沥青砂岩储层特征分析、岩性识别及其应用

Characteristic Analysis and Lithology Identification of Bituminous Sandstone Reservoirs

塔中志留系地层岩性复杂,常规测井资料识别岩性存在很大难度.以塔中志留系塔中12井区为例,通过薄片、物性、洗油洗盐洗沥青及岩电实验资料分析储层特征.在此基础上结合常规测井、电成像、ECS等测井资料进行逐点匹配,分析不同岩性在测井曲线上的响应特征;利用交会图技术、判别分析等方法建立了研究区岩性识别的标准和图版,在此基础上开展单井岩性识别.结果表明,研究区岩性以岩屑砂岩及长石岩屑砂岩为主,储层物性较差,沥青以油质沥青、胶质沥青及沥青质沥青3种形式分布于碎屑、杂基、胶结物及粒间孔隙中.结合多种测井资料,建立标准样本,使用Fisher判别分析法开展塔中志留系复杂岩性识别,经验证符合率达到86.84%.

It is very difficult to identify the lithology using conventional log data due to the complex Silurian system in the Central Tarim Basin.Taking the Silurian system in Well TZ 12 as an example,we analyze the reservoir characteristics using core slices,physical properties data,processes of washing oil,salt and asphalt and rock electricity experiment,then analyze the logging responses of different lithologies based on conventional,electrical imaging,ECS and other logging data by matching point by point,and finally establish the standards and plates for identifying lithologies in wells using crossplot and discriminant analysis and other methods.The results show that the lithologies in the study area are lithic sandstone and feldspathic lithic sandstone,and the physical properties are poor;bitumen is distributed in clastic,matrix,cements and intergranular pores as oil bitumen,colloidal bitumen and bituminous bitumen.Using multiple logging data,establishing standard samples,and using Fisher’s discriminant analysis,the lithology coincidence rate can be 86.84%in identifying the lithologies of the Silurian formation.