酒西盆地老君庙构造白杨河组间泉子段储层孔隙结构特征

酒西盆地老君庙构造渐新统白杨河组间泉子段储层具有含水率高、驱油效率低的特点，明确储层孔隙结构特征成为提高油气采收率的关键。综合应用铸体薄片观察、扫描电镜分析、毛管压力测试等方法，对老君庙构造白杨河组间泉子段碎屑岩储层的孔隙结构特征及影响因素进行了研究。结果表明：储层岩性主要为岩屑砂岩和长石岩屑砂岩，具有岩屑含量高、成分成熟度和结构成熟度均低的特征；储集空间以残余粒间孔、粒间溶孔为主；按孔隙结构特征将储层分为4类，其中Ⅰ和Ⅱ类储层物性相对较好，渗透率均大于10 mD，毛管压力曲线有明显平台，偏粗歪度；孔隙结构特征参数中反映孔喉集中程度和粗喉道所占比例的参数与物性有较好的正相关关系；间泉子段L层为碱性成岩环境，粒间有较多的黏土矿物和方解石胶结物，局部胶结作用较弱的井段物性较好，M层酸性成岩环境抑制了胶结作用，使部分原生孔隙得以保存，同时酸性流体的溶蚀作用促进了M层优质储层的形成。研究结果可为油田后期有效开发提供地质依据。

Reservoir pore structures of Jianquanzi member in Laojunmiao structure,Jiuxi Basin

Since the formation of Juanquanzi member in Laojunmiao structure has the features of high water cut and low displacement efficiency,the study of pore structure becomes the key to enhanced oil recovery. A variety of experimental test methods were used to study the pore structure and influencing factors of Paleogene Oligocene clastic reservoir in Juanquanzi member of Baiyanghe Formation,such as casting thin section observation,SEM analysis,capillary pressure testing and so on. The result shows that the reservoir lithologies are mainly lithic sandstone and feldspathic lithic sandstone,with high debris content,low maturity of composition and texture. Reservoir spaces are mainly residual intergranular pores and intergranular dissolved pores. The reservoirs can be divided into four types according to pore structure characteristics,and type Ⅰand type Ⅱhave relatively good reservoir property,with permeability above 10 mD. The capillary curves have significant platforms,and coarse skewness. There is a positive correlation between reservoir properties and the concentration of pore throat and the proportion of rough throat. The layer analysis shows that the layer L was in alkaline diagenetic environment,there were a large amounts of clay minerals and calcite cements contained in intergranular pores,and the well sections with weak cementation have good reservoir properties. The acid diagenetic environment of layer M inhibited the cementation,parts of primary pores were preserved,and the dissolution effect by acidic fluids promoted the formation of high quality reservoirs in M layer. The research results can provide geological basis for later effective exploitation.