Drilling fluid bubbles and defoaming
1. Causes of Drilling Fluid Foaming
- Drill into the air layer. Gas in the formation invades the drilling fluid, causing the drilling fluid to foam.
- Drilling fluid materials contain foaming materials such as surfactants, which are added to the drilling fluid to cause the drilling fluid to foam.
2.The hazards of drilling fluid foaming
- Reduce the self-suction force of the mud pump and reduce the displacement of the mud pump.
- Reduce the ability of drilling fluid to carry cuttings.
- Reduce the proportion of drilling fluid, causing well wall collapse and causing drilling stuck accidents in the well.
3. Prevention of Drilling Fluid Foaming
- Most lubricants, such as liquid lubricants and AD dry powder lubricants, contain foaming surfactants. Therefore, before using such materials, tests must be done to detect whether they contain foaming materials.
- Simple test method at the well site: Take 500 ml of circulating drilling fluid from the wellhead, add 1% or 5 ml of lubricant, stir for 10 minutes, and observe whether the total volume increases and whether it foams.
- Without a foaming material handler, the drilling fluid will naturally not foam.
4. Treatment methods for drilling fluid foaming
- Adding liquid defoaming agent can remove bubbles from drilling fluid.
- Add the amount of 1‰, that is, 1 m3 of drilling fluid plus 1 kg of liquid lubricant slowly from the wellhead. After about 2-3 cycles, the air bubbles can be removed from the drilling fluid.
