关键词: 油井, 结垢, 防垢剂, HEDP, 缓慢释放

Abstract:

The scaling in oil well can be effectively prevented for a longer time by using solid inhibitor. To select the inhibitor component used to produce solid inhibitor, 7 types of phosphonate scale inhibitors are evaluated, and HEDP is proved to be most effective and have a rather good properity of heatstability. From the solution of HEDP, HEDP powder can be obtained by the method proposed in the paper. One method is to neutralize the solution of HEDP with a certain concentration of NaOH, then desiccate and grind the resultant. The obtained phosphonate powder is easy to dissolve in water. Another method is to add Ca(OH)₂ into the solution of HEDP with a ratio of n(Ca(OH)₂)/n(HEDP)=1.75. After filtration, desiccation and grinding, another king of phosphonate powder, able to dissolve slowly in water, is gotten. The elemental analysis results confirm that the main constitute of the powder is Ca₂HEDP. These two types of HEDP powder can be used to prepare solid scale inhibitor by mixing with polythene.

Key words: oil well, scaling, scale inhibitor, HEDP, slow release