螺旋井眼的产生、危害和防止

Causes and Precautions of Spiral Wellbores

井眼质量一般与井眼的光滑程度或扭曲有关,由于地层和钻具相互作用的复杂性,随着进尺的增加,曲率和挠率不断变化,因此,除非采取特别措施,实际钻出的井眼基本是螺旋井眼,它的形成造成了滑动摩擦力增大、钻压传递困难、滑动钻进机械钻速低、下套管阻力大、测井仪器下放困难、钻具失效快、井眼清洁困难、倒划眼切削新岩石等问题。为了减少建井费用、提高井眼质量,必须对螺旋井眼的产生、危害及其防治进行研究。介绍了这方面研究新进展、并探讨了螺旋井眼产生的机理、危害、预防措施和未来的若干研究问题。

Hole quality is generally related to the 'smoothness' of wellbores, or, sometimes, to wellbore stability. This paper will demonstrate that wellbore spiraling is the primary contributor to poor hole quality and that almost every well contains some degree of spiraling unless specific actions are taken to prevent it. Wellbore spiraling can causes more drag , less WOB , lower ROP , more difficult to run casing , more BHA failure , bad hole cleaning and back reaming etc. But at present, when borehole quality is mentioned, no one talks about borehole tortuosity and spiraling, and little work was done to analysis spiraling reasons, harm and precautions. This paper introduces new development of research, discusses borehole spiraling and provides some solutions and advices for the further research.