鄂尔多斯盆地富县-甘泉地区长6～长9油层组储层特征研究

The Reservoir Characteristics of Chang 6 and Chang 9 Reservoirs in Fuxian-Ganquan Area of Ordos Basin

通过对富县-甘泉地区的长6～长9油层组岩矿特征分析认为,岩石类型主要以细粒的长石砂岩、岩屑长石砂岩为主,含有少量长石岩屑砂岩。碎屑颗粒具有较好的分选性,磨圆类型以次棱角状-次棱次圆状为主,其次为次圆状。填隙物中各组分含量分布特征基本一致,胶结物含量较高,杂基含量较少,其中,胶结物中方解石含量较高,杂基中则以绿泥石为主。通过对研究区储层的物性资料进行统计分析,可以确定研究区长6～长9油层组储层均属于特低孔、超低渗储层。在纵向上,长6、长7油层组物性最好,长8油层组次之,长9油层组最差。研究区目的层的孔隙度和渗透率之间具有明显的正相关性,孔隙度均值约为8%,渗透率均值约为0.5mD,均符合致密油藏的储层条件。利用研究区长6～长9油层组探井密闭取心样品,通过普通压汞和恒速压汞试验分析表明,喉道才是决定渗流率的主要因素。

Based on the analysis of rock characteristics of Chang 6 ～ Chang 9 Reservoirs in FuxianGanquan Area,it was considered that the main rock types were mainly fine feldspar sandstone and lithic feldspar sandstone containing a small amount of feldspar sandstone.The clastic particles were better sorting.In the grinding circle type,the secondary rounded-sub-rounded circular grinding is the dominant,The main type of grinding circle was mainly sub-angled-sub-circular,followed by sub-circular.The content distribution of each component in the fillings was basically the same,the content of the cementation was higher with less matrix,in which the content of calcite in cement was higher,and the chlorite is the main content in the matrix.Through statistical analysis of the physical properties of the reservoir in the study area,it can be determined that the Chang 6～Chang 9 Reservoirs in the study area belong to ultra-low porosity and ultra low permeability reservoirs.In the longitudinal direction,Chang 6～ Chang 7 Reservoirs have best physical property,the physical property Chang 8 Reservoir is next,the physical property in Chang9 Reservoir is the worst.There is a significant positive correlation between porosity and permeability of the target layer in the study area.The reservoir lithology is fine grained sandstone,the mean porosity of porosity is about 8%,and the mean permeability is about 0.5 mD.These are consistent with the reservoir conditions of tight reservoirs.By using closed coring samples from exploration wells of Chang 6～Chang 9 reservoirs in the study area,it is shown that the throat is the main factor that determines the percolation rate through the analysis of ordinary mercury injection and constant velocity mercury injection.