华庆地区长6_3段低渗储层特征及优质储层主控因素

综合运用岩心观察、薄片鉴定、物性分析、压汞分析及试油分析等技术方法,对华庆地区长63段低渗储层特征进行了系统研究,分析了低渗储层的成因,并探讨了优质储层的主控因素。结果表明,华庆地区长63段储层的厚层块状砂岩主要由具有液化流性质的砂质碎屑流沉积形成的相对较厚块状砂岩纵向叠置组成。岩石类型主要为长石砂岩,其次为岩屑长石砂岩;储层具有低孔特低孔-特低渗透超低渗透特征;储集空间主要包括粒间原生孔隙、次生溶蚀孔隙及晶间微孔隙,为小孔微细喉型孔隙结构。杂基含量高、成分成熟度和结构成熟度差是华庆地区长63低渗储层形成的主控因素,压实作用对其形成起到强化作用。沉积鼎盛时期水动力强的主力沉积期次,形成泥质含量较低的砂岩是优质储层形成的主控因素,而较大的储层厚度是优质储层形成的必要条件。

Characteristics of Low Permeability Reservoirs and Main Controlling Factors of High Quality Reservoirs of Chang 63 Member in Huaqing Area

The comprehensive methods , including core observation , thin‐section examination , physical property analysis ,mercury porosimetry ,and oil test ,have been used to systematically study the characteristics of the low permeability reservoirs of Chang 63 Member in Huaqing area ,analyze its origin ,and discuss the main controlling factors of high quality reservoirs .The results show that the thick massive sandstones of the reservoirs of Chang 63 Member in Huaqing area are mainly composed of vertically stacked sandstones that are formed by liquefied sandy clastic flow .The rocks mainly consist of arkose with minor lithic arkose .The reservoirs are characterized by the low to particularly low porosity and permeability .The pores of the reservoir are primarily intergranular pores ,secondary erosion pores , and intercrystalline micropores , the so called micro‐fine throat structures . The formation of low permeability reservoirs of Chang 63 Member in Huaqing area is mainly controlled by the high matrix content ,low textural ,and low compositional maturation ;and it is further strengthened by compaction . Under a suitable water dynamics with low mud content ,a thick sandstones could develop into a high quality reservoir .