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目前,在地质勘探岩芯钻探的实际生产过程中,起下钻具仍是不可取消的重要工序. 在起下钻具的过程中,由于钻具在充满泥浆的钻孔中做直线上下运动,以致使钻孔环状间隙的泥浆产生剧烈的波动,从而对孔壁形成压力激动. 压力激动实质上是对孔壁的一种波动压力.一般可以概括地认为,由下钻引起的波动压力为挤压压力,由起钻引起的波动压力为抽吸压力. 由于波动压力的产生,对钻孔的顺利安全施工十分有害.特别是对某些不稳定地层尤为突出.最常见的是,由于下钻形成的挤压压力过大,而造成钻孔漏失:由于起钻形成的抽吸压力过大,而造成承压水喷出孔口,油、气、地下热
At present, during the actual production process of geological exploration core drilling, it is still an irreplaceable important step in the process of drilling core drilling.In the process of lifting the drilling tool, since the drilling tool moves up and down in a straight line in the hole full of mud, So that the drilling of the annular gap of the mud caused a sharp fluctuations in the pore wall to form pressure-excited pressure stress is essentially a pressure on the pore wall pressure can generally be generalized that the fluctuation caused by drilling pressure is Extruding pressure, fluctuating pressure caused by boring is suction pressure.Because of fluctuating pressure, it is very harmful to smooth and safe construction of drilling hole, especially for some unstable formations.Mostly, Drill formed by the extrusion pressure is too large, which led to the loss of drilling: Due to the formation of the drill suction pressure is too large, resulting in confined water spray orifice, oil, gas, underground heat