The role of hydroxyethyl cellulose (HEC) in oil drilling is mainly reflected in the preparation and performance regulation of drilling fluid. As an important water-soluble polymer, HEC has excellent thickening, suspension, lubrication and rheological properties, which makes it play a multi-faceted role in the oil drilling process.

1. Thickener role
One of the most important functions of HEC in drilling fluid is as a thickener. Drilling fluid plays a very critical role in oil drilling. It is not only a medium for transmitting the power of drilling tools, but also plays a role in cooling the drill bit, carrying cuttings and stabilizing the wellbore. In order to achieve these functions, the drilling fluid needs to have appropriate viscosity and fluidity, and the thickening effect of HEC can effectively increase the viscosity of the drilling fluid, thereby enhancing the carrying capacity of the drilling fluid, enabling it to better bring the cuttings from the bottom of the well to the ground, and avoid deposition and clogging the wellbore.

2. Suspending agent effect
During the oil drilling process, the drilling fluid needs to keep the downhole rock cuttings, drill cuttings and solid particles evenly suspended to prevent them from settling at the bottom of the well or the well wall, causing wellbore blockage. As a suspending agent, HEC can effectively control the suspension state of solid particles in the drilling fluid at low concentrations. Its good solubility and viscoelasticity enable the drilling fluid to remain in a stable suspension state under static or low-speed flow conditions, thereby improving drilling efficiency and safety.

3. Lubricant effect
During oil drilling, the friction between the drill bit and the well wall will generate a lot of heat, which will not only accelerate the wear of the drill bit, but also may cause drilling accidents. HEC has good lubrication properties. It can form a protective film in the drilling fluid, reduce the friction between the drill tool and the well wall, thereby reducing the wear rate of the drill bit and extending the service life of the drill bit. In addition, the lubrication effect of HEC can also reduce the risk of well wall collapse and ensure the smooth progress of drilling operations.

4. Rheological regulation
The rheological property of drilling fluid refers to its fluidity under different conditions, which is crucial to ensure the safety and efficiency of drilling. HEC can adjust the rheological properties of drilling fluid so that it has good fluidity during drilling and can show strong support and suspension when needed. For example, under high temperature and high pressure conditions, the rheological properties of drilling fluid may change. The addition of HEC can stabilize its rheological properties so that it can still maintain ideal performance under extreme conditions.

5. Anti-water loss effect
During the drilling process, the water in the drilling fluid may penetrate into the formation, causing the well wall to become unstable or even collapse, which is called the water loss problem. HEC can effectively reduce the water loss of drilling fluid by forming a dense filter cake on the well wall to prevent the water in the drilling fluid from penetrating into the formation. This not only helps to protect the stability of the well wall, but also prevents formation pollution and reduces environmental risks.

6. Environmental friendliness
HEC is a natural cellulose derivative with good biodegradability and low toxicity. It will not cause persistent pollution to the environment during use. This makes it an environmentally friendly choice in oil drilling, especially today when environmental protection requirements are becoming increasingly stringent, and HEC’s green properties add additional advantages to its application in drilling fluids.

Hydroxyethyl cellulose (HEC) plays a vital role in oil drilling. As a thickener, suspending agent, lubricant, and rheology regulator, HEC can significantly improve the performance of drilling fluids, increase drilling efficiency, and reduce the risks of well wall instability and wellbore blockage. In addition, HEC’s environmental friendliness makes it an indispensable material in the modern oil drilling process. With the advancement of technology, the application prospects of HEC in oil drilling will be broader and may show its potential in more fields.