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空气钻井因其钻速快，防漏制漏效果好，具有常规钻井液不可比拟的优越性，但由于含氧量高，当其遇到地层水时，钻具腐蚀情况较为严重。以伊朗TABANK气田14井为例，该井地层水为腐蚀介质，研究了温度、空气压力、含砂量、砂子粒度、转速和pH值对S135钻杆钢的腐蚀影响，为以后空气钻井防腐提供了参考依据。试验结果表明：腐蚀速率随温度、空气压力或转速的升高而增大，在低温或低压下，腐蚀为均匀腐蚀；高温或高压下，呈现非均匀腐蚀现象。随腐蚀介质中含砂量的增多，石英砂对S135钢的磨蚀作用增强，腐蚀速率逐渐增大，石英砂越细，则其磨蚀作用越强，腐蚀越明显；均匀混合的石英砂较单一级配的石英砂对钢片的腐蚀程度大。腐蚀速率随pH值的升高而降低，碱性条件有利于防腐。

INVESTIGATION ABOUT FACTORS OF DRILLING TOOLS CORROSION FOR AIR DRILLING 1)

Air drilling fluid has much more advantages than the conventional drilling fluids for its high penetration rate and good lost circulation control. But high oxygen content in the air will cause serious corrosion of drilling tools when encountering formation water. Taking Well 14 formation water of TABANK Gas Field in Iran as the corrosion media for example, the influence of temperature, air pressure, sand content, sand granularity, rotary speed and pH value on S 135 drilling pipes is investigated, which provides the reference for corrosion control in air drilling. The test results show the corrosion increases as the temperature, air pressure, or rotary speed rises. With low temperature and pressure, the corrosion appears homogeneous. With high temperature and pressure, the corrosion appears non-homogeneous. The erosion effect and corrosion rate of silica sand on S 135 steel pipes increases as the sand content rises in the corrosion media. The thinner the silica sand is, the stronger its erosion effect is, and the more obvious the corrosion is. Homogeneously mixing silica sand has more corrosion than single size silica sand. Corrosion rate decreases as pH value increases. Basic environment is in favor of corrosion control.