质(泥质)粉砂岩.南翼山浅油藏储集空间类型主要包括:溶孔、成岩缝、粒间孔、微孔隙.各油层一般都包括这四类储集空间类型,其中溶孔是最主要的储集空间类型.南翼山浅油藏储层物性最好的为(含粉砂)藻灰岩,其次为粉砂质(泥质)泥晶灰岩和灰质(泥质)粉砂岩.南翼山浅油藏储层的主要控制因素包括:沉积微相、断裂作用、晚期沿断裂带大气淡水的溶解作用、有机酸的溶解作用.

Reservoir characteristics of Nanyishan shallow oil pool in west of Qaidam Basin, China

Neogene (Pliocene) reservoirs in the Nanyishan shallow oil pool in the west of Qaidam Basin are distributed from the upper part of Xiayoushashan Formation (N_2~1) to the lower part of Shangyoushashan Formation (N_2~2). The oil pool is a lithologic layered oil pool controlled by anticline structure. The reservoir rocks in the Nanyishan shallow oil pool mainly include (silty) algal limestone, silty (muddy) micrite (limestone) and limy (muddy) siltstone. Each oil reservoir generally includes these three types of reservoir rocks. Among them, silty (muddy) micrite (limestone) is the most important reservoir rock, and the (silty) algal limestone and limy (muddy) siltstone are second. Reservoir spaces in the Nanyishan shallow oil pool mainly include solution pore, diagenetic fissure, intergranular pore and microporosity. Each oil reservoir generally include these four types of reservoir spaces. Among them, solution pore is the most (important) reservoir space. The best reservoir in the Nanyishan shallow oil pool is (silty) algal limestone, and the second are silty (muddy) micrite limestone and limy (muddy) siltstone. The main controlling (factors) in the Nanyishan shallow oil pool are sedimentation microfacies, rupture action, atmospheric water solution along rupture zones and organic acid solution.