旋冲钻井技术在逆掩推覆体地层的应用

在玉门青西油田窟窿山背斜构造南翼和金海子构造,由逆掩推覆带推覆上来的志留系及石炭-二叠系等老地层具有地层高陡、岩石可钻性差等特点,致使钻井过程中钻进效率低、井斜控制难.旋冲钻井技术是钻进硬岩的有效方法,为解决逆掩推覆体地层钻进难题,在玉门油田窿¨4和金海1两口井应用了DGSC型液动冲击器及配套技术,取得了较好的效果,机械钻速提高30%以上.介绍了逆掩推覆体地层特点和钻进难点,液动冲击器的特点、破岩机理及现场应用情况.应用结果表明,该技术可有效地提高硬岩钻井速度、防止井斜、减缓钻头磨损、降低钻井成本,是一种在硬岩难钻地层有发展前景的钻井技术.

APPLICATION OF ROTARY PERCUSSION DRILLING TECHNOLOGY IN REVERSE THRUST NAPPE STRUCTURE FORMATION

A characteristic of the old formation of Qingxi Oilfield,such as silurian system and carboniferous-permian system,is formation high and steep,rock drillable performance badly,and lead to lower drilling efficiency and hole deviation control too hard during drilling.rotary percussion drilling technology is a efficacious method for hard rock formation,to solve the drilling difficult problem in reverse thrust nappe structure formation,DGSChydraulic impacter and matching technology is applicated in long114 and jinhai1 two wells in Yumen Oilfield,and gained a preferable effect,mechanical efficiency of penetration has increased by over 30%.Practice demonstrate that the technology can improve effectively rate of penetration,prevent hole deviation,decrease bit wear and tear,reduce drilling cost,and is a sort of better drilling technology for hard rock formation.This paper introduces reverse thrust nappe structure formation characteristic and drilling difficulty,hydraulic impacter characteristic,rock breaking mechanism and field application.