华池地区长8_1储层特征及其控制因素

Reservoir Characters and Controlling Factors of Chang 8_1 Member in Huachi Area,Ordos Basin

鄂尔多斯盆地华池地区长8_1储层的勘探和开发,受到其致密的储层物性和复杂的油水聚集特征所制约。依据华池地区的岩心照片、铸体薄片及砂岩样品物性资料,分析了长8_1储层的岩石学特征、孔隙结构特征和物性特征及影响储层物性的控制因素。长8_1储层为低孔低渗储层,砂体结构、成岩作用和填隙物含量对储层物性的影响巨大。块状砂体的物性好于含纹层砂体。压实与胶结作用促进储层致密化,交代和溶解作用有利于改善储层物性。储层孔隙度与绿泥石含量成正比,与铁方解石和水云母含量成反比。储层填隙物含量愈高则渗透率愈低。物性相对较好的储层有利于原油的充注和成藏。

The dense reservoir properties and complex oil and water accumulation characteristics have severely restricted further exploration and development of the Chang 81 reservoir in Huachi area, Ordos Basin. In this paper, based on observations and statistics of a large number of core photographs, cast thin sections and physical properties in the study area, the petrological characteristics, pore structure characteristics, and physical properties are studied. Especially, the study focuses on the controlling factors that affect the physical properties of the reservoir. The results show that the Chang 81 reservoir in the Huachi area is a low - porosity and low - permeability reservoir. The sand body configuration, diagenesis and interstitial matter content have a groat influence on the physical properties of the reservoir. The physical properties of the main body are far better than the flanks of the river; compaction and cementation promote the densification of the reservoir, and metasomatism and dissolution help to improve the reservoir properties. The reservoir porosity is proportional to the chlorite content and inversely proportional to the iron calcite and hydronfica content. The higher the reservoir interstitial content, the lower the permeability. Crude oil is more conducive to filling and accumulation in areas where reservoir properties are relatively good.