自适应防漏堵漏钻井液技术研究

针对钻井液漏失地层非均质性强及漏失通道尺寸难以准确预知等问题,提出了自适应防漏堵漏钻井液技术。该技术无须明确预知漏失地层孔喉直径,能自适应封堵岩石表面较大范围的孔喉,对较宽孔径分布的漏层具有很好的封堵作用,封堵速度快,封堵层浅,适合于油层防漏、堵漏。室内评价表明,自适应防漏堵漏钻井液能在一定范围内对不同孔径分布的漏层产生良好的封堵作用。封堵率达到90%以上,封堵带压力强度大于9MPa,封堵厚度小于1cm,切片后渗透率恢复率达90%以上。现场应用证明,自适应防漏堵漏钻井液能有效提高地层的承压能力,并且有良好的防漏及堵漏效果。

Study on techniques of auto-adapting lost circulation resistance and control for drilling fluid

Lost circulation of drilling fluid is ubiquity in the drilled formation with severe heterogeneity, wide distribution of pore radius and unpredictability of pore radius. A kind of drilling fluid for auto-adapting lost circulation resistance and control was developed,which can rapidly generate thin and tight plugged zones in the drilled formation with wide distribution of pore radius. The laboratory evaluation shows that the auto-adapting drilling fluid system has the auto-adapting sealing effect, and the sealing ratio is over 90%. The pressure strength of sealing belt is above 9 MPa, and the sealing thickness is less than 1cm. The restored permeability in core achieves above 90%. Field application shows that the auto-adapting drilling fluid for lost circulation resistance and control can effectively increase the pressure bearing capacity of the formation. The effect of lost circulation resistance and control for drilling fluid is good.