柴油基钻井液在涪陵礁石坝区块页岩气储层的应用

APPLICATION OF DIESEL-BASED DRILLING FLUID TO SHALE-GAS RESERVOIRS IN JIAOSHIBA BLOCK,FULING

涪陵礁石坝页岩气储层以泥页岩为主,黏土含量高,层理和微裂缝发育,极易发生井壁失稳。储层段钻进时采用柴油基钻井液,在JY6-3HF井进行了现场应用,应用中未出现因钻井液导致的井下故障,起下钻通畅,无掉块,电测井段井径扩大率均小于2%。现场应用表明,柴油基钻井液具有性能稳定、抑制性强、井壁稳定性好、润滑性强等特点,适用于页岩气水平井钻井施工。

In Jiaoshiba block in Fuling area,the shale-gas reservoirs are mainly composed of mud shale with rich clay,and bedding and microfractures often found.It is prone to sidewall instability.So,diesel-based drilling fluid should be used while drilling these reservoirs and was applied to Jiaoye 6-3HF well.During this application,there was no downhole failure and no drop piece;pipe trip was not obstructed;and hole enlargement ratio was less than 2% for measured interval.Its application shows that the drilling fluid has some advantages of stable performance,strong inhibition,good sidewall stability,and strong lubricity,which is suitable for drilling shalegas horizontal wells.