G-105钢在盐水钻井液中的腐蚀行为

为了解决盐水钻井液对钻具的腐蚀,通过对现场钻杆腐蚀产物的EDS分析发现,其主要成分为铁的氧化物Fe2O3;盐水钻井液对钻具的腐蚀主要是氧的去极化腐蚀,且腐蚀产物疏松,对钻杆保护作用较差.通过室内动态模拟试验发现,随着温度升高和转速增加,G-105钢在盐水钻井液中的腐蚀速率都会增加;含盐量较低时(＜3%)泥浆中的盐分对溶解氧的排驱作用较小,主要起增强导电性作用,此时,G-105钢在盐水钻井液中的腐蚀速率随着盐含量的增加而增大,随后,盐对溶解氧的排驱作用占优势,腐蚀速率随盐含量的增加而降低.

Corrosion Behaviors of G-105 Steel in Saltwater Drilling Fluids

To solve the corrosion of drill pipe, corrosion mechanism of G-105 drill pipe in saltwater drilling fluid was investigated. The corrosion product on local drill pipe is mainly consisted of Fe_2 O_3 analyzed by EDS, and the corrosion of drill pipe is almost caused by the depolarization of dissolved oxygen.Surface loose corrosion product has little protection for drilling pipes. Dynamic simulation test results in laboratory show that the corrosion rate of G-105 steel in saltwater drilling fluids increases with the increase of temperature and rotate speed. When the content of NaC1 in saltwater drilling fluids is lower ( below 3% ), it has little repulsion on oxygen but enhances the conductivity of drilling fluid, so that the corrosion rate of G- 105 steel in saltwater drilling fluids increases with the rise of NaC1 content up to 3%.Subsequently, the corrosion rate decreases with the rise of NaC1 content for it becomes dominant to repulse the dissolved oxygen.