中国南方地区碳酸盐岩储层高电阻率水层地质成因——以川西地区下二叠统栖霞组为例  

Geologic origin of aquifer with high resistivity in the carbonate reservoirs in South China:A case study from the Lower Permian Qixia Formation in West Sichuan Basin

作　　者：黄东[1] 汪华[1] 陈利敏[2] 袁小玲[1] 石学文[1] 

机构地区：[1]中国石油西南油气田公司勘探开发研究院 [2]中国石油东方地球物理公司信息技术中心

出　　处：《天然气工业》2012年第11期22-26,113-114,共5页Natural Gas Industry

摘　　要：随着油气勘探工作的不断深入,一些有别于常规测井的地质现象也不断被发现,其中报道得最多的是碎屑岩中发现的低电阻率油气层,而对碳酸盐岩中的高电阻率水层却鲜有报道。为此,以四川盆地下二叠统栖霞组储层为例,分别从储层特征、储层充填物特征以及地层水性质出发,研究分析了造成碳酸盐岩储层中水层电阻率高的地质原因。结果表明,除了工程原因外,高电阻率水层的成因主要有:①碳酸盐岩储层致密导致储层电子导电能力降低,从而形成高电阻率;②碳酸盐岩储层内沥青的广泛分布导致储层电子导电能力降低,也可形成高电阻率;③储层中的流体为淡水时,将导致离子数量减少,降低导电能力,测井解释时其电阻率特征类同于油气层,电阻率值较高。该研究成果有助于提高致密碳酸盐岩地区测井解释的符合率。More and more geologic phenomena distinguished from those in a normal well log analysis appear successively along with the deepening of hydrocarbon exploration.Up till now,most reports have focused on low resistivity oil/gas layers in clastic reservoirs,but very few on high resistivity aquifers in carbonate reservoirs.In view of this,in a case study from the Lower Permian Qixia Formation reservoir in the Sichuan Basin,we studied the geologic reasons of high-resistivity aquifers in the carbonate reservoirs in respect of reservoir characteristics,reservoir filling features and formation water property.In conclusion,apart from the engineering factors,the following factors are also presented herein.(1) The tightness of carbonate reservoirs lowers the conductivity of electrons in the reservoirs,which results in high resistivity.(2) The wide distribution of bitumen in the carbonate reservoirs also lowers the conductivity of electrons in the reservoirs,thus leading to high resistivity.(3) If the aquifers contain fresh water,the amount of ions will decrease,lowering conductivity;quite similar to that of hydrocarbon layers in well log interpretation,thus the resistivity of the aquifer is very high.This understanding provides good reference for logging interpretation and exploration in the areas with tight carbonate reservoirs.

关 键 词：中国南方 碳酸盐岩 高电阻率水层 成因 储集层特征 充填物 地层水 四川盆地 早二叠世 

分 类 号：P618.13[天文地球—矿床学]