CO2 Pollution and Treatment Technology of Drilling Fluid in CCUS Burial Area of Jilin Oilfield

At present, CCUS has become a key technology that can efficiently reduce carbon emissions and promote low-carbon economic transformation. The CCUS technology for terrestrial low-permeability reservoirs in Jilin Oilfield has generally reached the international leading level. However, in the early drilling construction process, when the most commonly used water-based drilling fluid system is drilled into the formation containing CO2, it will make the rheological properties of drilling fluid deteriorate and the filtration loss is out of control, which seriously affects the performance of drilling fluid and drilling construction, and causes heavy losses to drilling operations. This paper introduces the main performances of drilling fluid after being polluted by CO2, such as PH decline, bubble generation, viscosity and shear rise. It is divided into three types of pollution. The pollution mechanism of each type is briefly analyzed, and different treatment strategies are proposed. Two wells have been successfully applied to effectively improve the performance of drilling fluid after CO2 pollution and meet the construction requirements. At present, this technology has gradually become the mainstream technology in Jilin oil field, It provides effective technical support and guarantee for Jilin oil field to drill in CCUS burial area.