Development and Application of Environmental Friendly High Temperature Resistant Biomass Synthetic Resin Filtrate Reducer in Yuanba Area

In view of the fact that the marine carbonate formation in Yuanba area is often polluted by acid radical and hydrogen sulfide, which causes the viscosity and water loss of drilling fluid to rise, the temperature resistance to decline, and the flow pattern to be difficult to control, bringing great challenges to on-site maintenance. In this paper, a bio chemical method is proposed to modify lignin to develop an environment-friendly filtration reducer LDR of biomass synthetic resin with a cluster multi branch structure. The performance evaluation results show that the product has a temperature resistance of 200 ℃, a salt resistance of 25%, and a calcium resistance of 3,000 mg/L, showing a strong temperature and salt resistance performance. With this as the core of the high temperature resistant material, a high temperature resistant composite brine drilling fluid system is constructed by introducing potassium, calcium, and sodium plasma. Two wells were applied in Yuanba area. The field application shows that the maximum density of drilling fluid in Yuanba X-701 well is 2.34 g/cm³, the electric measurement shows that the temperature is 157 ℃, and the acid radical content is 21,157 mg/L. The system still has good rheological property and strong anti pollution ability. The two electric measurements successfully reached the bottom at one time, and the drilling fluid viscosity returned for 48 s after 7 consecutive days of standstill. It only took 28.88 days to complete the sidetracking task. The successful application of this system indicates that biomass resources have made a new breakthrough in high-temperature and high-density drilling fluid, effectively meeting the requirements of high-temperature slim hole for drilling fluid, and has good guidance and reference significance for deep wells and ultra deep wells in Yuanba area.