泡碱处理粘卡在皖亳地1井的应用

Application of alkali treatment for sticking in Well WBD-1

摘要:

当钻柱贴靠井壁时，在钻井液液柱压力与地层压力的压力差作用下，易发生粘附卡钻，给后续钻井施工带来挑战。本文分析了基于粘土的低固相钻井液体系泡碱解卡机制，探讨了不同浓度氢氧化钠溶液对滤饼的影响，结果显示：随时间变化OH^-与Ca²⁺等结合对滤饼作用呈现递增趋势，同等条件下6%浓度氢氧化钠溶液对滤饼“消融”效果优于其他浓度。通过处理皖亳地1井粘卡效果表明，泡碱处理基于粘土的低固相钻井液解卡相比泡酸、泡油快速有效，同时能够减少对后续钻井液干扰，降低钻井成本。该经验可对同类粘卡处理提供借鉴作用。

Abstract:

When the drill string is pressed against the wellbore due to poor mud cake quality， it is prone to sticking under the pressure difference between the drilling fluid column pressure and the formation pressure， which poses a challenge to subsequent drilling construction. In this paper， the mechanism of releasing filter cake in low solid drilling fluid system based on bentonite is analyzed， and the dissolution of filter cake in different concentrations of sodium hydroxide solution is discussed through experiments. The results show that the combination of OH^- with Ca²⁺ and Mg²⁺ increases with time and the 6% sodium hydroxide solution has the better effect on filter cake under the same condition. The application in Well WBD-1 shows that compared with acid soaking and oil soaking， the treatment time of foam alkali is faster， which can avoid larger downhole complexity， reduce the interference to the subsequent drilling fluid and save the drilling cost. The results have a reference value for the similar sticking processing.