Generally, a cleaning product such as a detergent is more effective on cleaning surfaces in a foam form. The air bubble increases the contact time between the cleaning products and the surfaces. As a consumer product, a cleaning foam is more preferable than plain cleaning chemicals.
In the oil field development proposal, flow assurance is one item that must be considered in the budgetary. Some fields have wax or hydrates problems. Others have sand, water, CO2 or H2S problems. The best method must be chosen to overcome the problems or to clean the solid deposits.
In gas-dominated hydrocarbon flows, slugging flow is frequently encountered during production operation. Vibration, noise, and significant pressure loss due to gas slippage are the effect of the flows. Slug flows tend to allow deposition of wax, asphaltene, and hydrates in the pipeline of the oil and gas system.
Foaming could mitigate flow assurance issues. Foaming gas well downhole is frequently done to lift water and avoid excessive downhole backpressure. During the injection of foaming chemicals and/or agents, some additives are optionally mixed. Foam is also believed to reduce fluctuations in the flow rates.
Creating the foam on surface flows can also be applied to mitigate flow assurance issues. A foaming agents such as surfactans or detergent will help to form the cleaning foam. By adding some solid partichels, the foam will become high density foam which can stay on the bottom of the flow and clean the oil and gas piping. The cleaning foam will mix gas and liquid including potential entities in them and avoid deposition. Since the foam flows are more uniform, the flows will have lower pressure loss and lower energy to transport the fluid.
Referring to Figure 1, the following steps for mitigating flow assurance issues is simple:
- Generating the cleaning foam, directly in the flowline or through an additional loop.
- Transporting the cleaning foam with the hydrocarbon.
- De-foaming, directly in the flowline or through an additional loop.
Foaming and de-foaming can be performed mechanically such as using a pump to mix gas and liquid or mixer. By creating turbulent flow through a valve or choke also can generate foam. Cycloning can be used to de-foam.
Recommended reading and an application of foam for skin care: