钻井液常见污染问题及处理方法探讨

摘要

Drilling fluid with superior property is one of the fundamental conditions for successful drilling. However, drilling fluid tends to metamorphose and lose efficacy because of contamination by H2S, gypsum, saline water, and CO2. This case will largely jeopardize drilling safety and increase cost. Therefore, the essential reason triggered the pollution by H2S, gypsum, saline water and CO2 was analyzed; using basic chemical theories, economical and effective disposal method were proposed from enhancing the fluid contamination resistance and handling polluted fluid. The results show that the primary cause of this four materials mentioned contaminating drilling fluid is that they reduce the pH and break the colloidal form, Zn2(OH)2CO3 can effectively eliminate the H2S that intrudes into drilling fluid, contamination from gypsum and calcium-based saline can be solved by combining Na2CO3 and NaOH, and that CaO can recover the property of drilling fluid polluted by CO2. These disposal methods are of low cost, but the dose should be controlled strictly, and desired results could not be obtained for excessive or insufficient quantity.%性能良好的钻井液是钻井施工成功的基本条件之一,但钻井过程中钻井液易被H2S、石膏、盐水和CO2等污染而变质失效,严重影响钻井施工安全,增大施工成本.为此,剖析了H2S、石膏、盐水和CO2等4种污染源污染钻井液的根本原因,应用基础化学理论,从提高钻井液自身抗污染能力和对已污染钻井液的处理2个方面提出了经济、有效的处理方法.结果表明,这4种物质污染钻井液的根本原因是其降低了钻井液的pH值和破坏了胶体形态；Zn2(OH)2CO3可有效除去侵入钻井液的H2S,Na2CO3和NaOH配合使用可解决石膏和钙性盐水污染问题,CaO能恢复被CO2污染的钻井液的性能,这些处理办法的成本都较低,但需要严格控制药剂的加量,药剂过量或不足都无法达到预期效果.