樊川区长6_1低阻油层成因分析及识别方法

樊川区延长组长6_1油藏普遍发育低阻油层,给测井解释人员在油层识别上造成一定难度。通过实验和生产数据的分析对比,结合樊川区长6_1层地质特征,对长6_1低阻油层的成因进行了分析,借助交会图法和计算自然电位重叠法对其进行识别。分析表明,长6_1储层的复杂孔隙结构导致地层束缚水饱和度高,地层水矿化度高,黏土矿物增强导电性等因素是造成研究区长6_1低阻油层形成的主要原因。采用交会图法和计算自然电位重叠法可以有效地识别低阻油层。

Genetic analysis and identification methods of Chang 6_1 low-resistivity oil layer in Fanchuan area

Chang 61 reservoir of Fanchuan area generally belonged to low resistivity reservoir,which made it difficult in oil layers' identification.By contrasting laboratory tests and production data,combined with geological characteristics of Chang 61 reservoir,by means of the methods of cross-plot and natural potential overlaps,the genetic analysis of low resistivity was carried out.The results indicated the complicated pore structure of Chang 61 led to higher irreducible water saturation and higher formation water salinity,and the increased conductivity of clay minerals was the main reason of low resistivity.It was concluded the methods of cross-plot method and natural potential overlaps could effectively identify the low resistivity reservoir.