Overview：
Aquamax Drilling Fluid is a high-performance water-based drilling fluid system based on the mechanism of "reverse osmosis", which can significantly improve the efficiency of the semi permeable membrane between mud and shale interface. The core agent is a chemical plugging agent, which is dissolved in high pH environment. When the pH of the water phase in contact with shale formation is reduced, it's going to crystallize and the crystal salt particles will block in the shallow layer of mud shale to form internal mud cake, so as to reduce the permeability of mud shale interface, improving the efficiency of mud shale semi permeable membrane and forming reverse osmotic pressure. When the activity of drilling fluid filtrate is lower than formation water, it will slow down the transmission speed of pore pressure and prolong the period of wellbore stability. The system has been successfully applied in the Western South China Sea and Missan field of Iraq. It has successfully overcome the challenge of wellbore instability while drilling reactive shale intervals.
Applicability：
Temperature: ~180 ℃；Density: 1.2~1.8 g/cm3
Characteristics：
Stable rheology；Enhanced shale inhibition；Enhanced plugging ability；Maintaining shale stability for longer period of time；Increased ROP.
Background:
A well in WS Block, South China Sea, has a well depth of 3910m. In previous operations in this block, the shale formation is very vulnerable to instability, borehole wall collapse, peeling, etc., which leads to difficulties in tripping, and the problem of electrical resistance card is very serious. After the trial operation of this system, not only the drilling of each well section is completed at one time, but also the direct tripping of some well sections is realized, without any complex situation.
Challenge:
1. Shale well wall is prone to instability, collapse and peeling.
2. Well depth: 3910 m
Job results:
AQUAMAX system has been successfully applied in the South China Sea and Missan Oilfield in Iraq, showing good rheology, inhibition, plugging and lubrication. The borehole wall is stable, reducing downhole complications and improving drilling efficiency.
