Drilling fluid bubbles and defoaming

1. Causes of Drilling Fluid Foaming

1. Drill into the air layer. Gas in the formation invades the drilling fluid, causing the drilling fluid to foam.

2. 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

1. Reduce the self-suction force of the mud pump and reduce the displacement of the mud pump.

2. Reduce the ability of drilling fluid to carry cuttings.

3. 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.