可循环氮气泡沫钻井液技术

Recirculable Nitrogen-foam Drilling Fluid Technology

针对现有钻井液技术在钻压力系数低于0.8的地层时存在的诸多不足,提出了可循环氮气泡沫钻井液技术。对发泡剂及配套处理剂进行了优选,确定了低压条件下的可循环氮气泡沫钻井液配方。性能评价结果表明,该体系具有较好的抗盐、抗温及耐油性能,可循环次数在10次以上。根据欠平衡钻井的技术要求,制定了可循环氮气泡沫钻井液的现场施工工艺。该技术在史3-3-斜91井和樊142-8井的欠平衡钻进中进行了应用。应用结果表明,该钻井液密度低,有利于提高钻速,可以作为解决超低压地层的井漏及油层保护难题的技术。

A recyclable nitrogen-foam drilling fluid technology was introduced in drilling wells with formation pressures less than 0.8.The mud formulation for drilling in low-pressure-gradient formations was presented,including the optimization of foaming agents and other chemicals required,based on the laboratory researches.Techniques involving the filed practice of the foaming mud were made in accordance with the requirements of under-balanced drilling.This mud can be used for more than 10 circulations.The application of this mud in wells SHI-3-3-XIE-91 and FAN-14208 showed that the low rate of penetration,mud losses and reservoir damage which had been difficulties in the past,were successfully overcome.