HEM Deepwater High Performance Water-based Drilling

Overview：

HEM is a high performance water-based drilling fluid system based on inhibition of amine inhibitors, low-temperature polymer technology on rheological property, anti-accretion and gas hydrate inhibition technology. HEM has been designed for shale formation and deepwater/ultra-deepwater operations, due to its effectiveness for overcoming technical challenges, including dispersion of hydrated shales, bit balling and gas hydrate from low temperature and high pressures.

Applicability：

Temperature: 2~200 ℃；Density: 1.06~2.20 g/cm3

Characteristics：

Clay free, low viscosity and high shear stress ；Excellent rheological properties at low temperatures；High inhibition to shale；High inhibition to hydrate；Excellent cuttings carrying capacity；Low impairment on reservoir.

Background:

An ultra deep well in Yongle Block, South China Sea, with water depth of 2021m, mud line temperature of 2.6 ℃, and bottom hole temperature of 106 ℃, is operated with deep-water high-performance HEM water-based drilling fluid.

Challenge:

1. Hydrate prevention and control;

2. ECD control and lost circulation prevention;

3. Rheological control of drilling fluid under large temperature difference

Solution:

1. After adding thermodynamic inhibitor, the rheological property of drilling fluid is still controllable;

2. Monitor the change of downhole ECD in real time, and VIRTUAL MUD software timely corrects and guides on-site operation;

3. Emergency leak stoppage plan shall be prepared on site, and leak stoppage materials shall be prepared;

4. HEM drilling fluid has good rheological properties under large temperature difference;

Job results:

1. The rheological properties of drilling fluid in different well sections are good;

2. As the HEM system has strong inhibition ability, tripping is not blocked;

3. There is no complex situation in the whole well;