苏丹六区低伤害防塌钻井液技术

An Anti-Sloughing and Low-Damage Drilling Fluid Used in Block 6,Sudan

针对苏丹六区钻井过程中易于发生井壁失稳和对储层损害大的问题,基于理想充填暂堵剂和成膜剂的协同增效作用,在该地区原用KCl/聚合物钻井液基础上,优选出一种新型低伤害防塌钻井液。室内试验结果表明,该钻井液具有优良的抑制性能,与原用钻井液相比,可显著降低钻井液的滤失量,岩心渗透率恢复率可提高至88.32%,具有显著的储层保护效果。该钻井液在两口试验井三开井段进行了现场试验,并取得了良好的井眼稳定及储层保护效果,有效解决了泥页岩地层井壁失稳和保护高孔、高渗储层的两大技术难题。

Wellbore sloughing and reservoir damage are prone to occur during drilling formations with high porosity and high permeability in block 6,Sudan.A low damage anti-sloughing drilling fluid was developed based on original KCl polymer drilling fluid using ideal bridging agents along with film forming agent.Lab tests indicate that this drilling fluid performs good inhibition compared with original one,and can reduce fluid loss remarkably and improve core recover ratio up to 88.32%,and behaves remarkable reservoir protection effectiveness.This drilling fluid was tested in two wells during drilling the third hole sections and achieved better wellbore stability and reservoir protection,and resolved technical challenges of both wellbore caving and formation damages.