适用于页岩气水平井的低摩阻硅酸钾钻井液体系

Low Friction Potassium Silicate Drilling Fluid System For Shale Gas Horizontal Wells

当前环保形势日趋严峻,亟待广大钻井液从业者开发出一套可替代油基的水基钻井液体系,来解决页岩气水平钻进过程中存在的摩阻、井壁稳定以及井眼清洁等一系列难题。本次研究在硅酸钾钻井液强抑制、强封堵、易成膜的基础上,开发引入了一种具备协同封堵能力的强效水基润滑剂,并通过系列筛选和评价实验,构建了一套低摩阻硅酸钾钻井液体系。其润滑系数在0.08左右,抗磨砝码质量达到10 kg,具备媲美油基钻井液的润滑和抗磨性能;同时具有较低滤失量(FLHTHP小于6 mL);此外该体系还有较强的抑制和抗污染能力,流变易于控制,完全能满足页岩油气藏的开发需要。

At present,with the increasingly severe environmental protection pressure,it is more and more urgent for drilling fluid practitioners to develop a set of water-based drilling fluid system that can replace oil-based to solve a series of problems such as friction,wellbore stability and borehole cleaning in the process of shale gas horizontal drilling.In this study,a potent water-based lubricant with synergistic plugging ability was developed and introduced on the basis of potassium silicate drilling fluid’s features such strong inhibition,strong plugging and easy film-forming.Finally,the low friction potassium silicate drilling fluid was constructed through a series of screening and evaluation experiments.Its lubrication coefficient is about 0.08,and the weight of anti-wear weight reaches 10 kg,which is comparable to oil-based lubrication and anti-wear performance;at the same time,it has a low filtration rate(FL_(HTHP)<6 mL);in addition,the system has strong inhibition and anti pollution ability,and its rheology is easy to control,which can fully meet the development needs of shale oil and gas reservoirs.