吉林油田甲酸盐无固相欠平衡钻井液技术

Solid-free Formate Drilling Fluid Technology Used in Under Balanced Drilling of Deep Wells in Jilin Oilfield

吉林油田英台井区地温梯度高,约为3.7～4.0℃/100 m,欠平衡井的欠压井段为登娄库组和营城组,完钻井深在4 000 m左右。为进一步提高机械钻速、更好地保护储层,设计使用抗高温无固相钻井液。针对该地区储层特点,优选出了甲酸钠无固相钻井液配方,其主要处理剂为生物聚合物类增黏剂HHTN-1、磺化聚丙烯酰胺类抗盐降滤失剂HHJL-1和改性聚合醇类储层保护剂HHYB-N。龙深6等4口井通过应用该钻井液技术进行欠平衡钻井施工发现了高产气田,与同区块同井别应用其它体系的单井相比,日产量提高了15%;机械钻速与使用抗高温成膜聚合物钻井液或水包油钻井液的井相比,分别提高了57%和20%。

In blocks of Yingtai Jinlin oilfield,the geothermal gradient is 3.7℃-4.0℃/100 m,and the total depth is about 4,000 m.The high temperature clay-free formate drilling fluid system is applied in under balanced drilling to control density,keep borehole stable,improve rate of penetration,decrease drilling period,and prevent damage of reservoir by solid phase.This drilling fluid is mainly composed of biopolymer HHTN-1,filtrate reducer HHJL-1 and reservoir protection additive HHYB-N.The technology is applied successfully in 4 wells,compared with the wells with polymer and oil-in-water drilling fluid systems,the rate of penetration is increased by 57% and 20%,and the daily productions are improved by 15%.