The deeper the oil well is drilled, the more important the drilling fluid becomes. Does the drilling fluid need to meet the requirements for protecting oil and gas reservoirs? The answer is yes. The solid-phase potassium formate drilling fluid is beneficial to protect oil and gas formations, and will not cause problems such as blockage of oil and gas formations by clay particles and water blocking effect, and will increase the productivity of production formations.

Reasons for oil and gas layer damage during drilling:

1. The dispersed phase particles in the drilling fluid block the oil and gas layer;

2. Damage caused by the incompatibility of drilling fluid filtrate with oil and gas reservoir rocks;

3. Damage caused by the incompatibility of drilling fluid filtrate and reservoir fluid;

4. Damage caused by changes in phase permeability;

5. Oil and gas formation damage caused by sharp changes in negative pressure difference.

The performance of drilling fluid is closely related to the quality of solid phase, filtrate and mud cake. The drilling and completion fluid prepared with potassium formate as the main raw material and salt water is the most commonly used drilling fluid system for oil and gas formation protection.

Potassium formate drilling fluid density adjustment: adjusted by adding hydrochloride. The maximum density of the base fluid can reach 2.3g/cm3. It can be adjusted according to the pressure of the oil and gas layer and the design requirements of drilling and completion fluids.

The characteristics of potassium formate drilling fluid can meet the basic requirements of protecting oil and gas formation drilling fluid:

1. It is easy to achieve low solid phase and low viscosity under high density;

2. Highly mineralized brine can prevent clay from hydration, swelling, dispersion and migration;

3. The brine contains no halide, no corrosion inhibitor, and the corrosion rate is extremely low;

4. Reservoir damage is small, and it is a drilling fluid system that is currently developing rapidly.

Therefore, after drilling the oil and gas layer, the drilling fluid contacts the oil and gas layer. In order to prevent the drilling fluid from damaging the oil and gas reservoirs, the use of potassium formate drilling fluid can achieve small water loss, thin mud cake (after the drilling fluid loses water, solid particles form a mud cake ring on the well wall), low solid content, and filtrate Low hydration (chemical interaction between filtrate and liquid in the formation after entering the formation) and other effects.