Drilling fluid cost is an important part of the cost of the whole drilling project, which is usually expressed by the cost per unit footage, which involves the cost of some complex accidents (and can be avoided) encountered in the process of drilling and merging, such as sticking.
In many cases, the cost of drilling fluid also includes solid control, waste management and waste disposal. Therefore, it is equally important to reduce the cost drilling .Special maintenance and equipment are required to control the solid content of well fluid . If the waste liquid and cobalt cuttings produced by cobalt well fluid cannot be directly discharged into the surrounding environment, but must be transported away, generally speaking, it will also increase the cost of drilling fluid. Until now, the waste water-based drilling fluid can be directly discharged into the surrounding environment without any treatment. In many areas, government regulations prohibit the use of chromium containing substances, such as chromium lignosulfonate. In many areas, the use of chloride, nitrate and potassium salts in drilling fluid is forcibly limited, or the more common practice is the total conductivity of drilling fluid. Oil based drilling fluid, especially offshore, tends to be more limited than water-based drilling fluid, only oil-based drilling fluid with zero discharge measures (sometimes referred to as closed-loop system) can be used. In the United States, if the toxicity and biodegradability of synthetic based drilling fluid meet the standard requirements and do not produce fluorescence, it can usually be directly discharged into the sea. From this point of view, although the direct cost of synthetic based drilling fluid is generally higher than that of oil-based drilling fluid, its treatment cost is often lower. In this way, the use of synthetic based cobalt drilling fluid can be more economical than oil-based drilling fluid.

Choose the suitable drilling fluid and solids control equipment are the most important things to reduce the cost of drilling.