Study of cuttings transport using stable foam based mud in inclined wellbore

Abstract

Drilling of high angle, horizontal and other more complex trajectory wells are common strategies to economically produce hydrocarbon from the reservoirs. During directional drilling, hole cleaning is a vital aspect which needs to be monitored and controlled. For this purpose, foam-based mud using the Under Balanced Drilling technique (UBD) is employed to obtain a better cutting transport. Solid particle is one of the lubricating agents that is widely used in water-based mud. Previous studies have shown that microbeads could significantly reduce the friction in water-based mud. However, the application of polymer beads in foam-based mud is yet to be proven. Similar to the improvement in the water-based mud, it is expected that polymer beads such as Styrene Methacrylate could enhance the rheological properties of the foam-based mud. The polymer beads might significantly reduced the torque and drag by reducing the coefficient of friction of the foam-based mud. Polymeric particles could act as the foam or emulsion stabilizer which improved the stability of the foam. The half-life of the bubbles could be extended due to the addition of polymers. The fine sizes of the polymer beads were enhanced the stability of bubbles. Theoretically, the gas phase in the foam drilling mud was pulled the cuttings upward because of their buoyancy, thereby counteracting the gravity force. Therefore, the more stable the bubble in the foam drilling, the better the cuttings transportation will be. Introduction of polymer beads in the foam-based mud improved the foam stability. Reduction of the torque and drag force improved the carrying capacity of the cuttings in directional drilling. The suitable lubricating agent can reduce the drilling operation problems such as stuck-pipe. This will result in smooth drilling operation and great benefits in term of economy.