【摘要】 苏丹3/7区地层胶结疏松,钻进过程中常伴有严重超拉、遇阻及部分井段井径扩大等井下复杂情况。为 解决这一技术难题,在对常规KCl／聚合物钻井液体系进行详细的室内试验评价的基础上,结合该地区地层失稳的特 点,提出了对所用钻井液进行改性的技术思路。通过对现用KCl/聚合物钻井液改性前后性能的对比试验,提出了两 套政性的KCl/聚合物钻井液配方,并给出了相应的配制方法和维护技术。苏丹3/7区现场4口井的应用证明,改性 后的KCl/聚合物钻井液体系具有抑制性能好、包被能力强、流变性优良等特点。完井电测数据表明,最大井径扩大 率由68%下降至8％,同时使建井周期缩短28％。改性KCl/聚合物钻井液体系可在苏丹3／7区推广应用。更多还原

【Abstract】 The Block 3/7, Sudan is characterized by its soft and sticky claystone. The wells drilled in this area have experienced many drilling fluid related downhole problems, such as serious overpull and washed out hole sections, which have adverse effects on drilling operation. To solve these technical problems, the research for modification was carried out and two kinds of modified KCl/polymer drilling fluids were developed. The forming procedures and maintenance techniques based on better understanding of wellbore instability mechanisms also were provided. The applications in four wells indicate that the new drilling fluid system show excellent inhibitive ability and favorable rheological properties. The modified KCl/polymer drilling fluids can reduce the maximum hole enlargement rate from 68% to 8% , and shorten the well construction time by 28%. At present, these two types modified drilling fluids have been widely applied in Block 3/7, Sudan.更多还原