我队用φ46小口径人造金刚石钻进436号孔时,在井深384米处遇到炭质页岩层,坍塌缩径严重,钻具下不到井底.起初采用扩孔下暗管(φ55)保壁,效果较好,挡住了第一层炭质页岩,但进尺十几米后又遇到另一层页岩,此时,决定使用低固相泥浆护壁.泥浆用的是当地粘土(含Si0_267%,Al_2O_320.8%,Fe_2O_36.4%,MgO5.8%).在中南矿冶学院的协 When I drilled No. 436 hole with φ46 small diameter synthetic diamond, the team encountered a carbonaceous shale layer at a depth of 384 meters, and the diameter of the collapsed layer was serious and did not reach the bottom of the well under the drilling tool. At first, Preservation of the wall, the effect is better, blocking the first layer of carbonaceous shale, but ten meters into the footage and then encountered another layer of shale, this time, decided to use low solid mud retaining wall. Si0_267%, Al_2O_320.8%, Fe_2O_36.4%, MgO5.8%). In the South China Institute of Mining and Metallurgical Association