淡水泥浆侵入条件下低对比度储层的测井识别方法研究  

Logging Identification of Low Contrast Reservoirs Intruded by Fresh Water Mud

作　　者：邵晓岩[1,2] 田三忠 王高强[2] 侯景涛[2] 刘玉峰[2] 马腾[2] 

机构地区：[1]成都理工大学沉积地质研究院,四川成都610059 [2]中石油长庆油田分公司第三采油厂,宁夏银川750006

出　　处：《石油天然气学报》2012年第12期90-92,7,共3页Journal of Oil and Gas Technology

摘　　要：淡水泥浆侵入造成鄂尔多斯盆地Y区块油层和水层电阻率对比度低,储层油层识别困难。通过侵入模拟研究,发现淡水泥浆侵入使油层电阻率增大率(饱含油砂岩层电阻率ρso/饱含水砂岩层电阻率ρsw)由3.8～6.8降至1.5～2.5;且使油层电阻率降低65%,而水层电阻率升高50%,进一步降低了油层和水层电阻率的对比度,油层测井识别不到74%。为此,通过分区块计算淡水泥浆侵入后的混合地层水电阻率,反算地层真电阻率,并应用电阻率增大率和品质因子交会图重新确定解释图版,识别率达到91.3%,提高了近17个百分点。用该方法处理了Y区块内49口井,比原始解释符合率提高了约10个百分点,有效提高了该区低对比度油层的识别率。The fresh water mud invasion caused low contrast resistivity of oil and water zones in Y Area,the reservoir identification was difficult.By simulation study,it was found out that fresh water mud invasion into the reservoir induced resistivity increase ρso(oil saturated sand resistivity) / ρsw(water saturated sand resistivity) from 3.8～6.8 to 1.5～2.5,and 65% of reservoir resistivity was reduced.But the water layer resistivity was risen by 50%.That further reduced the contrast of the reservoir resistivity.So Logging identification resistivity of reservoir was less than 74%.Therefore by block partition,a resistivity of mixed formation water after freshwater mud invasion was calculated,true formation resistivity was back calculated,and resistivity increase rate and quality factor were used to redefine crossplot.The recognition rate of 91.3% is obtained and 17% of it is raised.The method is used to in 49 wells in the Y Area.The results show that the coincidence rate is 10% higher than that of original interpretation.The recognition rate of low contrast reservoirs in the area is effectively improved by using the method.

关 键 词：低对比度 泥浆侵入 电测井响应 测井识别 油层 

分 类 号：P618.13[天文地球—矿床学] P631.81[天文地球—地质学]