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反循环钻进工艺具有钻进效率高,成井质量好,钻进费用低等特点。近20多年来,许多国家采用这种钻进方法,收到了很好的效果。一、反循环钻进工艺的优越性正循环钻进时,泥浆由泥浆泵送出,经过提引水笼头和钻杆流至孔底,冷却钻头后,再经钻杆与孔壁之间的环状间隙返回孔口同时将孔底的岩屑排出。如果增大孔径,钻杆与孔壁之间的环状间隙也随之增大,泥浆的上返速度就会大大降低,影响孔底岩屑的排出。钻进过程中,被钻头松动、破碎的地层颗粒不能及时排出孔外,就限制了钻井的进尺速度。为了解决加快进尺与排出岩屑的矛盾,人们就设法增大泥浆泵的排量。石
The reverse circulation drilling process has the characteristics of high drilling efficiency, good well completion quality and low drilling cost. In the past more than 20 years, many countries have adopted this drilling method and have received very good results. 1. Advantages of Reverse Circulation Drilling Process During positive circulation drilling, the slurry is pumped out by the mud pump, and after drawing the tap and the drill pipe to the bottom of the hole, after cooling the drill bit, the ring between the drill pipe and the hole wall is passed. The gap is returned to the orifice at the same time to expel debris from the bottom of the hole. If the aperture is increased, the annular gap between the drill pipe and the hole wall will also increase, and the mud return speed will be greatly reduced, affecting the discharge of cuttings at the bottom of the hole. During the drilling process, the formation particles that are loosened and broken by the drill bit cannot be discharged out of the hole in time, which limits the speed of drilling. In order to solve the contradiction between speeding up and discharging the cuttings, people try to increase the displacement of the mud pump. stone