甲酸盐无固相钻井液研究

Research on Solid-Free Formate Drilling Fluid

无固相钻井液因不含惰性固体颗粒,具有良好的流变性和润滑性能,用于小井眼钻井中可有效降低循环压耗。研究了密度为1.35~1.50 g/cm3的甲酸盐无固相钻井液,该钻井液抗温达120℃,抗盐达饱和,抗劣质土粉污染达10%,抗Ca2+污染达2600 mg/L。与同密度的聚磺饱和盐水钻井液相比,岩屑相对回收率由60.4%上升至94.8%,腐蚀速率降低42.28%,摩阻降低13%~22%,渗透率恢复值提高12.64%,具有更好的抑制、防腐蚀、储层保护及降摩阻效果。

Solid-free drilling fluid has good rheological property and lubricating property due to that it contains no inert solid particles,and therefore it can reduce circulation pressure loss effectively when used for slimhole drilling.Solid-free formate drilling fluid of the density of 1.35 to 1.50 g/cm3 was studied.This drilling fluid can sustain the temperature that is as high as 120℃,can tolerate salt up to saturated concentration,can tolerate inferior soil powder contamination up to 10%of inferior soil powder concentration,and can can resist Ca2+contamination of up to 2600 mg/L concentration.Compared with the case in which a polysulfonate saturated salt drilling fluid of the same density was used,the relative recovery percent of cuttings was increased from 60.4%to 94.8%,the corrosion rate was reduced by 42.28%,the friction drag was reduced by 13%to 22%,and the return permeability was increased by 12.64%when this drilling fluid was used,indicating that this drilling fluid has better effects of inhibition,corrosion prevention,reservoir protection,and friction drag reduction.