快速消除井眼中“大肚子”危害的钻井液技术——在广安地区钻井中的应用

井眼“大肚子”是钻井施工中常遇到的井下复杂情况之一，现场常用变排量循环、变钻头位置循环、反复划眼、多次短起下钻拉刮、稠钻井液举砂、高密度稠钻井液举砂、水泥塞补壁等处理方法，但存在处理耗时长、岩屑不易清干净、经济损失大等问题。为此，从分析井眼“大肚子”对钻井工程的危害入手，提出消除井眼“大肚子”危害的技术思路，介绍了前置冲洗液、举砂液的室内研制与评价、现场应用等钻井液技术。试验表明，采用低漏斗黏度、低切力、高润湿反转能力的前置冲洗液与研制的具有高摩阻、高拉挂、高悬浮力、强网架结构特点的举砂液联合使用的方法可快速消除井眼“大肚子”危害，适合在类似广安地区的钻井中推广应用。

SPECIAL DRILLING FLUID TECHNOLOGY USED TO ELIMINATE POTENTIAL DAMAGES OF ENLARGED HOLE SECTION: APPLICATION IN GUANG''''AN BLOCK

Hole enlargement is one of the common downhole problems during drilling. Measures like changing pump rate to circulate, changing bit position to circulate, repetitive reaming, short trips, adopting viscous or high-density viscous drilling fluid to remove cuttings, and positioning cement plugs to make up the enlarged well section are often used. But these measures are time-consuming, not easy to clean out all the cuttings, or have high costs. In this paper, starting from analyzing the potential damages of hole enlargement to drilling engineering, the technical solutions to eliminate those damages are put forward. And the development, evaluation and field application of the preflush and cuttings-lifting liquid are introduced. The tests show by combining the preflush with low funnel viscosity, low gel strength and high wettability reversion capability with the cuttings-lifting liquid developed with high friction, high pulling force, high suspension capability, strong spatial grid structure, the potential damages of enlarged hole section can be eliminated in a very short time, applicable in Guang'an Block or similar areas.