Previously, drilling fluid was a multi-phase colloidal suspension containing chemical additives, sewage and sewage oil. After the completion of the well in the past, the waste is passed. In terms of ecological environmental protection, drilling fluids are mainly treated by open centralized recovery, curing, exposure, landfilling, etc., which pollute the soil, water and air. At present, in order to reduce atmospheric pollution and improve the environment for oil field drilling, the widely used is potassium formate oil drilling fluid, which not only has the advantages of strong suppression, good compatibility, etc., but also non-toxic and non-corrosive.

Potassium formate oil drilling fluid is a kind of inorganic brine drilling fluid system. Compared with conventional inorganic brine drilling fluid, it has adjustable density (1.00~2.30g/cm³), which has little damage to the formation, low solid content, thin and tough mud cake and acidification, good wellbore cleaning ability, strong inhibition and corrosion. Low performance, low environmental pollution, can increase the polymer's high temperature stability and other advantages.

Compared with conventional polymer drilling fluids, potassium formate drilling fluids are distinguished by the fact that they do not require bentonite slurrying, which fundamentally overcomes the colloidal properties of the bentonit e dispersion system and the stability of shale formations in the drilling fluid retention system. Contradictions manifested by dispersion in liquid.

Nowadays, potassium formate oil drilling fluid has been used in strong water-sensitive formations, easy stuck formations, deep well borehole formations, and wells with complex pressure systems. The density can reach 1.60g/cm³ or more.

Domestic Southwest Petroleum Institute and University of Petroleum have conducted research, and Daqing and Dagang oilfields have been applied in the field and received significant results. Data show that potassium formate can improve the ability of biopolymers, and better achieve the transmission of cuttings and wellbore cleaning. Based on this characteristic, combined with the characteristics of Jidong Oilfield (formate cannot be recycled for the time being), the characteristics of shallow well formation in Block G104-5 were used. Formulated experiment of non-bentonite phase. Limestone powder was used to adjust the density in the experiment, and the system was evaluated from the aspects of inhibition, rock-carrying property and protection of oil and gas layers. The evaluation showed that the system had good performance in all aspects.

Modern drilling is all about green and pollution-free. The main role of potassium formate in the drilling and completion fluid is potassium ion, which can be completely dissociated. At the same dosage, the effective K concentration is higher than potassium chloride, and there is no anion chloride. Pollution, the surface tension of the filtrate is significantly greater than that of potassium chloride drilling and completion fluid systems, and the flow resistance into the formation is large, which not only inhibits clay hydration and dispersion and expansion, prevents formation shrinkage, but also does not interfere with electrical measurements, and has low corrosion, while avoiding Oil layer pollution.