1·Drilling with complex pressure system is a worldwide difficult problem. Several different pressure gradient stratums exist in the same bare hole section, which is very common in the drilling process.
复杂压力系统钻井是当今钻井技术领域的世界性难题，钻井过程中常常碰到多个不同压力梯度的地层处于同一裸眼井段中。
2·The common problems and treatment of cast-in-place piles in special stratums during casting period are introduced in this paper.
特殊地层中灌注桩钻进与浇筑过程中常遇问题与处理办法。