鄂尔多斯盆地南泥湾超低渗油藏物性及孔隙结构特征

在岩心观察基础上,根据铸体薄片、扫描电镜、压汞等资料,对鄂尔多斯盆地南泥湾超低渗油藏的物性和孔隙结构特征进行了深入研究,并分析了其影响因素.研究结果表明,该区块属于典型的低孔、超低渗油藏,储层以粒间溶孔和残余粒间孔为主,孔隙组合为粒间孔-溶孔和溶孔-粒间孔.孔隙直径小,面孔率低,分布不均匀,平均配位数小于1.5.喉道类型以片状和弯片状为主,多为细孔喉,孔隙间连通性差,存在比较多的无效孔隙.储层岩性细、压实程度高以及重结晶作用是造成孔隙度小,喉道狭窄,渗透率低的主要原因.灰质含量对渗透率的影响也十分明显.研究成果为开发措施的实施提供了依据.

Study on Physical Properties and Pore Structure Characteristics of Nanniwan Ultra-Low Permeability Reservoir in Ordos Basin

On the basis of lithologic observation, according to the casting thin sections, scanning electron microscope and mercury injection data, the physical properties and pore structure characteristics of Nanniwan ultra-low permea- bility reservoir in Ordos Basin are studied in depth, and the influencing factors are analyzed later. Research results showed that the study area was a typical low porosity and ultra - low permeability oil reservoir, intergranular solu- tion pore and intergranular residual pore were the main pore space developed in this reservoir, the pore combination mainly included intergranular pore - dissolution pore and dissolution pore - intergranular pore. The pores have small diameter and are uneven distributed, the surface porosity is low, and the average coordination number is less than 1.5. Laminated shape and curved lamellar throat are the main throat types, the throats are generally fine throats which are uneven distributed. Void pores are well developed there. Fine reservoir lithology, high degree of com- paction and recrystallization are the main reasons for low porosity, narrow throat and low permeability. The gray matter content also influences the permeability obviously. The research results provide the basis for the implementa- tion of development measures.