页岩气田回注水中低浓度过氧化氢安全风险研究

Study on Safety Risk of Low Concentration Hydrogen Peroxide in Reinjection Water of Shale Gas Field

过氧化氢作为“最清洁”的环保型氧化剂,可以直接氧化气田水中的各种有机物质,处理效果明显,成本低。然而,双氧水是一种热不稳定的物质,与其他杂质接触后极易分解释放大量的热量、氧气和水蒸汽,同时,双氧水分解产生的氧气也可能会加速地面管柱和井下油套管腐蚀。本文开展了回注气田水中过氧化氢浓度现场检测,根据过氧化氢浓度检测结果,从回注气田水双氧水安全使用浓度、燃爆风险和腐蚀风险等三个方面,分析了回注气田水中过氧化氢的安全风险。研究结果表明,双氧水处理回注气田水的安全浓度为30%;回注气田水池和气田水回注井筒中因过氧化氢分解产生氧气引起的燃爆风险低,安全风险可控;低浓度过氧化氢溶液分解时间长、产氧率低,对接触氧化氢溶液的地面设备和回注管道腐蚀可以忽略不计,安全风险可控。

Hydrogen peroxide, as the cleanest’ environmentally friendly oxidant, can directly oxidize various organic substances in gas field water, with obvious treatment effect and low cost. However, hydro-gen peroxide is a thermally unstable substance, which can easily decompose and release a large amount of heat, oxygen and water vapor after contacting with other impurities. At the same time, the oxygen generated by the decomposition of hydrogen peroxide may also accelerate the corrosion of surface string and down hole tubing and casing. In this paper, the on-site detection of hydrogen peroxide concentration in reinjection gas field water was carried out. According to the detection results of hydrogen peroxide concentration, the safety risk of hydrogen peroxide in reinjection gas field water was analyzed from three aspects: Safe use concentration of hydrogen peroxide in reinjection gas field water, explosion risk and corrosion risk. The results show that the safe concen-tration of hydrogen peroxide treated reinjection gas field water is 30%. The deflagration risk caused by the decomposition of hydrogen peroxide to produce oxygen in the reinjection gas pool and gas field water reinjection wellbore is low, and the safety risk is controllable. Low concentration hydrogen peroxide solution has long decomposition time and low oxygen production rate. The cor-rosion of ground equipment and reinjection pipeline exposed to hydrogen oxide solution can be ig-nored, and the safety risk is controllable.