云南侏罗系“红层”复杂情况的处理方法

Yunnan Jurassic“Red Beds”Complications Processing

云贵川地区中生界侏罗系坝注路组,岩性为紫红、暗紫红色泥岩夹细砂岩,局部夹灰、灰绿色粉砂岩、泥灰岩及其透镜体,因其以红色为主,俗称"红层",吸水性强,极易风化,一旦失去稳定性,漏失、掉块、坍塌现象严重,如果处理不当极易发生卡钻、埋钻等事故,甚至造成钻孔报废。在充分研究区内地层特点的基础上,从调制钻井液、钻具结构调整和注浆护壁等方面入手,采用高密度钻井液体系、小径钻具等多项措施,从而的完成了施工任务,为同类地区的钻探施工提供了借鉴。

The lithology of Mesozoic Jurassic Bazhulu Formation in Yunnan, Guizhou and Sichuan provinces is purplish red, dark pur-plish red mudstone intercalated with fine-grained sandstone, locally gray, grayish green siltstone, marl and its lens. Because of red dom-inated, thus known as＂red beds＂. The rocks have high hydroscopicity, easy to weathering, once lost stability will cause serious loss ofcirculation, off block and sloughing, if misconducted,then drill rod sticking and burying will happen, even borehole abandoned. On thebasis of full study of strata characteristics in the area, proceed with aspects of drilling fluid preparation, drilling tool configuration andgrouting, wall protection, using multiple measures of high density drilling fluid system and small diameter drilling tools, thus accom-plished drilling tasks and provided reference for drilling operation in areas of same type.