鄂尔多斯盆地定边油田樊学地区长4+5油层组储层特征及物性影响因素研究

根据对鄂尔多斯盆地定边油田樊学地区长4+5储层特征、成岩作用及物性影响因素研究结果表明,长4+5储层岩性主要为岩屑长石砂岩、长石砂岩,分选性总体中等-较好,磨圆度较差。孔隙类型以残余粒间孔和溶蚀孔为主,分别占总孔隙的59%、34%。孔隙度变化在0.2%~17.6%,平均值为8.5%;渗透率主要分布在0.1×10^-3~0.4×10^-3μm^2,平均值为0.25×10^-3μm^2,为特低孔特低渗储层。胶结物以方解石等碳酸盐胶结物、黏土矿物和硅质为主。原始沉积组分、碳酸盐胶结作用对储层物性具有重要的影响,塑性物质含量高的储层主要因压实作用变致密。碳酸盐胶结物含量高的储层因胶结作用变致密,刚性物质含量高的储层因刚性物质支撑作用保留较多残余粒间孔及易溶组分的溶蚀作用物性较好。长石、石英等刚性物质含量越高,千枚岩、板岩、云母等塑性物质和碳酸盐胶结物含量越低,储层物性越好。

Characteristics and Controlling Factors of the Reservoirs of 4+5th Member of Yanchang Formation in Fanxue area,Dingbian Oilfield,Ordos basin

Studies on the characteristics of the Reservoirs,lithology and the controlling factors of 4+5th member of Yanchang Formation in Fanxue area of Dingbian oilfield in Ordos basin show that the lithology of the reservoir of 4+5nd member are mainly arkose and lithic feldspar sandstone,with sorting from medium to good,and a poor psephicity.The pore types are mainly residual intergranular pores and dissolution pores,accounting for 59%,34%of the total pore respectively.The porosity of the reservoir ranges from 0.2%to 17.6%,with the average of 8.5%.The permeability ranges from 0.1×10^-3 to 0.4×10^-3μm^ 2,with the average being 0.25×10^-3μm^ 2.The main cements are carbonate,clay and quartz.The contents of sedimentary component,carbonate and clay cement have important impact on the reservoir quality.The reservoir with higher content of rigid particles,lower content of plastic particles and carbonate cement has good quality.The reservoir with higher content of plastic particles has lower porosity and permeability because of compaction,while the reservoir with higher content of carbonate cement has lower porosity and permeability because of carbonate cementation.The porosity and permeability of reservoir increase with the higher content of rigid particles and the lower content of plastic particles and carbonate cements.