Why drilling and completion fluids are more willing to choose potassium formate?
In traditional drilling and completion fluids, inorganic potassium salts are widely used. KCl is mostly used as K+ source in anti-collapse drilling fluids. However, with the increase of drilling depth and the difficulty of drilling, the anti-collapse (wellbore stability) of shale in deep formation has become a problem that drilling fluid technology must face and solve. Potassium formate is a new additive for drilling and completion fluids, which has the advantages of strong inhibition, high temperature stability, good compatibility, low corrosivity, good environmental protection and reservoir protection.
Potassium formate is mainly used to prepare injection fluid for water-bearing oil wells. Potassium formate has been used in drilling and completion fluids abroad since the late 1990s, especially in high density drilling and completion fluids, and has achieved very good results. The drilling fluid system prepared with potassium formate has the outstanding advantages of strong inhibition, good compatibility, reservoir protection, environmental protection, cost reduction and benefit increase.
1. The density of liquid potassium formate solution is about 1.57g/cm3, so the drilling fluid prepared has a wide density range, which is conducive to improving the penetration rate and reducing the total cost of production, and has a good protective effect on reservoirs.
2. Potassium formate has good compatibility with common polymer treatment agents, and can slow down the hydrolysis and oxidation degradation rate of various viscosity controllers and filtrate reducers under high temperature and pressure. Because some potassium formate drilling fluids can resist high temperature and have stable performance.
3. Potassium formate is a strong electrolyte. Therefore, potassium formate drilling fluid has a strong inhibitory effect on shale hydration expansion and dispersion, good compatibility with reservoir rocks and fluids, and the ability of salt resistance, calcium resistance and solid pollution resistance is also significantly better than fresh water drilling fluid.
4. The chemical characteristics of potassium formate itself are reducible, so the corrosiveness of metals is very weak. It will not cause corrosion damage to drilling tools, downhole equipment and materials, thus avoiding the corrosion problems caused by using halides such as NaCL, KCL, CaCL2 to prepare clean brine drilling fluids (even if corrosion inhibitors are added to brine drilling fluids, it will inevitably cause serious damage to drilling tools, etc.). Therefore, the use of potassium formate drilling fluid can effectively protect drilling tools and downhole equipment and reduce production costs.
Potassium formate is mainly used to prepare injection fluid for water-bearing oil wells. Potassium formate has been used in drilling and completion fluids abroad since the late 1990s, especially in high density drilling and completion fluids, and has achieved very good results. The drilling fluid system prepared with potassium formate has the outstanding advantages of strong inhibition, good compatibility, reservoir protection, environmental protection, cost reduction and benefit increase.
1. The density of liquid potassium formate solution is about 1.57g/cm3, so the drilling fluid prepared has a wide density range, which is conducive to improving the penetration rate and reducing the total cost of production, and has a good protective effect on reservoirs.
2. Potassium formate has good compatibility with common polymer treatment agents, and can slow down the hydrolysis and oxidation degradation rate of various viscosity controllers and filtrate reducers under high temperature and pressure. Because some potassium formate drilling fluids can resist high temperature and have stable performance.
3. Potassium formate is a strong electrolyte. Therefore, potassium formate drilling fluid has a strong inhibitory effect on shale hydration expansion and dispersion, good compatibility with reservoir rocks and fluids, and the ability of salt resistance, calcium resistance and solid pollution resistance is also significantly better than fresh water drilling fluid.
4. The chemical characteristics of potassium formate itself are reducible, so the corrosiveness of metals is very weak. It will not cause corrosion damage to drilling tools, downhole equipment and materials, thus avoiding the corrosion problems caused by using halides such as NaCL, KCL, CaCL2 to prepare clean brine drilling fluids (even if corrosion inhibitors are added to brine drilling fluids, it will inevitably cause serious damage to drilling tools, etc.). Therefore, the use of potassium formate drilling fluid can effectively protect drilling tools and downhole equipment and reduce production costs.
5. Potassium formate is non-toxic, and has the function of organic potassium fertilizer. Waste liquid can be recycled and biodegraded naturally. Therefore, using potassium formate as drilling fluid can not only meet the requirements of environmental protection, but also significantly reduce the cost of post-treatment.
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