Drilling fluids is now widely used in oil, gas drilling and other drilling projects. By using the solids control equipment, the drilling fluids could be recycled many times for cost saving and environment protection. This article would give a simple introduction on the function of the drilling fluids.
What is the function of the drilling fluids
1. Flushing bottom of the well – the high pressure drilling fluids get out from the drill bit would flush the bottom of the well then make no obstacles for drilling process.
2. Carry cuttings – the drilling fluids would take the drilling cuttings out to the ground surface for mud cleaning process.
3. Balance formation pressure – due to very deep drilling, the drill bit may go through different formations such as rock formation and ground water formation. The drilling fluids here functioned to prevent the ground water getting into the drilling well. This would protect the geological structure.
Besides, the drilling fluids could also function to cool down and lubricate drill bit, protect borehole wall and provide downhole power.
To fully obtain the drilling fluids advantages, there are several requirements on the drilling fluids.
1. The drilling fluids should meet demand for drilling mud recycling
Drilling cycle request the drilling fluids low pump pressure (low fluid viscosity), excellent ability to carry cuttings (dynamic force is high), low starting pump pressure (low static shear force), good lubrication performance, low friction (less solids particles)
2. Maintain the stability of borehole
It is requested to use drilling fluids column to balance the formation pressure. And when drill oil and gas layer, the drilling fluids is also needed to balance the pressure of the oil and gas. That would request a stable density of the drilling mud.
3. Oil and gas protection
After drilling oil and gas layer, drilling fluid contacts with oil and gas. To prevent drilling fluid damaging the oil and gas layer, the drilling fluids should be small filtration, thin mud cake, low solid content and low filtrate of hydration etc.
4. Protect the nature environment
Drilling fluid often contains oil and crude oil, diesel oil and a large number of chemical agents. In order to prevent the possible impact on nature environment, non-toxic, harmless drilling fluids should be used.