In the process of oil drilling operations, drilling fluid costs are getting higher and higher, and environmentally-friendly drilling has stricter requirements for drilling fluids. In response to the "three highs" harsh downhole environment such as high temperature, high pressure and high salinity in ultra-deep wells, the popularization and use of potassium formate anti-collapse drilling fluid in petroleum drilling projects at home and abroad has become the main symbol of modern drilling fluid anti-collapse technology progress.

Drill cuttings generated at the bottom of the well during drilling operations are brought to the ground by the drilling fluid, and then the drilling fluid solid phase control equipment removes the drill cuttings and other harmful solid particles carried in the drilling fluid. Long-term drilling practices have shown that the presence of excessive useless solids destroys the performance of the drilling fluid, reduces the drilling rate and causes various downhole complications.

Therefore, the solid phase control of potassium formate drilling fluid is an important part of drilling fluid purification and an indispensable part of drilling technology. Potassium formate drilling fluid can accurately and effectively control the solid phase of the drilling fluid, which can reduce drilling torque and friction, reduce the pressure fluctuations of annulus suction, reduce the possibility of differential pressure sticking, increase the drilling speed, extend the life of the bit, and reduce Equipment wear, enhance the stability of the borehole wall, protect the oil and gas layer, and reduce the cost of drilling fluid, so as to provide the necessary conditions for scientific drilling.

A large number of indoor studies on potassium formate drilling fluid show that K⁺ has low hydration energy and has a suitable ion radius. It can significantly inhibit shale surface hydration and intercrystalline hydration, and has a unique and excellent anti-collapse effect of shale.

Traditional inorganic potassium salt anti-collapse drilling fluid systems mostly use KCl as the source of K⁺. However, as the drilling depth increases, the difficulty of drilling increases. The anti-collapse (wellbore stability) of deep formation mud and shale has become a necessity for drilling fluid technology. Problems faced and solved. The inhibition of traditional drilling fluids in the Bohai Sea can no longer meet the requirements of operations. In many blocks, complex conditions such as well wall collapse and stuck drilling occurred during drilling in the Shahejie formation. Many wells are forced to complete drilling if they fail to reach the completion depth. This not only greatly increased the cost of drilling, but more importantly, it failed to achieve the purpose of drilling deep formation geological data.

For this reason, a new anti-collapse theory must be applied to solve the anti-collapse requirements of the deep stratum in the Bohai Sea. The emergence of potassium formate activity theory effectively solves the above problems. Potassium formate enters the traditional PEM system of Bohai Sea, reduces the system activity to make it compatible with the formation, enhances the efficiency of the semi-permeable membrane, prevents a large amount of filtrate from entering the formation, thereby preventing the shale hydration and expansion of the deep formation, and finally achieves the purpose of preventing the collapse of the shale .

Offshore drilling is extremely challenging. Pore pressure, fracture gradient and complex geological structure formation may cause many problems. Potassium formate drilling fluid has the characteristics of good anti-collapse performance, protection of oil and gas reservoirs, low corrosiveness, environmental protection and recyclability. It is the development trend of environmentally friendly drilling fluids and reduces the occurrence of more catastrophic events.